CH 25 PDF
CH 25 PDF
CH 25 PDF
Ploymer is very large molecule in which very large number of simple repeating structural units
joined together by covalent bond. Here, simple repeating structural units are called monomer.
Example, innumerable molecules of ethene monomer (C2H4) combined with each other in polythene
CH
( 2
CH 2).
Classification of polymers
Classification based on source :
(a) Natural polymers : Polymers present in nature are obtained from plants or animals e.g.
protein, cellulose, starch, nucleic acids, natural rubber. Polymers which is control the life
style of plants or animals known as biopolymers. e.g. starch, protein, cellulose, nucleic
acid.
(b) Synthetic polymers : Polymer which is made in laboratries known as synthetic
polymers. e.g., polythene, nylon, decron etc.
(c) Semisynthetic polymers : Polymers which are formed by chemical reaction with the
polymers present in nature are called semisyntehtic polymers. eg. cellouse diactete is
obtained by acetylalion reaction of cellulose with acetic anhydride in presence of H2SO4.
Explosive cellulose nitrate are formed by nitration of cellulose. Vulcanised rubber
obtained by vulcanisation of natural rubber which is used in manufacture of tyre.
The unit which is repeated sevral times in a polymer is called repeating unit. Number of
repeating unit n in polymer molecule is called degree of polymerisation.
Chain growth and step growth polymer :
Chain growth polymer : This type of polymer is formed by repeated addition of monomer
molecules to the growing chain carrying a reactive intermediate such as a free radical, a carbocation
or a carbanion.
Step growth polymer : In each step a distinct functionalised species are produced by
condensation reaction and each step is independent of each other. Thus, the polymer is obtained is
known as step growth polymer.
637
Some distinguishing points between chain growth polymerisation and step growth polymerisation.
No. Chain growth polymerisation Step growth polymerisation
(i) It is addition polymerisation It is condensation polymerisation
(ii) Monomer is added in growing chain. Monomer form dimer, trimer etc.
by addition in step by step.
(iii) It takes place in presence of intiaters. No intiater is required.
(iv) It is very fast reaction. It is slow reaction.
This type of polymers contain branch in between the long straight chain in their constitution.
e.g., Amaylopectin, PVC polystyrene. Branched polymers have low boiling point and law density.
polymerisation. polymerisation.
(2) Once it get shape it will be not melt. (2) It will become soft on heating and become
(5) It is hard and strong. (5) It is soft and less strong than theomosetting.
(5) These polymers can not obtained again. (6) These polymers can obtained again.
(6) They are insoluble in organic solvent. (7) Some of them are soluble in organic
solvent.
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Properties of polymer substances : Properties of polymers depends upon (i) structure of
molecule in them. (ii) Average molecular mass of them. If number of molecules are more with higher
molecular mass in any polymer then the boiling points, hardness of them is more. If number of
molecules are more with less molecular mass in any polymer then the density, boiling point and
hardness of them are less. In this type of polymers degree of polymerisation is high than its called
HDP and If degree of polymerisation is less than it is called LDP. Hard and durable instruments are
made from HDP while soft and low weight instruments are made from LDP.
Linear polymers like polyamide and polyester are used as synthetic Fibers. Synthetic fibers can
not combined with molecule of water by hydrogen bond in comparition of cotton. So, the cloth is
eaisyly dry which is formed by polyaminde and polyester fiber.
Changing in properties of polymers : For changing properties of polymer for different uses,
some substances are added in them.
(i) Inorganic substances like TiO2, BaSO4, CaCO3, SiO2 are added during polymerisation
reaction to introduced heardness, density in some polymer. These substabce are called
filler.
(ii) In some polymers organic substance like Trycresyle phosphate, glycerine phthalate,
tertiary butyl phthalate, olic acid are added to introduce property of softness. These
substance are called plasticizer.
(iii) In some substances, made from polymer crack observed in the prsence of sunlight. So
that, the life of it decreases. If phenol, cresol, quinole, carbon-black are added in that
polymers, the effect of sunlight is not observed. So, the degradation of this polymers can
be stopped. This organic substance are called antioxidant.
Cheracteristics of Polymers :
(i) Different instruments are formed easily from polymer and their weight is less.
(ii) Their is no effect of atmosphere and moisture on polymers. Whereas, their is harmfull
effect on metal, wood, leather, cotton cloth etc.
(iii) Different instruments can be prepared from polymer because of some properties like heat
resistant and non-conductor of electricity.
(iv) There is no effect of chemicals and insects on polymers.
(v) By adding proper useful substances in some polymer, we can change the properties.
(vi) Raw material is easily available and cheap for manufacturing of polymer.
Initiater Ethene
In
( CH2 CH2
) CH2 CH2
·
}}}}}}}
nCH = CH
m2 2
· ·
In
( CH2 CH2
)n CH2 CH2 + CH2 CH2
( CH2 CH2
)n In
In
( CH2 CH2
)n CH2 CH2 CH2 CH2 ( CH2 CH2
)n In
Polythene Polymer
Cationic addition polymerisation
Cationic reactive intermediate is produced by the use of initiators like acid in the first step of
this reaction at proper temperature and pressure. This reactive intermediate combined with many
`other monomers containing electron releasing group and double bond step by step. At the end
polymer is obtained in the presence of base.
CH 3 CH 3 CH 3
| |
m
|
+
H + CH2 = C CH 3
– C CH 2 Cm
| | |
CH 3 CH 3 CH 3
Initiator isobutylene
CH 3 CH 3 CH 3
| | |
CH 3 – C – CH 2 – C + + nCH 2 C m
| | |
CH 3 CH 3 CH 3
Initiater styrene
+
H2N – CH2 – CH – CH 2 – CH – CH 2 – CH H
H2N – CH 2 – CH – CH 2 – CH2
n
polystyrene polymer
Condensation polymerisation
In this type of polymerisation condensation reaction repeatedly takes place between two
different type of monomers possessing two similar functional groups. As a result of this condensation
polymerisation reaction, simple molecules such as water, ammonia or alcohol are removed. Nylon 66
is obtained from hexamethylenediamine and adipic acid and terylene is obtained from dimethyl
terpthalate and ethyleneglycol monomers.
Natural rubber
Natural rubber is polymer of isoprene. In natural rubber all the double bonds have cis
sterochemistry. So, natural rubber is cis poly-isoprene. By making incision in the trunk of rubber
trees, the colloidal suspension of milky rubber in water, called latex is obtained.
CH3 H H
CH 2= C – CH = CH2 OR C–C
H2C CH2
2-methylbuta -1, 3 diene (cis-Isoprene)
(Isoprene)
CH3 H CH3 H
C=C CH2 CH2 C=C
CH 2 CH2 C=C CH2 CH2
CH3 H
Natural rubber [cis 1, 4-polyisoprene]
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Limitation of Natural rubber
(i) Their efficiancy is not like plastic or they does not possess elastic properties.
(ii) They become dry at law tempareture and become soft at high tempareture. They can be
used at 10° C to 60° C temperature.
(iii) Its tensile strength is less. (Only 200 kg cm2)
(iv) Its water adsorbtion capacity is very high.
(v) They are oxidised by air easily.
(vi) Its resistance against tear and wear is less and less durable.
(vii) When force is applied it changes shape.
Vulcanisation
In 1893, Charles Goodyear discovered that mixture of natural rubber and sulphur when heated at
temperature 373 to 415 K its physical properties can be necessarily imporved to a spectacular manner.
This process is called vulcanisation. Thus added sulphur combined nearly to double-bond of
chain in natural rubber.
CH3 CH3
| |
..... CH2 C = CH CH2 CH2 C = CH CH2 .....
CH 3 CH 3
}}}}}}}}
+ S /heat m
vulcanisation
| |
..... CH 2 – C – CH – CH 2 – CH 2 – C – CH – CH 2 –.....
| | | |
S S S S
| | | |
..... CH 2 – C – CH – CH 2 – CH 2 – C – CH – CH 2 – .....
| |
CH 3 CH 3
(Vulcanised rubber)
Thus, vulcanisation make a substance strong due to cross linkage. Strength of vulcanised
rubber depended upon proportion of sulphur which is added during the reaction. eg. 5 % sulphur is
present in rubber which is used in tyres but 30 % sulphur is present in rubber which is used to
making battery-cases. Stretching speed of vulcanised rubber and its property of regains to its original
shape depend on cross linkage of sulphur.
S S
S S
S S s s
S Strech S
S Relax S
S S
S s
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Molecular mass of polymers
(i) Number average molecularmass (M n )
d
4 Ni Mi
i 1
Mn =
d
4 Ni
i 1
N1M1 + N 2M 2 + N3M3
= N1 + N 2 + N3
N1M12 + N 2M 22 + N3M 32
= N M +N M +N M
1 1 2 2 3 3
Here, N1, N2, N3 is number of molecules havig molecular mass of M1, M2, M3 respectively.
Example : In a sample of polymer substance 30% molecules have 20,000 molecular mass,
40% molecules have 30,000 molecular mass and remaining molecule have 60,000 molecular mass.
Find out M w and M n .
Solution :
(30 ×20000) + (40 × 30000) + (30 × 60000)
Mn =
(30 + 40 + 30)
600000 + 1200000 + 1800000
=
100
3600000
= 36000
100
30 (20000) 2 + 40 (30000)2 + 30 (60000)2
Mw =
(30 × 20000) + (40 × 30000) + (30 × 60000)
Natural polymers are generally monodispersed, therefore PDI = 1. It means that M w = M n . Synthetic polymers
are always polydispersed, so PDI > 1. It means that M w > M n . Calculation of number average molecular mass
( M n ) in any polymer is depends upon the number of molecules present in the polymer sample.
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Molar mass of single molecule present is polymer substance can be calculated by light
scattering, chromatographic and ultracentrifuge methods.
Biopolymers
The polymer substances present in the nature such as polysaccharide, protien and nucleic acid
which are very useful for the human life are called biopolymers.
Synthetic polymer substances shows inertness towards the enviromental process. In every day
use synthetic polymer substances can not be easily degraded. So it is not converted in to life
essential products. These type non-biodegradable polymer waste is an acute problem. As a result
environmental problems have been created.
The degradation of biopolymers which takes place mainly by enzymes, hydrolysis. There is no
issue of its disposal. So synthetic biodegradable polymers can be synthesised, which are convenient to
living system. Using some aliphatic substances as monomer, many polymers are industrially prepared
and some polymers of them possesses biodegradable properties.
}}}}}}}}m
– O – CH – CH2 – COO – CH – CH2 – CO –
Polymerization | |
– nH O2 CH3 CHH2– CH3
n
(PHBV)
PHBV is used in special types of packaging and in orthopaedic devices and in capsules for
filling controlled release of drugs. When a drug is enclosed in a capsule of PHBV, it is released only
when the the polymer is degraded in the body. PHBV also undergoes bacterial degradation in
enviornmental condition.
PGA and PLA are prepared industrially. Dextran is the first biodegradable polyestester polymer
used for post operative stitches.
(A) CH2 = CH2 (B) CH2 = CCl2 (C) CHCl = CHCl (D) CH2 = CHCl
16. Which of the following is an example of thermosetting polymer ?
(A) Polythene (B) Neoprene (C) PVC (D) Bakelite
17. With whom phenol is reactaed Backelite obtained ?
(A) Polythene (B) Acetyle (C) Formaldihyde (D) Chlaro Benzene
18. Which catalyst is used in preparation of polythene by ziegler-Natta method ?
(A) Lithium tetrachloride and tryphenyl Aluminium
(B) Titanium tetrachloride and triethyl aluminium
(C) Titanium
(D) Titanium isoperoxide
19. Which of the following pair is not true ?
(A) Terylene : Condensation polymer of terphtalic acid and ethylene glycol
(B) Teflon : Cross linking stable polymer prepared from phenol and formaldehyde.
(C) Glyptal : It is homopolymer of methyl metha crylate
(D) Synthetic rubber : It is condensation polymer of butadiene and styrene.
20. Which is the product of Addition polymerisation ?
(A) PVC (B) Nylon (C) Terylene (D) Polyamide
21. Which is the natural Bio-polymer ?
(A) Teflon (B) Nylon-66 (C) Rubber (D) DNA
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22. Tetrafluoro ethene is monomer of which polymer ?
(A) Ethelene (B) PVC (C) Teflon (D) Nylon-66
23. Which of the following is chain polymer ?
(A) Bakelite (B) Ethelene (C) Teflon (D) PVC
24. What is an ebonixe ?
(A) Natural rubber (B) Synthetic rubber
(C) Hard valcanized rubber (D) Poly-propene
25. Bakelite is obtained by reaction between which substances ?
(A) Urea and formaldehyde
(B) Phenol and formaldehyde
(C) Tetra methylene glycol and hexamethylisocynate
(D) Ethylene glycol and dimethylterphatalate.
26. High molecular mass present in ...... polymer.
(A) elastomer (B) fiber
(C) thermoplastic (D) thermosetting plastic
27. PMMA is polymer of which monomer ?
(A) methyl methacrylate (B) methacrylate (C) methylacrylate (D) ethylacrylate
28. Bekelite is obtained by reaction between phenol and formaldehyde, then in first step the
reaction between two substances show example of ?
(A) aromatic electrophilic substitution reaction
(B) aromatic nucleophilic substitution reaction
(C) free dradical reaction
(D) aldol reaction
29. Glyptal polymer is obtained by reaction between glycerol and which substance ?
(A) melonic acid (B) phthalic acid (C) maleic acid (D) acetic acid
30. ...... is monomer of Teflon polymer.
(A) Difluoro ethene (B) Mono fluoro ethene (C) Tetra fluoro ethene (D) Tetra chloro ethene
31. Which polymer is not addition polymer ?
(A) Polythene (B) Polystyrene (C) Neoprene (D) Terylene
32. Which polymer is used in manufacturing of non-stick kitchen vessels ?
(A) PVC (B) Polystyren
(C) Polyethene (D) Polytetrafluoroethene
33. Which is the example of addition polymer ?
(A) Buna-S (B) Bakelite (C) Nylon-6 (D) Melamine
34. Which of the following is copolymer ?
(A) Nylon-6 (B) Nylon-6 6 (C) PMMA (D) Polyethene
35. Which polymer possesses isoprene monomer ?
(A) Natural rubber (B) Nylon-6, 6 (C) Polyethene (D) Deoron
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36. Which polymer is not synthetic ?
(A) Polyethene (B) PVC (C) Nylon (D) Cellofen
37. Which of the following is not true for polymer ?
(A) Polymer does not possesses any type of electric charge.
(B) Polymer have high density.
(C) They can scatter of light
(D) They have low molecular mass
38. In which class, polymer can be classified on the basis of preparation method ?
(A) Only Addition polymer (B) Only condensation polymer
(C) Co-polymer (D) (A) and (B) Both
39. Natural rubber is polymer of which monomer ?
(A) butadiene (B) ethyne (C) styrene (D) isoprene
40. Terlyene is condensation polymer of ethelen glycol and ...... ?
(A) benzoic acid (B) acetic acid (C) terephthalic acid (D) salicylic acid
41. Zieglar-Natta catalyst is ...... .
(A) K[pyCl3 (C244] (B) (ph3p)3 RhCl (C) Al2 (C2H5)6 + TiCl4 (D) Fe(C2H5)2
42. Preparation of Nylon-66 is possible by condensation of HMDA with,
(A) phenol (B) benzaldehyde (C) adipic acid (D) sucsinic acid
43. The reaction of heating of natural rubber with sulphur is known as ......
(A) galvanization (B) vulcanisation (C) nitration (D) sulphonation
44. Terylene is obtained by polymerisation of terepthelic acid and ......
(A) ethelene glycol (B) phenol (C) ethanol (D) catacol
45. Teflon, styrene and neoprene all are ...... .
(A) co-polymer (B) condensation polymer (C) homopolymer (D) monomer
46. Which type of intermolecular attraction force are present in Nylon-66 ?
(A) Van der waals (B) hydrogen bond
(C) dipolar-dipolar attraction (D) none of these
O
&
(B) Nylon-66 : [ NH ( CH2 ) 6 NHCO – ( CH2 ) 4 C – O ] n
CH3
(D) PMMA CH2 C n
COOCH3
CH3
55. – C – CH2–n is obtained from which monomer ?
CH3
CH
¥ – CH 2 – CH –µ | 3 CH2 - CH -
¦ | ¶ CH2 – C– ¥– CH 2 – CH –µ
(A) ¦ CN ¶· (B) | (C) (D)
§ ¦ | ¶
n COOCH3 COOC 2H5 n ¦ Cl ¶·
n § n
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70. From which, Nylon fibers are prepared ?
77. Which substance is used for making a strong rubber for tyres ?
(A) Butadiene and Acrylonitrile (B) Ethelen glycol and Terepthelic acid
(C) Hexa methylene diamine and Adipic acid (D) Melamine and Formaldehyde
79. The value of number average number molecular mass and weight average molecular mass is
30,000 and 40,000 respectively then, what is the value of PDI ?
81. Thermosetting polymer bakelite is obtained by the reaction of phenol with ...... .
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83. Co-polymer Buna-N is prepared from which monomer ?
(A) CH2 = CH CN and CH2 = CH C = CH2
|
CH3
Cl
|
(B) CH2 = CH Cl = CH2 and H2C = CH CH = CH2
¤N M 2
¤N M ¤N M 2
¤M N
(A) M n
¤N (B) Mn
¤N
i i
¤N M ¤N
i i
(C) M n i i (D) M n i i
i i i i i
87. In one sample 30% molecules have 20,000 molecular mass and 40% molecules have 30,000
molecular mass and other have 60,000 molecular mass then what is the value of Mn is?
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111. Reyon fibers are made from ......
(A) polymethelene (B) polyester (C) cellulose (D) styrene
112. Natural rubber is ......
(A) polymer of buta-1,3-diene (B) polymer of ethylene
(C) polymer of 2-methyl-1, 3-butadiene (D) polymer of styrine
113. ...... is the product of addition polymerisation reaction.
(A) PVC (B) Nylon (C) Terylene (D) Polyamide
114. Which of the following is not a polymer ?
(A) sucrose (B) catalyst (C) starch (D) teflon
115. In present time, which one is used in coating of tyres ?
(A) Terylene (B) Polythene (C) Polypropen (D) Nylon-6
116. Protein is ...... .
(A) polyester (B) polyamide (C) polythene (D) polyanhydride
117. Which of the following polymer is used in valve packing ?
(A) Teflon (B) Terylene (C) Polystyrene (D) Polythene
118. What percentage of sulphur present valcanised rubber used in manufacturing of tyre ?
(A) 5 % (B) 3 % (C) 30 % (D) 55.0 %
119. ...... is used in preparation of plastic crokery of household.
(A) Melamine and tetrachloroethan (B) Melenoied acid and hexamethelenamine
(C) Melamine and vinyl acetate (D) Melamine and formaldehyde
120. The repeating unit in PTFE is
Answers : 1. (C), 2. (D), 3. (D), 4. (D), 5. (A), 6. (C), 7. (B), 8. (D), 9. (A), 10. (B),
11. (B), 12. (C), 13. (C), 14. (A), (15. (A), 16. (D), 17. (C), 18. (B), 19. (B),
20. (A), 21. (D), 22. (C), 23. (D), 24. (C), 25. (C), 26. (D), 27. (A), 28. (A),
29. (B), 30. (C), 31. (D), 32. (D), 33. (A), 34. (B), 35. (A), 36. (D), 37. (D),
38. (D), 39. (D), 40. (C), 41. (C), 42. (C), 43. (B), 44. (A), 45. (C), 46. (B),
47. (A), 48. (D), 49. (B), 50. (A), 51. (D), 52. (B), 53. (B), 54. (C), 55. (A),
56. (A), 57. (A), 58. (C), 59. (A), 60. (B), 61. (A), 62. (A), 63. (A), 64. (B),
65. (C), 66. (C), 67. (A), 68. (C), 69. (A), 70. (A), 71. (B), 72. (A), 73. (D),
74. (C), 75. (A), 76. (B), 77. (D), 78. (C), 79. (B), 80. (B), 81. (B), 82. (D),
83. (D), 84. (A), 85. (B), 86. (B), 87. (B), 88. (B), 89. (D), 90. (D), 91. (B),
92. (C), 93. (D), 94. (C), 95. (A), 96. (B), 97. (B), 98. (C), 99. (D), 100. (A),
101. (D), 102. (C), 103. (B), 104. (D), 105. (A), 106. (B), 107. (A), 108. (A),
109. (D), 110. (D), 111. (C), 112. (C), 113. (A), 114. (A), 115. (D), 116. (B),
117. (A), 118. (A), 119. (D), 120. (A).
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