Polymers Flashcards

1
Q

Branch chain polymer eg

A

amylopectin, glycogen, low density polyethylene and all

vulcanised rubbers.

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2
Q

Condition for condensation polymerization

A

For condensation polymerisation, monomers should have at least two functional groups.

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3
Q

What is zieglar natta catalyst and what kind of polymers does it give and what kind of polyethelene is formed high/low density

A

Ziegler-
Natta catalyst [(C2H5)3 Al] and TiCl4

zieglar catalysts give linear, stereoregular polymers

High density polyethylene is prepared using a Ziegler-Natta catalyst.

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4
Q

What are elastomers, what kinda forces is present in it, and what are the eg

A

An elastomer is a plastic that stretches and then reverts back to its original shape.

Very weak Van Der Waal forces are present in between polymeric chains.

Examples are vulcanized rubbers.

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5
Q

How are individual chains in fibres held together

A

Fibres are linear polymers in which the individual chains of a polymer are held together by hydrogen bonds and / or dipole-dipole attraction.

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6
Q

Fibres have _____ tensile strength,_____ MP, _____ solubility, ____ elasticity

and reason ?

A

high tensile strength, high melting point, low solubility, least elasticity

reason- strong intermolecular forces of attraction and highly ordered strucutre

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7
Q

Eg of fibres

A

Examples are cellulose, nylon, terylene, wool, silk etc.

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8
Q

Thermo plastic eg

A

polyethene polypropylene, polystyrene,

polyvinyl chloride. teflon etc.

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9
Q

what is thermosetting polymers?

A

Polymers which become hard on heating are called thermosetting
polymers.

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10
Q

What kinda polymers are cross linked polymers

A

Thermosetting polymers are cross- linked polymers.

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11
Q

Eg of thermo setting polymers

A

Examples are : phenol formaldehyde resin, urea-formaldehyde resin,
melamine - formaldehyde resin.

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12
Q

Natural rubber str, name,common name in normal and polymer form

A

Natural rubber is a polymer of 2-methyl-1.3-butadiene

common name- isoprene or cis-polyisoprene in polymer form

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13
Q

the difference between gutta purcha and the cis-polyisoprene.

A

gutta purcha and cis poly isoprene have same structure but just the gutta purcha is trans and cis polyisoprene is cis

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14
Q

Gutta purcha str

A

wrong

its trans poly isoprene

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15
Q

gutta percha is harder/softer and more flexible/brittle

A

harder and brittle

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16
Q

Gutta purcha use

A

It is the filling material that

dentists use in root canal treatment.

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17
Q

Why are rubber vulcanized?!

A

Natural rubber becomes soft at
high temperature (>335 K) and brittle at low temperatures (<283
K) and shows high water absorption capacity. It is soluble in nonpolar solvents and is non-resistant to attack by oxidising agents.
To improve upon these physical properties, a process of
vulcanisation is carried out

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18
Q

how are rubber vulcanised

A

This process consists of heating a mixture of raw rubber with sulphur and an appropriate
additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.

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19
Q

What are synthetic rubber

A

Polymers of 1,3 - butadienes are called synthetic rubbers

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20
Q

forms ____ after polymerization

A
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21
Q

Whats the polymer called if G=Cl in

A

neoprene

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22
Q

how is the conversion of chloroprene to neoprene carried out!? (catalyst?)

A

zieglar natta catalyst

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23
Q

Where are neoprene used and what are they resistant to

A

It is non - inflammable and is used for making automobile and refrigerator parts, hoses for petrol and oil containers, insulation of electric wires, and conveyor belts.

Neoprene is more resistant to the action of oils, gasoline, and other hydrocarbons. It is also resistant to sunlight, and oxygen. ozone and heat.

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24
Q

Buna S also called ___ and its full form and what is it made of

A

SBR:- styrene butadiene rubber

Buna-S rubber is a copolymer of three moles of butadiene and one mole of
styrene.

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25
Q

Styrene structure

A
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26
Q

structure buna-S

A
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27
Q

Buna S is resistant/not resistant to wear and tear

A

It is extremely resistant to wear and tear

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28
Q

what does Buna S needs to start its formation reactioN!? and also give the reaction

A

Nascent Oxygen

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29
Q

use of Buna-S

A

used in the manufacture of tyres and other mechanical rubber goods.

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30
Q

Buna N is formed by

A

It is obtained by co-polymerisation of butadiene and

acrylonitrile

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31
Q

Acrylonitrile str

A
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32
Q

structure of Buna-N

A

C=C-CN

1,3 buta diene

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33
Q

Where is buna N mostly used in

A

It is very rigid and is very resistant to action of petrol, lubricating oil and many organic solvents. It is mainly used for making fuel tanks.

34
Q

Nylon is used for what

A

Nylon is used for all synthetic fibres forming polyamides, i.e.,having a
protein like structure.

35
Q

Nylon x y what does x,y represents

A

x determines the number of C atoms in amine

y determines the number of C atoms in acid

36
Q

Nylon 66 is obtained by hydrogenation/condensation

A

condensation

37
Q

Nylon 66 str and is made by

A
38
Q

Nylon 6 str and what it ismade of

A

made by caprolactum

39
Q

Low density polyethylene is manufactured by and what kind of polymerisation does it has?!

A

It is manufactured by heating ethylene at high temperature and high pressure and in the presence of traces of oxygen or peroxide initiator

This polymerisation is a free radical polymerisation.

40
Q

are low density polyethylene branches structure or linear?

A

branched

41
Q

why do low density polythenlene have less densityq

A

because they have branched strucutre

42
Q

use of low density polyethelyne

A

It is a transparent polymer of moderate tensile strength and high toughness. It is widely used as a packing material and as insulation for electrical wires and cables.

43
Q

High density polyethylene is prepared by

A

It is prepared by the use of Ziegler - Natta catalyst at high temperature but at low pressure

44
Q

what kind of structure does high denisty polythelene has? branched or linear

A

linear

45
Q

use of high-density polyethylene

A

It is used in the manufacture of containers ( buckets, tubes), housewares, bottles, and toys.

46
Q

Melamine polymer is also known as and melamine polymer srtr

A

Melamine - formaldehyde resin

47
Q

Bakelite is also known as and how is it formed

A

Phenol-formaldehyde resins

obtained by the reaction of phenol and formaldehyde in the presence of either an acid or a basic catalyst.

48
Q

novolac and bakelite structure

A
49
Q

Dacron is polyethylene/polyester

A

polyester

50
Q

Dacron str

A
51
Q

Eg of biodegradable polymers

A

PHBV:- Poly- hydroxybutyrate-CO-β-Hydroxyvalerate

NYLON-2-NYLON-6

52
Q

Teflon’s monomer

A

tetrafluoroethylene

53
Q

PVC’s monomer

A

vinyl chloride

54
Q

Vinyl cyanide is also called as and monomer of

A

poly acrylonitrile or orlon

55
Q

Buna N is a organic or synthetic polymer!?

A

synthetic

56
Q

which polymer is fully flourinated?

A

teflon

57
Q

eg of semi-synthetic polymers

A

cellulose acetate and cellulose nitrate

58
Q

what kind of monomers are used in addition polymerization or chain growth polymerization

A

unsaturated compounds

59
Q

eg of free radical generating initiator

A

benzoyl peroxide

acetyl peroxide

tert butyl peroxide

59
Q

What Does the process of ethene to polythene consists of?

A

it consists of heating or exposing to light a mixture of ethene with a small amount of benzoyl peroxide initiator

60
Q

how is teflon formed?

A

teflon is manufactured by heating tetrafluoroethylene with a free radical or persulphate catalyst at high pressures

61
Q

where are teflon used?

A

its used in making oil seals and gaskets and also used for non-stick surface coated utensils

62
Q

what can be a substitute for wool?

A

Polyacrylonitrile is used as a substitute for wool in making commercial fibres as orlon or acrilan

63
Q

how are polyacrylonitrile formed

A
64
Q

condensation polymerization requires

A

a bifunctional or trifunctional monomeric units

65
Q

how is dacron formed?

A
66
Q

formation of terylene and Dacron is an eg of which kind of polymerisation

A

condensation polymerization

67
Q

why does nylon has high tensile strength

A

hydrogen bonding

68
Q

why does nylon have crystalline nature

A

intermolecular forces like hydrogen bonding. These strong forces also lead to close packing of chains and thus impart crystalline nature.

69
Q

how is nylon 6 oobtained?

A

heating copralactum with water at high temperature

70
Q

polyesters are

A

These are the polycondensation products of dicarboxylic acids and diols

71
Q

eg of polyesters are

A

Dacron or terylene is the best-known example of polyesters

72
Q

whats a initiator/catalyst in dacron formation?

A

zinc acetate-antimony trioxide

73
Q

melamine formaldehyde polymer formation

A
74
Q

Copolymers have properties quite different from homopolymers

true or false

A

trure

75
Q

what can be good substitute for natural rubber? and why

A

butadiene - styrene copolymer is quite tough and is

a good substitute for natural rubber

76
Q

why does natural rubber stretch?

A

the polymer chains are held together by the weak intermolecular forces. These weak binding forces permit the polymer to be stretched

77
Q

what allows rubber to retract to its position

A

A few ‘crosslinks’ are introduced in between the chains, which help the polymer to retract to its original position after the force is released.

78
Q

rubber latex cause which type of solution?

A

colloidal dispersion

79
Q

how are buna N formed?

A

Buna–N is obtained by the copolymerisation of 1, 3 – buta–1, 3–diene and acrylonitrile in the presence of a peroxide catalyst

80
Q

how are PHBV formed?

A