CN115746295B

CN115746295B - High-strength high-toughness high-barrier polyester amide and preparation method thereof

Info

Publication number: CN115746295B
Application number: CN202211503834.5A
Authority: CN
Inventors: 吴林波; 孟洪旭; 李伯耿
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2022-11-28
Filing date: 2022-11-28
Publication date: 2024-05-31
Anticipated expiration: 2042-11-28
Also published as: CN115746295A

Abstract

The invention relates to the technical field of high polymer materials, and discloses a high-strength high-toughness high-barrier polyester amide and a preparation method thereof, wherein when R ₂ is alkylene or substituted alkylene with main chain carbon number of 5 or 6, the polyester amide comprises 88-95mol% of a repeating unit shown in a formula (I) and 5-12mol% of a repeating unit shown in a formula (II); or, when R ₂ is an alkylene group or a substituted alkylene group having 7 to 12 carbon atoms in the main chain, 65 to 90mol% of the repeating unit represented by the formula (I) and 10 to 35mol% of the repeating unit represented by the formula (II) are included. The preparation method comprises mixing dibasic acid or diester thereof, dihydric alcohol and diamine to obtain a mixture, and pre-polymerizing and polycondensing to obtain the final product. The invention takes diamine with specific chain length and dosage as comonomer to participate in copolymerization with short chain dihydric alcohol, and can effectively maintain excellent mechanical strength and modulus, gas barrier property and glass transition temperature while obviously improving the tensile toughness of furan dicarboxylic acid polyester with brittleness such as PEF, PPF and the like. (I)(II)

Description

High-strength high-toughness high-barrier polyester amide and preparation method thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a high-strength high-toughness high-barrier polyester amide and a preparation method thereof.

Background

Furandicarboxylic acid (FDCA) is an important biobased diacid monomer with aromatic and physicochemical properties similar to those of terephthalic acid (TPA), and is considered to be an ideal TPA replacement or upgrade product for the synthesis of polymeric materials such as polyesters, polyamides, and plasticizers. Compared with terephthalic acid polyesters such as polyethylene terephthalate (PET), poly (1, 3-propylene terephthalate) (PPT, also called PTF), and the like, furan dicarboxylic acid polyesters such as poly (ethylene furandicarboxylate) (PEF), poly (1, 3-propylene furandicarboxylate) (PPF, also called PTF), and the like have higher glass transition temperature (T _g), mechanical strength, modulus, and gas barrier property, and provide a new opportunity for the selection of high-barrier packaging materials. However, PEF and PPF also suffer from significant performance deficiencies compared to PET and PPT, such as insufficient tensile and impact toughness, and elongation at break of typically only 2-5% affecting their processing and application, and need to be modified while retaining the original performance advantages.

Copolymerization is a common means of improving polymer properties. For PEF and PPF, the tensile toughness of the copolyester can be improved to a large extent by introducing flexible aliphatic dibasic acid or dihydric alcohol and other monomers to synthesize the copolyester, but the glass transition temperature, tensile strength and modulus and gas barrier property are often reduced significantly. For example, document 1 (Journal of Applied Polymer Science,2018,135, 46076) reports that dodecanedioic acid is used as a comonomer to synthesize a series of PEDoF copolyesters, and the elongation at break is 380% while maintaining a certain tensile modulus (1.2 GPa) and strength (45 MPa), but the T _g is significantly reduced. The Chinese patent CN 108264634A discloses a2, 5-furandicarboxylic acid copolyester and a preparation method thereof, cyclohexane dicarboxylic acid or isoidide dimethyl ester is used as a comonomer to carry out copolymerization modification on PEF and PPF, the copolyester with the comonomer content of 30-50mol percent has better modulus, strength and elongation at break, the elongation at break is improved to be more than 30%, the tensile modulus is 0.84-1.7GPa, the tensile strength is 36-54MPa, the tensile modulus and the strength are still obviously reduced compared with the PEF and the PPF, and the T _g is also obviously reduced to 48-53 ℃.

Since the high gas barrier properties of PEF benefit from the furan ring, copolymerization with aliphatic dibasic acids results in reduced FDCA content, which tends to result in reduced gas barrier properties; in contrast, copolymerization with glycol is advantageous in maintaining a high FDCA content, thereby being advantageous in maintaining gas barrier properties. Document 2 (Polymer, 2016,103, vol.26, 1-8) synthesizes a series of PECF copolyesters with 1, 4-Cyclohexanedimethanol (CHDM) as comonomer, which have a greatly improved toughness (50-186% elongation at break) at a cyclohexanedimethanol furandicarboxylate repeat unit content of 32-76mol% while retaining good gas barrier properties (O ₂ and CO ₂ barrier properties of 4 times higher than PET).

The Chinese patent CN 108129644A adopts CHDM to copolymerize and modify PEF, PPF and PBF, after 45mol% of CHDM of the total diol is introduced, the copolyester improves the breaking elongation (to 130-220%), has good gas barrier property and higher T _g, but compared with PEF, the tensile modulus and strength of the copolyester are obviously reduced (the reduction amplitude is 20-32% and 9-38% respectively).

The Chinese patent CN 108409949A discloses a2, 5-furandicarboxylic acid based copolyester material and a preparation method thereof, wherein 1, 4-Cyclohexanedimethanol (CHDM) is adopted to copolymerize and modify PPF to synthesize PTCF copolyester, when the molar percentage of the CHDM is more than 30mol percent, the toughness of the copolyester is greatly improved (the elongation at break is 100-170 percent), and simultaneously, the higher glass transition temperature (65-75 ℃) and the better gas barrier property (O ₂ barrier property is higher than PET) are maintained. These systems with CHDM as a glycol comonomer achieve better copolymerization toughening modification effects at higher CHDM levels (at least 30 mol%), but high CHDM levels undoubtedly increase the cost of the copolymer. Document 3 (Biomacromolecules, 2019,20, volume 353-364) reports that copolymerizing a modified PEF with a small amount of 1, 5-pentanediol can significantly improve the tensile toughness of the PEF and maintain a very high tensile modulus and yield strength, a high glass transition temperature and gas barrier properties, but still a large decrease in the breaking strength.

Lactones may also be used as comonomers. Document 4 (European Polymer Journal,2018,109, volumes 191-197) reports that copolymerization of PEF with epsilon-caprolactone gives a series of samples P (EF-co-CL) in which the elongation at break is significantly improved (up to 30-40%) at 20-30mol% addition; when the addition amount is 40mol%, the elongation at break of the copolymer is up to 980%, and meanwhile, the higher modulus (1.2 GPa) and strength (51 MPa) are maintained, but the T _g of the copolymer is obviously reduced to 34 ℃, and the gas barrier property is not reported. The Chinese patent CN 108467479A discloses a toughened 2, 5-furandicarboxylic acid copolyester and a preparation method thereof, a series of copolyesters synthesized by taking 2, 5-furandicarboxylic acid monomer, dihydric alcohol and lactone as raw materials have higher elongation at break and Young modulus, but the T _g is obviously reduced to 50 ℃, and the gas barrier property is not reported.

Chinese patent CN 102432847a discloses copolyesters of furandicarboxylic acid, C ₂-C₈ linear diol and terephthalic acid with glass transition temperatures similar to the corresponding polyethylene terephthalate, but without regard to barrier and mechanical properties. Document 4 (journal of Polymer, volume 2013,8, 1092-1098) reports a rigid diacid monomer-terephthalic acid co-modified PEF. Compared with PEF (polyethylene terephthalate) homo-polyester, the obtained copolyester has the advantages that the elongation at break is obviously improved only when the terephthalic acid content is up to 70-90mol%, the elongation at break is improved only when the terephthalic acid content is not 70-90mol%, and the strength and the modulus are lower. It can be seen that the use of terephthalic acid modified PEF can better maintain a high glass transition temperature, but does not achieve a significant toughening modification effect.

Chinese patent CN 102336906A discloses furan-based polyesteramides synthesized by copolycondensation of furandicarboxylic acid or its dimethyl ester, C ₂-C₄ linear diol and C ₂-C₄ linear diamine, which contain 10-20mol% furandicarboxyl diamine repeat units, have higher melting point, faster crystallization speed and better hydrolysis resistance than the corresponding furandicarboxylic acid polyesters, but mechanical properties and gas barrier properties are not reported.

However, it has been reported in the literature that polyamides synthesized from aliphatic diamines and furandicarboxylic acids and their diesters exhibit different performance characteristics than polyesters synthesized from aliphatic diols and furandicarboxylic acids and their diesters. For furan dicarboxylic polyesters, when the carbon chain of the diol is short (C ₂-C₅, especially C ₂、C₃ and C ₅), the corresponding polyesters are less crystalline; when the carbon chain of the glycol is long (C ₆-C₁₀), the corresponding polyester is very easy to crystallize; the toughness of the alloy is also improved along with the increase of the carbon chain of the dihydric alcohol. However, for furan dicarboxylic acid polyamide, when the carbon chain of diamine is shorter (C ₂-C₄), the corresponding polyamide is easier to crystallize, but has high melting point, difficult processing and unreported mechanical properties; when the carbon chain of the diamine is long (C ₆ or more), the corresponding polyamide is difficult to crystallize (document 5:European Polymer Journal 178,111496,2022) and has poor toughness, for example, P6F shows brittle fracture in tensile test and elongation at break is only 3.4% (document 6: polym. Chem.,13,3433,2022). Therefore, it is considered that aliphatic diamine is a polyester which is difficult to copolymerize and toughen as a comonomer of furan dicarboxylic acid polyester, and is more difficult to obtain a polyester having good toughness, mechanical strength and gas barrier property than a dibasic acid, a dibasic alcohol and a lactone comonomer.

In summary, for furan dicarboxylic acid polyesters PEF and PPF which are excellent in mechanical strength, modulus, gas barrier property, high in glass transition temperature and brittle in property, how to significantly improve the tensile toughness of the furan dicarboxylic acid polyesters PEF and PPF by introducing a small amount of comonomer through random copolymerization, and meanwhile, the advantageous properties of mechanical strength, modulus, gas barrier property, glass transition temperature and the like of the furan dicarboxylic acid polyesters are maintained efficiently, and the technical problems to be solved are still needed for PEF and PPF modification.

Disclosure of Invention

The invention aims to solve the technical problems that in the prior art, mechanical strength, tensile modulus, glass transition temperature and gas barrier property of furan dicarboxylic acid polyesters such as PEF, PPF and the like are obviously reduced and toughness and other excellent properties are not compatible, and provides a PEF and PPF copolymerization modified high-strength high-toughness high-barrier polyester amide.

In order to achieve the above purpose, the invention adopts the following technical scheme:

A high-strength high-toughness high-barrier polyester amide comprises 88-95mol% of furandicarboxylic acid glycol ester repeating units shown in a formula (I) and 5-12mol% of furandicarboxylic acid diamide repeating units shown in a formula (II); wherein R ₁ is alkylene or substituted alkylene with the main chain carbon number less than or equal to 3, and R ₂ is alkylene or substituted alkylene with the main chain carbon number of 5 or 6;

Or, comprises 65 to 90mol% of furandicarboxylic acid glycol ester repeating units represented by the formula (I) and 10 to 35mol% of furandicarboxylic acid diamine repeating units represented by the formula (II); wherein R ₁ is alkylene or substituted alkylene with the main chain carbon number less than or equal to 3, and R ₂ is alkylene or substituted alkylene with the main chain carbon number of 7-12:

according to the invention, the aliphatic diamine with a specific chain length (C5-C12) is used as a comonomer for the first time, and is copolymerized with the furandicarboxylic acid or the diester thereof and the aliphatic diol with the main chain carbon number not exceeding 3 is used for preparing the polyesteramide, so that the toughening of the brittle furandicarboxylic acid polyester such as PEF, PPF and the like is realized unexpectedly in a specific composition range, the effect of effectively keeping the excellent mechanical strength, modulus, gas barrier property and glass transition temperature of the furandicarboxylic acid polyester while obviously enhancing the tensile toughness is realized, and the problem that the toughness and other excellent properties cannot be obtained in the prior art is solved.

And the polyester amide with excellent comprehensive performance can be obtained by the aliphatic diamine with different chain lengths in different composition ranges. When the carbon atom of the diamine is 5 or 6, the composition of the furandicarboxylic acid diamide repeating unit can obtain excellent toughening effect in a narrow range such as 5 to 12mol%, and the toughness of the polyester amide is poor after the proportion is too low or too high, such as less than 5% or more than 12%; when the carbon atom of the diamine is 7 to 12, the composition of the furandicarboxylic acid diamide repeating unit can obtain an excellent toughening effect in a higher and wider range, for example, 10 to 35mol%, and if the composition exceeds the range, the toughening effect cannot be obtained.

Preferably, wherein R ₂ is an alkylene or substituted alkylene having 5 to 6, 10 to 12 carbon atoms in the main chain. The corresponding diamine has easily available raw materials.

Preferably, the furandicarboxylic acid glycol ester repeating unit is a 2, 5-furandicarboxylic acid glycol ester repeating unit; the furan dicarboxamide repeating unit is a 2, 5-furan dicarboxamide repeating unit. 2, 5-furandicarboxylic acid or its diester is more readily available and less costly than 3, 4-furandicarboxylic acid or its diester.

Preferably, R ₁ is selected from one of ethylene, 1, 3-propylene or 2-methyl-1, 3-propylene, and R ₂ is selected from one of pentamethylene, hexamethylene or decamethylene. In the alkylene or substituted alkylene with the carbon number of the main chain not exceeding 3, the preferable dihydric alcohol corresponding to R ₁ is primary alcohol, the reaction activity is higher, and the polymer with high molecular weight is prepared. The diamine raw material corresponding to the preferable R ₂ is easier to obtain, and is favorable for realizing the modification effect of toughness and other excellent performances.

Further, the polyesteramide comprises 88 to 94 mole percent of 2, 5-furandicarboxylic acid glycol ester repeat units and 6 to 12 mole percent of 2, 5-furandicarboxylic acid hexamethylenediamine repeat units; when R ₂ is hexamethylene, the proportion of the 2, 5-furan dicarboxylic acid hexamethylenediamine repeating unit is more suitable at 6-12mol percent, and the toughness, tensile strength, gas barrier property and other properties of the polyester amide are better.

Or, the polyesteramide comprises 70 to 90mol% of furandicarboxylic acid glycol ester repeating units and 10 to 30mol% of furandicarboxylic acid decamethylene diamine repeating units. When R ₂ is decamethylene, the proportion of the repeating units of 2, 5-furandicarboxylic acid decamethylene diamine is more preferably from 10 to 30 mol%.

Still further, the polyesteramide comprises 88 to 92 mole percent ethylene 2, 5-furandicarboxylate repeat units and 8 to 12 mole percent hexamethylene 2, 5-furandicarboxamide repeat units; the polyester amide toughness is better at this ratio. Further, the polyesteramide comprises 90 to 92 mole percent of ethylene glycol 2, 5-furandicarboxylate repeat units and 8 to 10 mole percent of hexamethylene 2, 5-furandicarboxamide repeat units

Or, the polyesteramide comprises 80 to 90mol% of ethylene furandicarboxylate repeat units and 10 to 20mol% of furan dicarboxyl decamethylene diamine repeat units. The added amount of the decanediamine is too large, the glass transition temperature of the polyesteramide is reduced more, the mechanical strength of the material is affected, and the comprehensive performance is better under the proportion.

The characteristic viscosity number of the polyesteramide is more than or equal to 0.8dL/g, the Young modulus is more than or equal to 2.0GPa, the tensile breaking strength is more than or equal to 60MPa, the breaking elongation is more than or equal to 10%, and the oxygen permeability coefficient is less than or equal to 0.02barrer. According to the invention, aliphatic diamine with proper chain length is used as a comonomer, and rigid/brittle polyesters such as PEF, PPF and the like are subjected to copolymerization modification to synthesize the polyesteramide, so that the stretching and toughening effects are obviously improved within a specific composition range, an obvious yield phenomenon appears in the stretching process, the yield strength reaches more than 90MPa, the elongation at break is improved to more than 10%, even more than 90%, and meanwhile, the excellent performances such as high T _g, excellent tensile strength and modulus, gas barrier property and the like are maintained. In some embodiments, the polyester amide has an intrinsic viscosity of 1.0dL/g or greater, and a high intrinsic viscosity is advantageous for improving the tensile toughness and also for maintaining or improving the tensile strength.

Preferably, the Young modulus of the polyesteramide is more than or equal to 3.0GPa, the tensile breaking strength is more than or equal to 60MPa, the breaking elongation is more than or equal to 20%, and the oxygen permeability coefficient is less than or equal to 0.015barrer.

Further preferably, the Young's modulus of the polyesteramide is more than or equal to 3.0GPa, the tensile breaking strength is more than or equal to 90MPa, the breaking elongation is more than or equal to 50%, and the oxygen permeability coefficient is less than or equal to 0.010barrer.

In general, the copolymerization of rigid/brittle polymers with monomers of ductile homopolymers as comonomers improves the toughness of the rigid/brittle polymers to some extent within a suitable composition range, but also tends to result in a significant decrease in tensile modulus, strength, glass transition temperature, and other physical properties such as gas barrier. If a hard and brittle homopolymer monomer is used as a comonomer, the physical and mechanical properties such as tensile modulus, strength, glass transition temperature and the like are favorably maintained, but the effect of improving or remarkably improving the toughness is often difficult to achieve.

On the other hand, for furan dicarboxylic acid polyamide, when the carbon chain of aliphatic diamine is shorter (C ₂-C₄), the corresponding polyamide is easier to crystallize, but has high melting point, difficult processing and unreported mechanical properties; when the carbon chain of the diamine is longer (above C ₆), the corresponding polyamide is on the contrary difficult to crystallize (document 5:European Polymer Journal 178,111496,2022), and the toughness is also poor, and document (document 6: polym. Chem.,13,3433,2022) reports that P6F shows brittle fracture in tensile test, and the elongation at break is only 3.4%.

However, the invention surprisingly discovers that by adopting aliphatic diamine with proper chain length as a comonomer, the rigid/brittle polyesters such as PEF, PPF and the like are copolymerized and modified to synthesize polyesteramide, and in a specific composition range, the tensile toughness can be obviously improved, the brittle fracture is changed into ductile fracture, the elongation at break is improved from 2-4% to 10% or even more than 90%, the unexpectedly high tensile modulus, the strength, the glass transition temperature, the gas barrier property and other physical and mechanical properties can be well maintained, and the modification effect of the dihydric alcohol with the same carbon chain length can be achieved.

The invention also provides a preparation method of the high-strength high-toughness high-barrier polyester amide, which comprises the following steps:

step 1, evenly mixing furandicarboxylic acid or diester thereof, dihydric alcohol with main chain carbon number less than or equal to 3, diamine with main chain carbon number of 5-12 and a catalyst to obtain a reaction mixture;

Step 2, heating the reaction mixture to 170-210 ℃ to carry out oligomerization reaction until the reaction degree of furandicarboxylic acid or diester thereof reaches more than 90%, thereby obtaining an intermediate product;

step 3, heating the reaction system to 230-260 ℃, reducing the pressure to below 200Pa, and performing polycondensation to obtain the polyesteramide;

The mol ratio of the dihydric alcohol to the furandicarboxylic acid or the diester thereof is 1.1:1-3:1;

When the main chain carbon number of the diamine is 5 or 6, the molar ratio of the diamine to the furandicarboxylic acid or diester thereof is 0.05-0.12:1;

when the main chain carbon number of the diamine is 7-12, the mole ratio of the diamine to the furandicarboxylic acid or diester thereof is 0.10-0.35:1.

Preferably, the dihydric alcohol is selected from any one of ethylene glycol, 1, 3-propylene glycol or 2-methyl-1, 3-propylene glycol; preferably primary alcohols, which facilitate the preparation of high molecular weight, high viscosity polyesteramides; the diamine is selected from any one of 1, 5-pentanediamine, 1, 6-hexanediamine or 1, 10-decanediamine. Suitable chain length and flexibility are beneficial to improving the toughness of the polyesteramide and ensuring that the glass transition temperature is not obviously reduced.

In the preparation method of the invention, the catalyst is a compound or a mixture based on at least one element of Ti, sn, sb, pb, ge, zn, fe, mn, co, zr, mg, V, al or rare earth elements.

The catalyst is at least one of zinc acetate, cobalt acetate, antimony acetate, manganese acetate, tetrabutyl titanate, isopropyl titanate, antimonous oxide, ethylene glycol antimony, ethylene glycol titanium and dibutyl tin oxide, and the dosage of the catalyst is 0.01-0.5wt% of the mass of the diacid or the diester thereof; the catalyst is added to increase the reaction rate, accelerate the reaction progress and increase the yield.

Adding a stabilizer in the step (2) or (3), wherein the stabilizer comprises at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, trimethyl phosphate, dimethyl phosphate, triphenyl phosphate, diphenyl phosphate, triphenyl phosphite, diphenyl phosphite, ammonium phosphite and ammonium dihydrogen phosphate; the mass of the stabilizer is 0.01-0.5wt% of the mass of the furandicarboxylic acid or diester thereof;

In the step (2), the temperature of the esterification reaction is 180-200 ℃; in the step (3), the temperature of the polycondensation reaction is 230-255 ℃, and the absolute pressure of the polycondensation reaction is 5-150Pa.

Compared with the prior art, the invention has the following beneficial effects:

(1) In the invention, moderate C ₅-C₁₂ and long-chain aliphatic diamine are used as modified monomers to be copolymerized with C ₂-C₃ short-chain dihydric alcohol and furan dicarboxylic acid or diester thereof, so that the toughening of rigid/brittle furan dicarboxylic acid polyesters such as PEF and PPF is realized unexpectedly, and meanwhile, the high glass transition temperature, excellent mechanical strength and modulus and excellent gas barrier property of PEF and PPF can be maintained effectively.

(2) The invention can realize excellent copolymerization modification effect by only introducing diamine of 6-35mol%, has low cost and good effect, and the characteristic viscosity number of the obtained copolyester is higher than 0.8dL/g, even higher than 1.0dL/g, thus realizing the preparation of high molecular weight polyesteramide, which is one of the reasons that the product can keep excellent mechanical properties.

(3) In the preparation method, all monomers are added in one pot, and esterification and amidation or transesterification and ester-amide exchange reactions are simultaneously carried out, so that compared with the method of firstly synthesizing polyester prepolymer and polyamide prepolymer and then copolycondensing or firstly synthesizing polyester prepolymer and then adding diamine to carry out depolymerization and finally copolycondensing, the preparation method has the advantages of more efficient, economical and environment-friendly process, convenience for simplifying operation, reducing cost and being beneficial to realizing continuous and large-scale production.

Drawings

FIG. 1 shows nuclear magnetic resonance hydrogen spectra of polyester amide PE6F with different compositions.

FIG. 2 shows nuclear magnetic resonance hydrogen spectra of polyester amide PE10F with different compositions.

FIG. 3 shows the DSC second temperature rise profile of a polyesteramide PE6F of different composition.

FIG. 4 shows the DSC second temperature rise curve of a polyesteramide PE10F having a different composition.

FIG. 5 is a tensile stress-strain curve of a polyester amide PE6F of different composition.

FIG. 6 is a tensile stress-strain curve of a polyester amide PE10F of different composition.

Detailed Description

The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. Modifications and equivalents will occur to those skilled in the art upon understanding the present teachings without departing from the spirit and scope of the present teachings.

The raw materials used in the following embodiments are all commercially available and used as they are without treatment. The names and abbreviations of the monomers used are shown in Table 1:

TABLE 1 monomer names and abbreviations

Monomer name	Monomer abbreviations	Abbreviation for monomer residue
			Furandicarboxylic acid	FDCA	F
Furanedicarboxylic acid dimethyl ester	DMFD	F
			Ethylene glycol	EG	E
1, 3-Propanediol	PDO	P
			2-Methyl-1, 3-propanediol	MPO	M
1, 6-Hexanediol	HDO	H
			1, 5-Pentanediamine	PeDA	5
1, 6-Hexamethylenediamine	HDA	6
			1, 10-Decanediamine	DDA	10
1, 12-Dodecanediamine	DoDA	12

* And (3) injection: the abbreviations for diamine residues are indicated by the numbers of diamine carbon chain lengths, according to the convention for polyamides.

In the invention, the polyester amide synthesized by furan dicarboxylic acid or diester thereof, dihydric alcohol and diamine is named as PXY _z F, wherein P represents a polymer, X represents abbreviation of dihydric alcohol residue, Y represents abbreviation of dihydric amine residue, is distinguished from abbreviation of dihydric alcohol residue, and is represented by numbers without letters, F represents residue of furan dicarboxylic acid or diester thereof, z represents mole percent of furan dicarboxylic acid diamine repeating unit accounting for total amount of product repeating unit, and 2-position effective number is taken.

It is well known that during the synthesis of polyethylene furandicarboxylates (PEFs) and copolyesters thereof, etherification side reactions of the ethylene glycol or terminal hydroxyethyl groups can occur, resulting in the formation of small amounts of diethylene furandicarboxylate repeat units. In the present invention, when synthesizing a PEF-based polyesteramide, a small amount of diethylene glycol furandicarboxylate (DF) repeating units are generated in addition to ethylene glycol furandicarboxylate (EF) repeating units and furan dicarboxamide repeating units. Since DF is very low, it is convenient to calculate as EF repeating units in the present invention without distinguishing between the two repeating units, EF and DF.

The test analysis method employed in the present invention is described below.

Characteristic viscosity number: the intrinsic viscosity of the sample was measured using a semi-automatic viscometer, hangzhou, at 25℃and the solvent for PEF and its copolyesteramide was phenol/tetrachloroethane (w/w=3/2).

Nuclear magnetic hydrogen spectrum (¹ H NMR): about 10mg of the sample was dissolved in 0.5mL of deuterated trifluoroacetic acid (TFA-d ₁) with internal standard TMS, and tested by AC-80 nuclear magnetic resonance (400 MHz) from Bruker, germany.

Thermal transition: the samples were measured using a TA-Q200 Differential Scanning Calorimeter (DSC) using standard temperature rise-drop-temperature rise procedures. Firstly, heating from 30 ℃ to 280 ℃ at a heating rate of 10 ℃/min, and keeping for 5min; then cooling to 30 ℃ at a cooling rate of 10 ℃/min, and preserving heat for 5min; finally, the temperature is increased to 280 ℃ at a heating rate of 10 ℃/min.

Tensile properties: 6 groups of dumbbell bars with the thickness of 2mm and the width of 4mm are prepared by adopting a Haake MiniJet II miniature injection molding machine. Tensile testing was performed at 25℃and a tensile rate of 10mm/min using a model Roell Z020 universal materials tester, zwick, germany, according to ASTM D638, and the average value was taken as the test result.

Gas permeability: the polyester and polyesteramide samples were hot pressed to form film samples having a film thickness of about 300 μm. The oxygen permeability coefficient of the sample was measured using a BSG-33E gas permeability tester from the company of electromechanical technology, inc. of Sitang, guangzhou, china under conditions of 1atm, 23℃and high purity oxygen (99.9%). Each sample was tested for oxygen permeability coefficient of 3 thermoformed film samples, and the average value thereof was taken as the test result.

Example 1 Synthesis of polyesteramide PE6 ₉ F

2, 5-Furanedicarboxylic acid (78.3 g, 0.502 mol), ethylene glycol (59.0 g, 0.951 mol), 1, 6-hexamethylenediamine (5.8 g, 0.0499 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

The reaction mixture is subjected to normal pressure esterification/amidation reaction under the protection of nitrogen at 180-200 ℃ for 5h, and then an intermediate product is obtained.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1.3h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.2h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl hexamethylenediamine). The content of 6F repeating units was calculated to be 9.4mol% based on ¹ HNMR spectra, so the polyesteramide was designated PE6 ₉ F.

Example 2 polyester amide PE6 ₁₁ F

2, 5-Furanedicarboxylic acid (76.7 g, 0.491 mol), ethylene glycol (58.8 g, 0.947 mol), and 1, 6-hexamethylenediamine (7.0 g, 0.0602 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification/amidation reaction at 180-200 ℃ for 4.5h to obtain an intermediate product;

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 0.5h, is heated to 240 ℃, is subjected to reaction for 0.5h at 240 ℃, is heated to 255 ℃, is subjected to reaction for 0.5h at 255 ℃, and is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl hexamethylenediamine). The content of the 6F repeating unit was calculated to be 11.4mol% based on ¹ H NMR spectrum, so that the polyester amide was designated PE6 ₁₁ F.

EXAMPLE 3 Synthesis of polyesteramide PE10 ₁₄ F

2, 5-Furanedicarboxylic acid (69.7 g, 0.447 mol), ethylene glycol (51.7 g, 0.833 mol), and 1, 10-decanediamine (11.2 g, 0.0650 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification/amidation reaction at 180-200 ℃ for 5h to obtain an intermediate product;

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted for 2h at 240 ℃, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The content of the 10F mer was calculated from ¹ H NMR spectrum and found to be 13.6mol%, so that the polyesteramide was designated PE10 ₁₄ F.

Example 4 Synthesis of polyesteramide PE10 ₁₈ F

2, 5-Furandicarboxylic acid (67.8 g, 0.434 mol), ethylene glycol (49.8 g, 0.802 mol), and 1, 10-decanediamine (13.4 g, 0.0778 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 0.5h, is heated to 240 ℃ and is reacted for 1h at 240 ℃, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The content of AF mer was calculated to be 17.5mol% based on ¹ HNMR spectra, so the polyesteramide was designated PE10 ₁₈ F.

EXAMPLE 5 Synthesis of polyesteramide PE10 ₂₄ F

2, 5-Furandicarboxylic acid (65.5 g, 0.420 mol), ethylene glycol (45.6 g, 0.735 mol) and 1, 10-decanediamine (17.7 g, 0.103 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 0.5h, is heated to 240 ℃ and is reacted for 1h at 240 ℃, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The content of the 10F mer was 23.7mol% based on ¹ HNMR spectroscopy, so the polyesteramide was designated PE10 ₂₄ F.

EXAMPLE 6 Synthesis of polyester amide PE10 ₂₉ F

2, 5-Furanedicarboxylic acid (62.7 g, 0.402 mol), ethylene glycol (42.2 g, 0.680 mol), and 1, 10-decanediamine (20.4 g, 0.118 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted for 2h at 240 ℃, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The content of the 10F mer was calculated from ¹ H NMR spectrum and found to be 29.0mol%, so that the polyesteramide was designated PE10 ₂₉ F. Since the solubility of the polyesteramide in a phenol/tetrachloroethane solvent is poor, the intrinsic viscosity is not measured, and ¹ H NMR spectrum is measured only in a very dilute solution.

EXAMPLE 7 Synthesis of polyesteramide PP6 ₁₀ F

Dimethyl 2, 5-furandicarboxylate (92.1 g, 0.500 mol), 1, 3-propanediol (68.4 g, 0.90 mol) and 1, 6-hexamethylenediamine (6.3 g, 0.0542 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

The reaction mixture is subjected to normal pressure transesterification/transesterification-amide exchange reaction under the protection of nitrogen at the temperature of 170-200 ℃ for 4.5h, and then an intermediate product is obtained.

After the transesterification/transesterification-amid exchange reaction is finished, 0.1% of triphenyl phosphite is added into the intermediate product, the temperature is raised to 230 ℃ and the pressure is reduced to 50Pa within 45min, the constant temperature is kept for 1h, the temperature is raised to 240 ℃, the reaction is carried out for 2h at 240 ℃, and then the reaction is stopped, so as to obtain poly (2, 5-propylene furandicarboxylate-co-2, 5-furandicarboxyl hexamethylenediamine). The content of 6F mer was calculated to be 10.2mol% based on ¹ H NMR spectrum, so the polyesteramide was designated PP6 ₁₀ F.

EXAMPLE 8 Synthesis of polyesteramide PM10 ₂₄ F

Dimethyl 2, 5-furandicarboxylate (66.3 g, 0.360 mol), 2-methyl-1, 3-propanediol (57.3 g, 0.63 mol) and 1, 10-decanediamine (15.3 g, 0.0888 mol) were added to a 250mL flask and mixed well; then adding 0.2 percent of antimony trioxide and 0.3 percent of triphenyl phosphate by the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture carries out normal-pressure transesterification/ester-amide exchange reaction at 170-200 ℃ for 5.5h to obtain an intermediate product;

After the transesterification/transesterification-amid exchange reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.5h, and then the reaction is stopped to obtain poly (2, 5-furandicarboxylic acid 2-methyl-1, 3-propanediol ester-co-2, 5-furandicarboxylic acid decanediamine). The content of the 10F mer was calculated to be 24.3mol% based on ¹ H NMR spectrum, so the polyesteramide was designated PM10 ₂₄ F.

Example 9 polyester amide PE5 ₁₁ F

2, 5-Furanedicarboxylic acid (78.6 g, 0.504 mol), ethylene glycol (59.6 g, 0.960 mol), and 1, 5-pentanediamine (6.9 g, 0.0675 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 0.5h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.5h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furan dicarboxyl pentanediamine). The content of 5F repeating units was calculated to be 12.3mol% based on ¹ HNMR spectra, so the polyesteramide was designated PE5 ₁₂ F.

EXAMPLE 10 Synthesis of polyesteramide PE12 ₁₆ F

2, 5-Furanedicarboxylic acid (69.7 g, 0.447 mol), ethylene glycol (51.7 g, 0.833 mol), and 1, 12-dodecanediamine (15.5 g, 0.0774 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.5h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl dodecandiamine). The content of the 12F mer was calculated to be 15.6mol% based on ¹ HNMR spectra, so the polyesteramide was designated PE12 ₁₆ F.

Comparative example 1 Synthesis of homo-polyester PEF (without diamine monomer)

2, 5-Furanedicarboxylic acid (70.1 g, 0.449 mol) and ethylene glycol (57.8 g, 0.931 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium with the mass of 0.3 percent of the mass of the 2, 5-furandicarboxylic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification reaction at 180-200 ℃ for 3.5h to obtain an intermediate product;

After the esterification reaction is finished, the intermediate product is heated to 240 ℃ within 40min, the pressure is reduced to 50Pa, and the reaction is carried out for 4.5h at constant temperature, thus obtaining poly (ethylene 2, 5-furandicarboxylate), which is named PEF.

Comparative example 2 Synthesis of homo-polyamide P6F (without diol monomer)

2, 5-Furanedicarboxylic acid (60.7 g, 0.389 mol) and 1, 6-hexamethylenediamine (88.2 g, 0.759 mol) were added to a 250mL flask and mixed well; adding ethylene glycol titanium with the mass of 0.3 percent of the mass of the 2, 5-furandicarboxylic acid, and uniformly mixing to obtain a reaction mixture.

The reaction mixture reacts for 16 hours under the protection of nitrogen at the temperature of 140-200 ℃ to obtain an intermediate product;

Then heating to 230 ℃ and reducing the pressure to 50Pa in 45min, reacting for 1h at constant temperature, heating to 240 ℃, reacting for 2h at 240 ℃, heating to 255 ℃, reacting for 2h at 255 ℃, and stopping the reaction to obtain poly (2, 5-furandicarboxylic acid hexanediamine) which is marked as P6F. It was insoluble in trifluoroacetic acid and phenol/tetrachloroethane (mass ratio w/w=3/2), so ¹ H NMR spectrum and intrinsic viscosity were not measured. Comparative example 3 Synthesis of Polyesteramide PE6 ₄ F

2, 5-Furanedicarboxylic acid (75.5 g, 0.484 mol), ethylene glycol (58.0 g, 0.934 mol), and 1, 6-hexamethylenediamine (2.8 g, 0.0241 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification/amidation reaction at 180-200 ℃ for 6.5h to obtain an intermediate product;

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.5h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxylic acid hexamethylenediamine). The polyester amide was designated PE6 ₄ F, since the content of 6F mer was calculated to be 4.4mol% based on ¹ HNMR spectra. Comparative example 4 Synthesis of Polyesteramide PE6 ₁₃ F

2, 5-Furanedicarboxylic acid (66.9 g, 0.429 mol), ethylene glycol (49.4 g, 0.796 mol), and 1, 6-hexamethylenediamine (7.2 g, 0.0620 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification/amidation reaction at 180-200 ℃ for 6 hours to obtain an intermediate product;

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, reduced in pressure to 50Pa, subjected to constant temperature reaction for 0.5h, then heated to 240 ℃, subjected to reaction for 1h at 240 ℃, then heated to 255 ℃, subjected to reaction for 0.5h at 255 ℃, and then stopped to obtain poly (2, 5-furandicarboxylic acid ethylene glycol ester-co-2, 5-furandicarboxylic acid hexamethylenediamine). The content of 6F mer was calculated from ¹ H NMR spectrum and found to be 12.6mol%, so the polyesteramide was designated PE6 ₁₃ F.

Comparative example 5 Synthesis of Polyesteramide PE6 ₂₁ F

2, 5-Furanedicarboxylic acid (63.2 g, 0.405 mol), ethylene glycol (44.7 g, 0.720 mol), and 1, 6-hexamethylenediamine (10.6 g, 0.0912 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification/amidation reaction at 180-200 ℃ for 5.5h to obtain an intermediate product;

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃, is subjected to reaction for 1h at 240 ℃, is heated to 255 ℃, is subjected to reaction for 0.5h at 255 ℃, and is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl hexamethylenediamine). The content of 6F mer was 21.1mol% based on ¹ H NMR spectrum, so the polyesteramide was designated PE6 ₂₁ F.

Comparative example 6 Synthesis of Polyesteramide PE10 ₅ F

2, 5-Furanedicarboxylic acid (72.7 g, 0.466 mol), ethylene glycol (57.5 g, 0.926 mol), and 1, 10-decanediamine (4.8 g, 0.0279 mol) were added to a 250mL flask and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 1h, is heated to 240 ℃ and is reacted at 240 ℃ for 1.5h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The content of the 10F chain unit is calculated to be 5.3mol percent according to ¹ HNMR spectrum result, so the polyester amide is marked as PE10 ₅ F; . Comparative example 7 Synthesis of Polyesteramide PE10 ₉ F

2, 5-Furanedicarboxylic acid (71.6 g, 0.459 mol), ethylene glycol (51.4 g, 0.828 mol), and 1, 10-decanediamine (7.3 g, 0.0424 mol) were added to a 250mL flask, and mixed well; then adding ethylene glycol titanium accounting for 0.3 percent of the total mass of the dibasic acid, and uniformly mixing to obtain a reaction mixture.

The reaction mixture is subjected to normal pressure esterification/amidation reaction under the protection of nitrogen at 180-200 ℃ for 4.5h, and then an intermediate product is obtained.

After the esterification/amidation reaction is finished, the intermediate product is heated to 230 ℃ in 45min, is depressurized to 50Pa, is subjected to constant temperature reaction for 0.5h, is heated to 240 ℃ and is reacted at 240 ℃ for 0.5h, and then the reaction is stopped to obtain poly (2, 5-ethylene furandicarboxylate-co-2, 5-furandicarboxyl decanediamine). The polyester amide was designated PE10 ₉ F, since it had a 10F mer content of 8.7mol% as calculated from ¹ HNMR spectra. Comparative example 8 Synthesis of copolyester PEH ₁₉ F

2, 5-Furanedicarboxylic acid (70.0 g, 0.448 mol), ethylene glycol (50.2 g, 0.809 mol), and 1, 6-hexanediol (10.9 g, 0.0922 mol) were added to a 250mL flask, and mixed well; tetrabutyl titanate accounting for 0.3 percent of the mass of the 2, 5-furandicarboxylic acid is then added and evenly mixed to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification reaction for 1h at the temperature of 190 ℃, and then the temperature is raised to 200 ℃ for reaction for 3h, so as to obtain an intermediate product;

After the esterification reaction is finished, the intermediate product is heated to 230 ℃ and reduced to 50Pa in 40min, the reaction is carried out for 1h at constant temperature, then the temperature is raised to 240 ℃, the reaction is carried out for 3h at 240 ℃, and then the reaction is stopped, thus obtaining the poly (2, 5-furandicarboxylic acid glycol-co-hexanediol ester). The content of HF mer was 19.3mol% based on ¹ H NMR spectrum, so the polyesteramide was designated PEH ₁₉ F.

Comparative example 9 Synthesis of copolyester PEH ₂₈ F

2, 5-Furanedicarboxylic acid (66.7 g, 0.427 mol), ethylene glycol (44.8 g, 0.722 mol), and 1, 6-hexanediol (16.2 g, 0.137 mol) were added to a 250mL flask, and mixed well; tetrabutyl titanate accounting for 0.3 percent of the mass of the 2, 5-furandicarboxylic acid is then added and evenly mixed to obtain a reaction mixture.

Under the protection of nitrogen, the reaction mixture is subjected to normal pressure esterification reaction for 2 hours at the temperature of 190 ℃, and then the temperature is raised to 200 ℃ for reaction for 2 hours, so as to obtain an intermediate product;

After the esterification reaction is finished, the intermediate product is heated to 230 ℃ and reduced to 50Pa in 40min, the reaction is carried out for 1h at constant temperature, then the temperature is raised to 240 ℃, the reaction is carried out for 2.5h at 240 ℃, and then the reaction is stopped, thus obtaining the poly (2, 5-furandicarboxylic acid glycol-co-hexanediol ester). The content of HF mer was 28.2mol% based on ¹ H NMR spectrum, so the polyesteramide was designated PEH ₂₈ F.

Nuclear magnetic hydrogen spectra and chemical shift assignments of the PEF polyesters, PE6F polyester amides and PE10F polyester amides prepared in the examples and comparative examples are shown in fig. 1 and 2.

Taking the spectrum of example 1 as an example, the peak at 7.26ppm corresponds to the chemical shift of H atom (f) on the furan ring of the 2, 5-furandicarboxylic acid residue; the peak at 4.65ppm corresponds to the chemical shift of the ethylene H atom (a) attached to the ester group in the ethylene 2, 5-furandicarboxylate (EF) mer (note: mer also known as repeat unit). The spectral peaks at 3.43, 1.62 and 1.35ppm correspond to the chemical shift of the CH ₂ atom (g, H, i) on the 2, 5-furandicarboxhexanediamine (6F) mer, respectively, and the spectral peak at 2.07ppm corresponds to the chemical shift of the active H atom (e) of the amide bond and the hydrogen bonding of the deuterating agent with water. The spectral peaks at 4.54ppm and 4.02ppm correspond to chemical shifts of methylene groups (b, c) attached to the ester and ether linkages in the diethylene glycol 2, 5-furandicarboxylate (DF) mer. The nuclear magnetic hydrogen spectrum result shows that the polyester amide PE6F and PE10F with expected structures are successfully synthesized.

Because of the lower volatility and higher reactivity of the diamine, little loss occurs, almost all into the polymer chain, and more ethylene glycol is lost, the copolymer composition expressed as phi _YF (y=6 or 10) is substantially equal to the mole percent of diamine relative to FDCA. As described above, in the present invention, EF and DF links are not distinguished, and they are collectively referred to as EF links. From the above description, the copolymer composition (phi _YF) is defined and calculated as follows, see formula (1), where I _a、I_b、I_c, and I _g are the peak areas at chemical shifts a, b, c, and g, respectively.

The monomer copolymer compositions and intrinsic viscosity of the polyesteramides synthesized in the examples and comparative examples are summarized in Table 2. The polyester amides obtained in the examples all have an intrinsic viscosity greater than 0.8dL/g and some samples have an intrinsic viscosity greater than 1.0dL/g.

TABLE 2 monomer and copolymer compositions and intrinsic viscosity of PEF, P6F and polyesteramide prepared in examples and comparative examples

^a : Mole percent diamine relative to FDCA; ^b: mole percent of glycol relative to FDCA; ^c: the mole percent of diamine relative to the sum of diamine and glycol represents the monomer composition; ^d: YF means the mole percent of 6F or 10F mer to the sum of 6F or 10F mer, EF mer (containing DF mer), representing the copolymer composition; ^e: the characteristic viscosity number is 25.0 ℃, and the solvent is a mixed solvent of phenol and tetrachloroethane (mass ratio w/w=3/2); a ^*,c^*,d^*: hexanediol replaces diamine.

The DSC curves of examples 1-2 and comparative examples 1-5 are shown in FIG. 3, the DSC curves of examples 3-6 and comparative examples 1, 6, 7 are shown in FIG. 4, the tensile stress-strain curves are shown in FIG. 5, and the tensile stress-strain curves are shown in FIG. 6.

The T _g, tensile properties and oxygen permeability coefficients of PEFs, P6F and polyesteramides prepared in the examples and comparative examples are summarized in Table 3.

TABLE 3T _g, tensile Properties and oxygen permeability coefficients of PEFs, P6F and polyesteramides prepared in examples and comparative examples

^a : The glass transition temperature is obtained by DSC secondary temperature rise curve;

^b-f : young's modulus, yield strength, breaking strength, elongation at yield, elongation at break, measured at 25℃at a tensile rate of 10 mm/min;

^g : oxygen permeability coefficient, the sample was hot pressed into a film having a thickness of about 0.3mm, measured at 23 ℃ under 1atm high purity oxygen conditions in barrer,1 barrer=7.50E ^-18m³.m.m^-2.s^-1.Pa^-1.

From the results of comparative examples 1 and 2, it is clear that both unmodified PEF and P6F homopolymers are brittle polymers of high modulus, having an elongation at break of less than 5% and a high glass transition temperature. PEF has high oxygen barrier properties.

From the results of examples 1-2, it is evident that the copolymer modification of PEF with 1, 6-hexamethylenediamine as a comonomer produced polyester amides PE6 ₉ F and PE6 ₁₁ F having a characteristic viscosity number greater than 0.8dL/g, unexpectedly, the tensile toughness is significantly improved, the elongation at break is increased to 17-73%, and at the same time, the tensile modulus, the yield strength, the breaking strength, the glass transition temperature and the oxygen barrier property are well maintained, wherein the yield strength is >100MPa.

As can be seen from comparing examples 1-2 with comparative examples 3-5, it is more unexpected that PE6F polyesteramide only achieves good tensile toughness within a narrow composition range; when the content of 6F chain links is less than or equal to 4mol percent or more than or equal to 13mol percent, the toughness fracture characteristic is lost, and the brittle fracture is changed again. In fact, as the 6F content increases from 9.4mol% to 11.4mol%, the tensile toughness thereof has exhibited a tendency to decrease. The P6F homopolymer (comparative example 2) is also a brittle polymer.

The inventors also tried to replace 1, 6-hexamethylenediamine with 1, 5-pentanediamine in the proportion of example 2 in example 9, and found that copolymerization modification of PEF with 1, 5-pentanediamine as a comonomer can exert a toughening effect similar to that of 1, 6-hexamethylenediamine.

In examples 7 and 8, other dihydric alcohols were used, and the resulting polyesteramide had similar properties to those of the same proportions of ethylene glycol and diamine, and also had a toughening effect.

Comparing examples 3-6 with comparative examples 1 and comparative examples 6-7, it is clear that PE10F still exhibits brittle fracture behavior without tensile yield at a 10F mer content of 5-9 mole% for PE10F polyesteramides; however, when the content of the 10F chain links is 14-29mol%, PE10F shows ductile fracture behavior, tensile yield phenomenon occurs, the elongation at break reaches 42-90%, and the elongation at break tends to rise and then decline with the increase of the 10F content, namely the tensile toughness tends to be enhanced and then weakened. Therefore, it is reasonable to infer that PE10F also has tensile toughness over only a narrow composition range, but that PE10F has a broader composition range in which tensile toughness occurs than PE 6F.

The inventors also tried to replace 1, 10-decanediamine with 1, 12-dodecanediamine in the proportion of example 3 in example 10, and found that copolymerization modification of PEF with 1, 12-dodecanediamine as a comonomer can exert a toughening effect similar to that of 1, 10-decanediamine.

In summary, although the polyfurandicarboxylic acid amide (PYF) is a hard and brittle nylon material, a proper amount of medium-long chain diamine is used as a comonomer to have unexpected special stretching toughening modification effects on brittle furandicarboxylic acid polyesters such as PEF and PPF, and the obtained polyester amide has the characteristics of high characteristic viscosity, high glass transition temperature, high modulus, high strength, high stretching toughness and high barrier property in a specific composition range and can be used as high-performance materials such as engineering plastics and high barrier packages.

As is clear from the comparison of example 1 and comparative examples 8 to 9, when hexanediol is used as a comonomer for the copolymerization modification of PEF, the introduction of 19mol% of HF mer does not allow for a brittle-to-tough transition (comparative example 8), and when the HF mer content is as high as 28mol%, a brittle-to-tough transition is achieved, and the elongation at break reaches 54%, but the Young's modulus is reduced from 3.2GPa to 2.8GPa of PEF, the tensile breaking strength is significantly reduced from 87MPa to 33MPa of PEF, and the glass transition temperature is significantly reduced from 89 ℃ to 62 ℃ of PEF. In contrast, when hexamethylenediamine containing 6 carbon atoms is used as a comonomer, the brittle-ductile transition can be realized by introducing a small amount (9 mol%) of 6F chain link, the elongation at break is as high as 73%, the tensile toughness is obviously improved, and meanwhile, compared with PEF, the high Young's modulus (3.1 GPa vs.3.2 GPa), the tensile breaking strength (80 MPa vs.87 MPa), the glass transition temperature (88 ℃ vs.89 ℃) and the low oxygen permeability coefficient (0.0041 vs.0.0040 barrer) are well maintained. Compared with a dihydric alcohol comonomer, diamine with the same carbon atom is adopted as the comonomer, so that the PEF is more easily toughened, and the tensile modulus, the strength, the glass transition temperature and the gas barrier property of the PEF can be better maintained. And the dihydric alcohol as a comonomer cannot achieve the effects of toughening, mechanical strength and other performances.

Claims

1. A high-strength high-toughness high-barrier polyester amide is characterized by comprising 88-94mol% of a 2, 5-furandicarboxylic acid glycol ester repeating unit shown in a formula (I) and 6-12mol% of a 2, 5-furandicarboxylic acid diamine repeating unit shown in a formula (II); wherein R ₁ is alkylene or substituted alkylene with the main chain carbon number less than or equal to 3, and R ₂ is hexamethylene;

Or, comprises 70-90mol% of 2, 5-furandicarboxylic acid glycol ester repeating units shown in the formula (I) and 10-30mol% of 2, 5-furandicarboxylic acid diamine repeating units shown in the formula (II); wherein R ₁ is alkylene or substituted alkylene with the main chain carbon number less than or equal to 3, and R ₂ is alkylene or substituted alkylene with the main chain carbon number of 10-12:

(I wan)

(II)

The characteristic viscosity number of the polyesteramide is more than or equal to 0.8dL/g, the Young modulus is more than or equal to 2.0GPa, the tensile breaking strength is more than or equal to 60MPa, the breaking elongation is more than or equal to 10%, and the oxygen permeability coefficient is less than or equal to 0.02barrer.

2. The high-strength, high-toughness and high-barrier polyester amide according to claim 1,

R ₁ is selected from one of ethylene, 1, 3-propylene or 2-methyl-1, 3-propylene, and R ₂ is selected from one of hexamethylene or decamethylene.

3. The high strength, high toughness, high barrier polyester amide of claim 1, wherein the polyester amide comprises 70 to 90 mole percent furandicarboxylic acid glycol ester repeat units and 10 to 30 mole percent furandicarboxyl decanediamine repeat units.

4. The high strength, high toughness, high barrier polyester amide of claim 1, wherein the polyester amide comprises 88 to 92 mole percent ethylene 2, 5-furandicarboxylate repeat units and 8 to 12 mole percent 2, 5-furandicarboxyl hexamethylenediamine repeat units;

Or, the polyesteramide comprises 80 to 90mol% of ethylene furandicarboxylate repeat units and 10 to 20mol% of furan dicarboxyl decamethylene diamine repeat units.

5. The high-strength, high-toughness and high-barrier polyester amide according to claim 1, wherein the Young's modulus of the polyester amide is not less than 3.0GPa, the tensile breaking strength is not less than 60MPa, the elongation at break is not less than 20%, and the oxygen permeability coefficient is not more than 0.015barrer.

6. The method for producing a high-strength, high-toughness and high-barrier polyester amide according to any one of claims 1 to 5, comprising the steps of:

Step 1, uniformly mixing 2, 5-furandicarboxylic acid or diester thereof, dihydric alcohol with main chain carbon number less than or equal to 3, diamine with main chain carbon number of 6 and 10-12 and a catalyst to obtain a reaction mixture;

step 2, heating the reaction mixture to 170-210 ℃ to carry out oligomerization reaction until the reaction degree of the 2, 5-furandicarboxylic acid or diester thereof reaches more than 90%, thereby obtaining an intermediate product;

The mol ratio of the dihydric alcohol to the 2, 5-furandicarboxylic acid or the diester thereof is 1.1:1-3:1;

When the main chain carbon number of the diamine is 6, the diamine is 1, 6-hexamethylenediamine, and the molar ratio of the diamine to the 2, 5-furandicarboxylic acid or diester thereof is 0.06-0.12:1;

When the main chain carbon number of the diamine is 10-12, the molar ratio of the diamine to the 2, 5-furandicarboxylic acid or diester thereof is 0.10-0.30:1.

7. The method for producing a high-strength, high-toughness and high-barrier polyester amide according to claim 6, wherein the glycol is any one selected from ethylene glycol, 1, 3-propanediol and 2-methyl-1, 3-propanediol;

the diamine is selected from any one of 1, 6-hexamethylenediamine or 1, 10-decanediamine.

8. The method for preparing the high-strength high-toughness high-barrier polyester amide according to claim 6, wherein the catalyst is at least one selected from zinc acetate, cobalt acetate, antimony acetate, manganese acetate, tetrabutyl titanate, isopropyl titanate, antimony trioxide, ethylene glycol antimony, ethylene glycol titanium and dibutyl tin oxide, and the amount of the catalyst is 0.01-0.5wt% of the mass of the diacid or the diester thereof;

and/or adding a stabilizer in the step (2) or (3), wherein the stabilizer comprises at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, trimethyl phosphate, dimethyl phosphate, triphenyl phosphate, diphenyl phosphate, ammonium phosphite and monoammonium phosphate;

The mass of the stabilizer is 0.01-0.5wt% of the mass of the 2, 5-furandicarboxylic acid or diester thereof;

and/or, in the step (2), the temperature of the esterification reaction is 180-200 ℃; in the step (3), the temperature of the polycondensation reaction is 230-255 ℃, and the absolute pressure of the polycondensation reaction is 5-150Pa.