TWI695861B - Development of Nano-Carbon Fiber Dicyclopentadiene Composite Materials - Google Patents

Abstract

A modified norbornene nanocarbon fiber and preparation method thereof are obtained by acidifying and carbonizing the nanocarbon fiber and then esterifying the norbornene compound. The present invention further provides a modified carbon nanofiber-containing polydicyclopentadiene containing norbornene and a preparation method thereof. The modified carbon nanofiber and norcyclopentadiene modified by norbornene are subjected to ring-opening polymerization under catalyst catalysis In response. In this way, the mechanical and thermal stability of the polydicyclopentadiene material are improved.

Description

Development of Nano-Carbon Fiber Dicyclopentadiene Composite Materials

The invention relates to a nano carbon fiber-containing polydicyclopentadiene and a preparation method thereof, in particular to a nano carbon fiber-containing polydicyclopentadiene introduced with norbornene and a preparation method thereof.

Nano carbon fiber is a fiber material with both chemical inertness and semiconductor properties. It has light weight, high strength, high modulus of elasticity, high temperature resistance, acid resistance, strong electrical conductivity, long-term stress without creeping and fatigue resistance, and dimensional stability. Strong performance, high thermal conductivity, small friction coefficient, lubricity and other excellent properties. The main purpose of nano carbon fiber is to compound with resin, metal, ceramic and other substrates to make structural materials. Nano carbon fiber reinforced resin composite materials have the highest comprehensive index of specific strength and specific modulus among the existing structural materials; in areas with strict requirements such as density, stiffness, weight and fatigue characteristics, high temperature and chemical stability are also required With high properties, nano carbon fiber composite materials are quite advantageous.

Petroleum cracking is the mother of the chemical industry. At the same time, the extraction of commonly used chemicals is accompanied by the generation of many by-products. Among the C5 by-products, dicyclopentadiene (DCPD) is easy to separate and has good reactivity. In recent years Has been gradually valued. Dicyclopentadiene (DCPD) is a five-ring The aliphatic low-polar structure shows good chemical resistance, low humidity, UV resistance and excellent electrical properties. In addition, its rigid cyclic aliphatic structure can also be used to prepare light-weight composite materials with high mechanical properties. However, the homopolymer of dicyclopentadiene (DCPD) still has room for improvement in properties.

Due to the high surface energy of the carbon fiber surface, it will easily cause aggregation and make it difficult to disperse in the polymer. Therefore, the industry currently needs a simple method to introduce the norbornene structure into the nano carbon fiber, and make It can be evenly dispersed in dicyclopentadiene and then cured by a catalyst to obtain a composite material with high mechanical strength.

The main object of the present invention is to provide a modified carbon nanofiber of norbornene and a preparation method thereof, and introduce a norbornene (norbornene) structure into the carbon nanofiber. Another main object of the present invention is to further provide a modified carbon nanofiber polydicyclopentadiene containing norbornene and its preparation method, which is catalyzed by Grubbs' catalyst and obtained by means of ring-opening metathesis polymerization (ROMP) The cured product to prepare a uniform black polymer with excellent mechanical properties.

其中，R為O或NH之結構，n=7-10。 In order to achieve the above objective, according to the solution proposed by the present invention, a modified nano carbon fiber as shown in formula (I) is provided:

Among them, R is the structure of O or NH, n=7-10.

其中，n=7-10。 The present invention further provides a method for preparing modified carbon nanofibers according to formula (I). The steps include: (1) providing a carbon nanofiber and acidifying the carbon nanofibers; (2) carbonizing the carbonized nanofibers Carry out the chlorination reaction; (3) perform the esterification reaction of the nanocarbon fiber after the chlorination reaction with 5-norbornene-2-methanol or 5-norbornene-2-amine to obtain the formula (I)-1 or Modified nano carbon fiber of formula (I)-2:

Among them, n=7-10.

In the above, the acidification liquid system of step (1) is nitric acid or sulfuric acid, and the acidification reaction temperature is between 60°C and 100°C.

In the above, the chlorination liquid system of step (2) is thionyl chloride (SOCl ₂ ), and the chlorination reaction temperature is between 50°C and 80°C.

In the above, the reaction temperature of step (3) is between 50°C and 80°C.

其中，R為O或NH之結構。 The present invention further provides a modified nano-carbon fiber composition according to formula (II):

Among them, R is a structure of O or NH.

The present invention further provides a method for preparing a modified nano-carbon fiber composition as shown in formula (II). The modified nano-carbon fiber of formula (I) and dicyclopentadiene are subjected to ring opening under catalyst catalysis The polymerization reaction yields a modified nanocarbon fiber composition as shown in formula (II).

In the above, the reaction weight ratio of dicyclopentadiene to the modified nanocarbon fiber of formula (I) is between 100:0.1 and 100:3.

、

及

所組成之群組之一。 In the above, the catalyst is selected from

,

and

One of the groups formed.

In the above, the temperature of the ring-opening polymerization reaction is between 120°C and 180°C.

A modified norbornene-containing nanocarbon fiber polydicyclopentadiene of the present invention and its preparation method, firstly introducing norbornene (norbornene) structure into nanocarbon fiber, can increase the dispersibility of nanocarbon fiber in dicyclopentadiene , And then cured by Grubbs' catalyst, can further improve the mechanical properties.

The above summary, the following detailed description and the accompanying drawings are intended to further illustrate the methods, means and effects of the present invention to achieve the intended purpose. The other objects and advantages of the present invention will be explained in the subsequent description and drawings.

S101-S103‧‧‧Step

S201‧‧‧Step

The first figure is a flow chart of the preparation method of the modified nano carbon fiber and its modified nano carbon fiber composition of the present invention; the second figure is a schematic diagram of the synthesis of norbornene modified nano carbon fiber according to an embodiment of the present invention; Figure 3 is a schematic diagram of the synthesis of norbornene-modified nano carbon fiber polydicyclopentadiene composition according to an embodiment of the present invention; Figure 4 is an XRD spectrum analysis diagram of norbornene-modified nano carbon fiber according to an embodiment of the present invention; The fifth figure is the Raman spectrum analysis chart of the norbornene modified nano carbon fiber of the embodiment of the present invention; the sixth figure is the modified norbornene nano carbon of the embodiment of the present invention The TGA thermogravimetric analysis chart of the fiber; the seventh chart is a photo of the dispersion test of norbornene-modified nano carbon fiber in dicyclopentadiene according to an embodiment of the present invention.

The following is a description of the embodiments of the present invention by specific specific examples. Those skilled in the art can easily understand the advantages and effects of the present invention from the contents disclosed in this specification.

Please refer to the first figure, which is a flow chart of a method for preparing modified nano-carbon fiber and modified nano-carbon fiber composition of the present invention. As shown in the figure, a method for preparing modified carbon nanofibers of the present invention includes the steps of: (1) providing a carbon nanofiber and acidifying the carbon nanofiber S101; (2) acidifying the carbon nanofibers Carry out the chlorination reaction S102; (3) perform the esterification reaction of the nanocarbon fiber after the chlorination reaction with 5-norbornene-2-methanol or 5-norbornene-2-amine to obtain the formula (I)-1 Or modified nano carbon fiber S103 of formula (I)-2. The present invention further provides a method for preparing a modified nanocarbon fiber composition, which uses the modified nanocarbon fiber of formula (I)-1 or formula (I)-2 and dicyclopentadiene under catalyst catalysis, The ring-opening polymerization reaction is carried out to obtain the modified nanocarbon fiber composition S201 of formula (II).

其中，R為O或NH之結構，n=7-10。

Among them, R is the structure of O or NH, n=7-10.

Example:

Embodiment 1: Please refer to the second figure, which is a schematic diagram of synthesis of norbornene modified nano carbon fiber according to an embodiment of the present invention. As shown in the figure, in this embodiment, 3 grams of nano carbon fiber (long woven into short woven carbon fiber. Diameter: 6-8um, length: 100~130um, carbon content: 97% or more, Flexural strenth: 1725MPa Above, Flexural modulus: 124MPa or more) Place in a 100mL three-necked bottle, add 15ml of nitric acid, then slowly add 45ml of concentrated sulfuric acid (98%) and stir in an ice bath environment for 1 hour. Shake the machine for 1 hour, then increase the temperature at 60°C for two hours, 80°C for one hour, and 95°C for seven hours. After the reaction is complete, slowly drop the above solution into deionized water, let it settle overnight after waiting for precipitation, filter and take the filter cake and wash it several times to reach neutrality, and then put it in a 75°C oven for one day to obtain the formula (A) Acidified nano carbon fiber. The characteristic peak position of the acidified carbon fiber of formula (A) analyzed by Fourier transform infrared spectroscopy (FTIR) is as follows, 3500.8-3085cm ^-1 (OH stretch), 1580cm ^-1 (C=C stretch), 1729cm ^-1 (C=O stretch ). Next, take (A) 3g in a 100mL three-necked flask, add an excess of SOCl ₂ 20mL, add 0.1mL of dimethylformamide (DMF) as an initiator, pass nitrogen gas, and connect the reaction outlet with a concentration of A buffer bottle of 1M sodium hydroxide aqueous solution to neutralize the excess acid gas, the temperature is controlled at 65 ℃, and the reaction is carried out under a nitrogen environment for 24 hours. After the reaction is completed, the SOCl _{2 is} dried with a reduced-pressure concentrator to obtain the carbon nanofibers of formula (B).

Example 2: As shown in the flow of the second figure, 3 grams of acetyl carbon fiber of formula (B) was placed in a 100 mL three-necked reactor, 6 grams of Triethylamine and 50 mL of dehydrated tetrahydrofuran (THF) were added under an ice bath, and then Slowly add 6 grams of 5-norbornene-2-methanol, then gradually increase the temperature to 65°C and react for 24 hours under a nitrogen atmosphere. After the reaction is over, wash with a large amount of methanol, repeat multiple times to completely remove excess 5-norbornene-2-methanol and THF, and then put it in an oven at 75 ℃ for one day to obtain the modified nano carbon fiber of formula (I)-1 . Fourier transform infrared spectroscopy (FTIR) analysis showed characteristic peaks 3715-3085cm ^-1 OH are reduced, and there is generated a double bond at 1726cm ^-1 on the carbon-oxygen ester group (C = O), and at 2932cm ^-1 and 2854cm ^-1 is produced by -CH ₂ stretch of norbornene.

Example 3: As shown in the flow of the second figure, 3 grams of acetyl carbon fiber of formula (B) was placed in a 100 mL three-necked reactor, 6 grams of Triethylamine and 50 mL of dehydrated THF were added under an ice bath, and then slowly dropped 6 grams of 5-norbornene-2-amine, then gradually increase the temperature to 65°C, and react for 24 hours under a nitrogen atmosphere. After the reaction is completed, wash with methanol in large quantities and repeat several times to completely remove excess 5-norbornene-2-amine and THF was placed in an oven at 75°C for another day to obtain the modified nano carbon fiber of formula (I)-2. By Fourier transform infrared spectrometer (FTIR) analysis, it was found that the OH characteristic peak of 3715-3085cm ^-1 was reduced, and there were carbon and oxygen (C=O) double bonds on the amide group and -NH at 1711cm ^-1 and 1550cm ^-1 , respectively. Generation, and -CH ₂ stretch of norbornene was generated at 2932cm ^-1 and 2854cm ^-1 .

The present invention is to identify the modified IR nanocarbon fibers (I) -1, OH features can be found in a decrease in peak of 3715-3085cm ^-1, 1726cm ^-1 and the ester group has a carbon-oxygen (C = O) double bond Generated, and the -CH2 stretch of norbornene was produced at 2932 and 2854cm ^-1 ; similarly, the modified nano carbon fiber (I)-2 was identified by IR, which can be found at 1711 and 1550cm ^-1 , respectively. (C=O) The formation of double bond and -NH, and there is -CH ₂ stretch signal of norbornene at 2932 and 2854cm ^-1 . Please also refer to the fourth figure, which is an XRD spectrum analysis diagram of norbornene modified nano carbon fiber according to an embodiment of the present invention, and the modified nano carbon fiber is identified by a high resolutioh X-ray diffractometer (HRXRD) (I)-1, (I)-2, as shown in the figure, the carbon fiber layers are stacked closely between the layers, making the relative strength higher, but in the acidified carbon fiber (A) and modified nano carbon fiber (I)-1, ( In I)-2, because there are organic modified functional groups between the layers, it is not easy to form a regular and compact structure in the crystal stack, so that the relative strength exhibits a signal reduction and flattening phenomenon during acidification and modification, respectively. Amorphous crystal form.

Please refer to the fifth figure, which is a Raman spectrum analysis diagram of norbornene modified nano carbon fiber according to an embodiment of the present invention. 3D Nanometer Scale Raman PL Microspectrometer (3D Raman) Identification of modified nano carbon fiber (I)-1 and modified nano carbon fiber (I)-2. As shown in the figure, the ID/IG values (3.09/3.74) of (I)-1 and (I)-2 after being modified by two norbornene have obviously increased, confirming successful grafting to carbon fiber.

Please refer to the sixth diagram, which is a TGA thermogravimetric analysis diagram of norbornene-modified nanocarbon fiber according to an embodiment of the present invention. Using a TGA thermal analysis instrument with a flow rate of nitrogen and air of 20 mL/min, identify carbon nanofibers (CNF), acidified carbon nanofibers (A), and modified carbon nanofibers (I)-1, (I)-2. As shown in the figure, the T _d5% of carbon nanofibers (CNF) is 520℃, and the modified carbon nanofibers (I)-1 and (I)-2 show that their first degradation temperatures are 205℃ and 250℃, respectively. After 520 ℃, it is the cracking of carbon fiber, to calculate the grafting rate of various surface modified carbon fibers (the thermal degradation difference before and after 520 ℃ modified carbon fiber to calculate the surface grafting rate), after calculation, from Table 1 can It was found that the grafting rates of (I)-1 and (I)-2 were 52.7% and 39.8%, respectively. Through the above XRD, IR, TGA, Raman structure identification, it is known that carbon fibers (I)-1 and (I)-2 with norbornene structure have been successfully synthesized.

Please refer to the seventh figure, which is a photo of the dispersion test of norbornene-modified nanocarbon fiber in dicyclopentadiene (DCPD) according to an embodiment of the present invention. The present invention separately tests the dispersibility results of the mixed solution of nanometer carbon fiber (CNF)/DCPD, modified nanometer carbon fiber (I)-1/DCPD, and modified nanometer carbon fiber (I)-2/DCPD. As shown in the figure, the nano carbon fiber (CNF)/DCPD mixed liquid has obvious precipitation phenomenon in 10 minutes, otherwise, the modified nano carbon fiber (I)-1/DCPD, modified nano carbon fiber (I)-2/ DCPD can still maintain good dispersion in 10 minutes, so that it has enough time for processing. Looking further, at 60 minutes, the nanocarbon fiber (CNF)/DCPD mixed solution almost completely precipitated, but the modified nanocarbon fiber (I)-1/DCPD mixed solution and the modified nanocarbon fiber (I)-2 The /DCPD mixed solution still retains some microdispersity, and it can be confirmed again that the modified carbon nanofibers (I)-1 and (I)-2 of norbornene can indeed maintain a relatively good dispersion effect in DCPD.

Embodiment 4: Please refer to the third figure, which is a schematic diagram of the synthesis of norbornene modified nano carbon fiber polydicyclopentadiene composition according to an embodiment of the present invention. First, dicyclopentadiene (DCPD) and four different levels of modified nano-carbon fiber (I)-1 (0.1, 0.5, 1, 3wt%), using a membrane breaking machine (I)-1/DCPD Vibrate vigorously for 2 minutes to break the large-scale aggregation phenomenon, and then place it in an ultrasonic oscillating machine for 3~4 hours. After dispersion, first place Grubbs' second-generation catalyst and dichloromethane (DCM) at room temperature. 1:100 (mg/mg) ratio is mixed first, and then the prepared catalyst solution and (I)-1/DCPD are mixed in 101:2000 (mg/mg) ratio and poured into the mold, the mixed solution will be in five After preliminary curing within minutes, it was placed in an oven and vented with nitrogen and a test piece (II)-1 was prepared at a temperature of 150°C/2h. The sample code The names are (II)-1-0.1%, (II)-1-0.5%, (II)-1-1%, (II)-1-3%.

Embodiment 5: Please refer to the third figure, which is a synthesis schematic diagram of norbornene modified nano carbon fiber polydicyclopentadiene composition according to an embodiment of the present invention. First, dicyclopentadiene (DCPD) and four different levels of modified nano-carbon fiber (I)-2 (0.1, 0.5, 1, 3wt%), using a membrane breaking machine to (I)-2/DCPD Shake for 2 minutes to break up the large-scale aggregation phenomenon, and then place it in an ultrasonic oscillating machine to shake for 3~4 hours. After dispersion, first mix Grubbs' second-generation catalyst and dichloromethane (DCM) at room temperature with 1: 100 (mg/mg) ratio is mixed first, and then the prepared catalyst solution and (I)-2/DCPD are mixed at a ratio of 101:2000 (mg/mg) and then poured into the mold, the mixed solution will be divided into five After the initial curing, the test piece (II)-2 was prepared by placing it in an oven and introducing nitrogen gas at a temperature of 150°C/2h. The sample codes are named (II)-2-0.1%, (II)-2-0.5%, (II)-2-1%, (II)-2-3%.

Comparative example: DCPD and three kinds of unmodified nano-carbon fiber (CNF) (0, 1, 3wt%) with different contents are used to shake the CNF/DCPD for 2 minutes with a membrane breaking machine to break the large-scale aggregation phenomenon, and then Place in an ultrasonic oscillating machine and shake for 3~4 hours. After dispersion, first mix the catalyst and methylene chloride (DCM) at a ratio of 1:100 at room temperature, then mix the catalyst solution and CNF. /DCPD is mixed at a ratio of 101:2000 and poured into a mold. The mixed solution will be initially cured within five minutes, then placed in an oven and vented with nitrogen, to prepare a cured product at a temperature of 150°C/2h. The sample codes are named pDCPD, CNF-1%, CNF-3%.

The invention uses DMA (Dynamic Mechanical Analyzer) to test different content of modified nano carbon fiber 0.1, 0.5, 1, 3wt% (based on DCPD) A cured product prepared by dispersing in DCPD. The hardened cured product was made into a test piece with a length of 20 mm, a width of 10 mm, and a thickness of 2 mm. The heating rate was 5° C./min and the frequency was 1 Hz. The storage modulus (Storage Modulus E′) and Tan δ curve were measured. In the modified nano carbon fiber compositions (II)-1 and (II)-2, the 3% Tan δ curve height becomes very small, indicating that the modified nano carbon fiber is introduced compared to the unmodified nano carbon fiber (I)-1 and (I)-2 will make the polymer very hard. As shown in Table 2, the introduction of carbon fiber in DCPD will increase the modulus of the glassy state and the rubbery state, and the two modified nano carbon fiber compositions (II)-1 and (II)-2 are in the modified nano The carbon fiber content of 0.1wt% can be better than the storage modulus of 1wt% of unmodified nano carbon fiber. Its content of 1wt% has the largest lifting amount (1079 to 2274MPa), but it is reduced above 3wt% because it is in the system Although there is a better dispersion, the excess (I)-1 and (I)-2 will cause aggregation with DCPD, leading to two phases (aggregated phase/dispersed phase) in a film leading to a decrease in properties.

The tensile test of the embodiments of the present invention can find that the fracture elongation of the modified (II)-1 and (II)-2 thermosetting materials can maintain a value of more than 4%, and it is the same as the unmodified nano carbon fiber cured product ( CNF-1% or CNF-3%) has better elongation, the data is compiled in Table III; when the tensile strength of the two (II)-2 and (II)-1 is 0.1wt% It can be increased from 19.36MPa to 23.65MPa of pDCPD, and it can be found from Table 3 that when the content is 0.1wt%, the effect of carbon fiber is 1wt%, and the tensile strength of the modified nano carbon fiber is more than 0.5wt%. With this decrease, it is presumed that poor dispersion results in a decrease in tensile strength. Although the above-mentioned modulus may decrease, the overall tensile strength has more excellent mechanical properties than the original pDCPD.

The present invention provides a modified carbon nanofiber-containing polydicyclopentadiene containing norbornene and its preparation method. First, the carbon nanofiber (CNF) is reacted under a specific ratio of nitric acid/sulfuric acid to obtain acidified nanocarbon fiber, and then the SOCl ₂ In the final reaction, two types of surface-modified carbon fibers were formed in the two norbornene structures, which were catalyzed by Grubbs' catalyst to obtain the ring-opening metathesis polymerization (ROMP) of dicyclopentadiene and norbornene. The addition of modified carbon fiber on the surface of norbornene not only increases the dispersibility of nano carbon fiber in dicyclopentadiene, but also improves the mechanical properties of polydicyclopentadiene after curing, and also improves the thermal stability of the material , To make it more widely used in the future.

The above-mentioned embodiments are merely illustrative of the features and effects of the present invention, and are not intended to limit the scope of the essential technical content of the present invention. Anyone who is familiar with this skill can modify and change the above embodiments without departing from the spirit and scope of the invention. Therefore, the scope of protection of the rights of the present invention should be as listed in the scope of patent application mentioned later.

S101-S103‧‧‧Step

S201‧‧‧Step

Claims (10)

A kind of modified nano carbon fiber as formula (I),

Among them, R is the structure of O or NH, n=7-10. A method for preparing modified carbon nanofibers of formula (I) as described in item 1 of the patent application, the steps include: (1) providing a nanocarbon fiber, acidifying the nanocarbon fiber; (2) after acidifying The carbon nanofibers undergo chlorination; (3) The carbon nanofibers after the chlorination react with 5-norbornene-2-methanol or 5-norbornene-2-amine to obtain the formula (I )-1 or modified nano carbon fiber of formula (I)-2,

Among them, n=7-10. As described in item 2 of the patent application scope, a method for preparing modified nanocarbon fiber of formula (I), wherein the acidizing liquid system of step (1) is nitric acid or sulfuric acid. As described in item 2 of the scope of the patent application, a method for preparing modified carbon nanofibers of formula (I), wherein the chlorination liquid system of step (2) is sulfenyl chloride (SOCl ₂ ). A method for preparing modified carbon nanofibers of formula (I) as described in item 2 of the patent application scope, wherein the reaction temperature of step (3) is between 50°C and 80°C. A modified nano carbon fiber composition as in formula (II),

Among them, R is a structure of O or NH. A method for preparing a modified nano-carbon fiber composition of formula (II) as described in item 6 of the patent application scope is to modify the modified nano-carbon fiber of formula (I) as described in item 1 of patent application scope and dicyclopentane Enene, under catalyst catalysis, undergoes ring-opening polymerization reaction to obtain a modified nano carbon fiber composition as formula (II). The method for preparing the modified nano-carbon fiber composition of formula (II) as described in item 7 of the patent application scope, wherein the reaction weight ratio of dicyclopentadiene to the modified nano-carbon fiber of formula (I) is between 100:0.1 Between 100:3. The preparation method of modified nano-carbon fiber composition of formula (II) as described in item 7 of the patent application scope, wherein the catalyst is selected from

,

and

One of the groups formed. The method for preparing a modified nanocarbon fiber composition of formula (II) as described in item 7 of the patent application scope, wherein the temperature of the ring-opening polymerization reaction is between 120°C and 180°C.

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