Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Q1 Pollyyyy > BASIC TYPES OF POLYMERIZATIONS > Flashcards

BASIC TYPES OF POLYMERIZATIONS Flashcards

1
Q

a process through
which a large number of monomer
molecules react together to form a
polymer

A

Polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The macromolecules
produced from a polymerization may
have a _______________ structure.

A

linear or a branched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In _______, W. H. Carothers suggested a
classification of polymers into two
groups

A

1929
condensation (step-growth)
and addition (chain-growth) polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

a process by which monomer
units are attached one at a time in chainlike
fashion to form a linear molecule

A

Chain-growth polymerization or addition
polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In chain-growth polymerization or addition
polymerization, the composition
of the resultant product molecule is __________ of that of the original reactant monomer.

A

an exact
multiple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

growth of a polymer chain proceeds exclusively by
reaction(s) between **monomer(s) and reactive
site(s) **on the polymer chain with regeneration of
the reactive site(s) at the end of each growth step

A

chain reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Chain-growth polymerization involves the addition of __________ to a rapidly growing chain

A

unsaturated
molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The most common unsaturated compounds that undergo chain-growth polymerization are

A

olefins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

chain growth olefins, vinyl monomer example

A

image5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Chain-growth polymerization is a polymerization
technique where unsaturated monomer molecules
add onto the ________on a growing polymer chain ____________.

A

active site , one at a time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

There are a ________ number of these
active sites at any moment during the polymerization which gives this method its key characteristics

A

limited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The growing polymer in chain-growth polymerization is a __________, and polymerization proceeds via ___________

A

free radical, chain
mechanism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

It is induced by the addition of ________________ or by ionic initiators.

A

-freeradical-forming reagents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

It involves three fundamental steps

A

initiation,
propagation, and termination.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Growth centers can either be _____________________ in nature—
depending on the kind of initiator
system used.

A

ionic
(cationic or anionic), free radical,
or coordinational

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Based on the nature of the growth centers, chaingrowth polymerization is further
classified as

A
  1. Free-Radical polymerization
  2. Cationic polymerization
  3. Anionic polymerization
  4. Coordination or stereoregular
    polymerization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A chain
polymerization in which the
kinetic
-chain carriers are
radicals.

A

Free Radical
Polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

a method of
polymerization by which a
polymer forms by the successive
addition of free
-radical building
blocks (repeat units).

A

➢ Free
-radical polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

can be formed by
a number of different
mechanisms, usually involving
separate initiator molecules

A

Free radicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

1st step in free-radical polymerization wherein there is an active monomer

A

❑ Initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

2ndstep in free-radical polymerization wherein there is a growth of the active
(free-radical) chain by sequential
addition of monomers

A

❑ Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

3rd step in free-radical polymerization wherein active chain give
the final polymer product.

A

❑ Termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

involves the acquisition of an
active site by the monomer

A

Initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

This may occur spontaneously by the** absorption of
heat, light (ultraviolet and visible), redox
reagents, electricity, high-energy
radiation, etc. that is any process that
creates the essential free radicals.**

A

Initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

initiation of free-radical
polymerization is brought about by the
addition of small quantities of
compounds called

A

initiators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Typical initiators include

A

peroxides, azo
compounds, Lewis acids, and organometallic
reagents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

usually a **weak organic compound **
that can be decomposed thermally or by
irradiation to produce free radicals, which are
molecules containing atoms with unpaired
electrons.

A

initiator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

example of organic
compounds that can be decomposed thermally
to produce free radicals.

A

Dialkyl peroxides (ROOR)
diacylperoxides (RCO-O-O-CO-R)
hydroperoxides (ROOH)
azo compound (RN>NR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

example of commonly used free-radical
initiator

A

Benzoyl peroxide azobisisobutyronitrile
dit-butylperoxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Initiation in a free-radical polymerization consists of two steps

A
  1. dissociation of the initiator to form two radical species
  2. addition of a single monomer molecule to the initiating radical (the association step).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

On heating, benzoyl peroxide decomposes to give

A

two free
radicals
(image 11)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

(image 11)

what is the active site

A

the electrons in the oxygen–oxygen bond are unpaired and become the
active site.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

R representing a generalized ____________, the free radical can
be written R

A

organic chemical group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

initiation step usually includes the addition of the ___________________

A

first monomer molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

In this initiation reaction the free radical attacks the monomer and adds to it. The double bond is
__________, and the _________ reappears at the far end

A

broken open , free radical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Chain initiation involves the __________ of a radical initiator molecule (I) which is
easily dissociated by heat or light into two free radicals (2 R°).

Each radical R°
then adds a first monomer molecule (M) to start a chain which terminates with a
monomer activated by the presence of an ____________ (RM1°).

I → 2 R°
R° + M → RM1°

A

dissociation , unpaired electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Involves the linear
growth of the polymer chain by
the sequential addition of
monomer units to this active
growing chain molecule

A

Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

On the addition of each monomer,
the free radical moves to the

A

end
of the chain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Chain growth is relatively rapid;
the period required to grow a
molecule consisting of say , __________
repeat units in on the order of ____________ s.

A

1000 , 10-2
to 10-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

a reaction of an active center on the
growing polymer molecule, which
adds one monomer molecule to
form a new polymer molecule
(RM1°) one repeat unit longer.

A

Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

RM1° + M → RM2°
RMn° + M → RMn+1°

A

Propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

**active center **remains an atom with
an unpaired electron.

The addition of the second monomer and a
typical later addition step

A

radical polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

due to annihilation of the radical center of the propagating chain.

A

Termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

The termination step involves the reaction of any two free radicals with each other, either by

A

combination or disproportionation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Two propagating chains are terminated when two radicals combine to form an electron-pair (covalent) bond

A

combination (or coupling)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

reaction of the unpaired electrons of two chains to
form a covalent bond between them

A

Combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

product is a single polymer
molecule with the combined length of
the two reactant chains:
RMn° + RMm°→ Pn+m

A

Combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

A pair of radicals can form two new molecules

A

disproportionation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

a disproportionation termination step involves two growing molecules that react to from
two

A

“dead chains”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

complicated step in which two growing polymer
chains are rendered inactive.

A

a disproportionation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

transfer of a hydrogen atom from one chain to the
other, so that the two product chain
molecules are **unchanged in length **but
are no longer free radicals

RMn° + RMm° → Pn + Pm

A

Disproportionation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

a growing polymer chain is deactivated or terminated
by transferring its growth activity to a previously inactive species

A

Chain Transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

additional step usually involved in a free-radical polymerization

A

Chain Transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

a step in which the growing polymer chain RMn°
takes an atom X from an inactive molecule XY, terminating the growth of the polymer chain

RMn° + XY → RMnX + Y°.

A

Chain transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

RMn° + XY → RMnX + Y°.

The Y fragment ls a __________ which adds more monomer M
to form a new growing chain YMn°

A

new active center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

can be categorized according to the nature
of the growing polymer centers, which yields the classifications
cationic polymerization and anionic polymerization.

A

Ionic polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

involve chain carriers or reactive centers that
are organic ions or charged organic groups

A

Ionic polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

an
ionic polymerization in which the kinetic-chain
carriers are cations.

A

Cationic polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

___________ is a type of chain growth
polymerization in which a cationic initiator transfers
charge to a monomer, which then becomes _______________. This reactive monomer goes on to react similarly with other monomers to form a polymer.

A

Cationic polymerization , reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

The types of monomers necessary for cationic
polymerization are limited to __________ with ________________

A

alkenes , electrondonating substituents and heterocycles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

The growth center in this class of ionic
polymerizations is cationic in nature.

A

Cationic
Polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

polymer cation adds on the monomer
molecules to it sequentially, just as the
polymer radical adds on the monomer in
radical polymerization.

A

Cationic
Polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

a true
catalyst that is restored at the end of the
polymerization and does not become
incorporated into the terminated polymer
chain

A

Cationic
Polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

The initiation of the polymerization is accomplished by catalysts that are _________________.

A

proton donors (e.g.,protonic acids such as H2SO4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Typical catalysts that are effective for cationic
polymerization include

A

AlCl3
AlBr3
BF3
TiCl4
SnCl4

sometimes H2SO4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

exception of H2SO4,
these compounds are all _________________.

A

Lewis acids with strong
electron-acceptor capability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

To be effective, H2SO4 (lewis acids) catalysts generally require the presence of a Lewis base such as water, alcohol, or acetic acid as a __________

A

cocatalyst.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

The monomer molecules act like _____________ and react with the catalyst, giving rise to polymer ions.

A

electron donors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

The successive addition of the monomer to the polymer ion is the

A

propagation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Monomers that polymerize readily with these catalysts include

A

isobutylene
styrene
α-methylstyrene
vinyl alkyl ethers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Cationic polymerizations proceed at _______________
.

A

high rates at low temperatures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

For example, the polymerization at –100°C of isobutylene with BF3 or
AlCl3 as catalysts yields, within a few seconds, a polymer with _______________________

A

molecular weight as high as 10^6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

polymerization of isobutylene with BF3 as the
catalyst procedure

A

(image 28 & 29)

  • Boron Triflouride (catalyst) react with Water (cocatalyst) to produce Catalystcocatalyst
    complex
  • Catalystcocatalyst complex react with isobutylene
  • Isobutylene carbonium ion produced with gegen ion (Catalystcocatalyst complex without H+ outside)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Termination occurs either by ______________ to yield a polymer molecule with an unsaturated terminal unit and the original complex or through __________.

A

rearrangement of the ion pair
transfer to a monomer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

in
which the kinetic
-chain carriers are anion

A

An ionic polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

a form of chain-growth polymerization or addition
polymerization that involves the
polymerization of monomers initiated with
anions.

A

An ionic polymerization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Anionic polymerizations are chain
-growth
processes in which the active center to which
successive monomers are added is a __________ that is associated with a ________________

A

negative ion
positive counterion

77
Q

The _________________ between the
macromolecular anion and its counterion
depends on the nature of the respective ions and the medium in which the polymerization is proceeding

A

degree of interaction

78
Q

While initiators for anionic polymerization are all _________ of varying base strengths, the initiator type required for a particular polymerization depends on the ease with which an anion can be formed from the monomer

A

electron donors

79
Q

The initiator in an anionic polymerization may be any ____________, including Grignard reagents and other ________________ like n-butyl (n-C4H4) lithium

A

strong nucleophile
organometallic compounds

80
Q

In general, the strength of the base required to initiate polymerization ______________ with increasing electronegativity of the
substituent on the monomer

A

decreases

81
Q

commonly used initiator systems
for anionic polymerization

A
  1. Alkali metals and alkali metal complexes (Na, K, Li, and their stable complexes with
    aromatic compounds, liquid ammonia, or
    ethers
  2. Organometallic compounds (butyl lithium,
    boron alkyl, tetraethyl lead, Grignard reagent)
  3. Lewis bases (ammonia, triphenyl methane,
    xanthene, aniline)
  4. High-energy radiation
82
Q

initiate polymerization by transfer of
an electron to the double bond
of the monomer

A

Alkali metals and alkali metal
complexes

83
Q
A
83
Q
A
84
Q

Initiation by** direct attack **on the
alkali metal involves transfer of
the ____________ from
a Group IA metal atom to the
monomer. A radical ion (i.e., a
species having both ionic and
radical centers) is formed

A

loosely helds electron

85
Q

The radical ion may dimerize to give a dianion

A

Initiation in Anionic Polymerization

86
Q

The initiation process making dianion results in a _____________ capable of propagating at both of its ends

A

bifunctional dicarbanion
species

87
Q

Initiation by organometallic compounds
and Lewis bases occurs by a _____________
of these compounds on the double bond
of the monomer molecule.

A

direct attack

88
Q

Before the Lewis base can attack the
monomer, it must _________, and only then can
a carbanion be formed.

A

ionize

89
Q

Anionic propagation is generally much ________
than free-radical reactions

A

faster

90
Q

Propagation in anionic addition polymerization
results in the __________________ of
monomer.

A

complete consumption

91
Q

If the starting reagents are pure and if the
polymerization reactor is **purged of all oxygen **and traces of water, propagation can

A

proceed indefinitely or until all monomer are consumed.

92
Q

anionic polymerization proceed indefinitely or until all monomer are consumed

A

“living” polymerization.

93
Q

most important group of initiators in Coordination Polymerization

A

Ziegler-Natta catalysts

94
Q

In polymerizations of this type, each monomer is inserted between the growing macromolecule and the initiator.

A

Coordination Polymerization

95
Q

Complexing of the monomer to the initiator frequently precedes the **insertion process **and this polymerization

A

coordination polymerization.

96
Q

The field of coordination polymerization
originated in the __________ with the
pioneering works of ______________________

A

mid-1950s ,

Karl Ziegler in
Germany and Giulio Natta in Italy

97
Q

Karl Ziegler discovered in the early 1950s that a combination of aluminum alkyls with certain ______________________ such as TiCl4 or VCl4
generated complexes that would polymerize
_______________ at low temperatures and pressures,
producing ______________ with an essentially linear
structure, now referred to as ________________________

A

transition metal compounds
ethylene
polyethylene
high-density polyethylene (HDPE)

98
Q

Giulio Natta’s work led to the
recognition that the catalytic complexes described
by Ziegler were capable of polymerizing _____________
(commonly known as ___________ in the chemical
industry) to yield stereoregular polymers.

A

1-alkenes
alpha olefins

99
Q

Many polymers are now manufactured on a commercial scale using Ziegler-Natta catalysts, the most prominent among them being ________________ of high molecular weight.

A

stereoregular (isotactic)
polypropylene

100
Q

Since the Ziegler-Natta catalyst systems appear to
function via formation of a **coordination complex ** between the catalyst, growing chain, and incoming monomer, the process is also referred to as
________________ and the catalysts as __________________

A

coordination addition polymerization
coordination catalysts

101
Q

arises because of order in the
spatial structures of polymer chains.

A

Stereoregularity

101
Q

Ziegler–Natta catalyst systems consist of a mixture of the following two classes of compounds:

A
  1. Compounds (normally halides) of transition elements of **groups IV to VIII **called catalyst ( TiCl3, TiCl4, VCl4, e, ZrCl4)
  2. Compounds (hydrides, alkyls, or aryls) of elements of groups I to IV, called cocatalysts (Al(C2H5)3, Al(i-C4H9)3)
102
Q

Coordination Polymerization ordered spatial structures are determined by two
phenomena.

A
  • During the polymerization step the monomer
    units are** joined together in a regular sequence ** determined by the catalyst used and by the polymerization conditions. Regularity of this type cannot be altered or changed during subsequent physical treatment of the polymer.
  • Subsequently these regularly constructed
    polymer chains spontaneously arrange
    themselves     into helical structures
103
Q

Coordination
Polymerization -
Mechanism 3 types
(image 43)

A

isotactic
syndiotactic
atactic

104
Q

Each polymer molecule __________ in size at a rapid
rate once its growth has been started. When the
macromolecule stops growing it ____________ generally
react with more monomers

A

increases , cannot

105
Q

Growth of polymer molecules is caused by a _____________________

A

kinetic
chain of reactions.

106
Q

Chain-growth polymerization involves the reaction
of _________________ that may be free
radicals, ions, or polymer-catalyst bonds

A

monomers with active centers

107
Q

In ______________ polymerizations the mechanisms
and rates of the reactions that initiate, continue, and terminate polymer growth are _____________

A

chain-growth , different.

108
Q

Chain-growth polymerization is usually
initiated by some _______________ and
the reaction is allowed to proceed under
conditions in which monomers ____________ react
with each other without the intervention of
an active center.

A

external source (energy,
highly reactive compound, or catalyst)

cannot

109
Q

Polymers made by chain-growth reactions
are often ____________ by Carothers’s
definition. The most common polymers
made by these processes have only ____________ in their backbones.

A

addition polymers
carboncarbon links

110
Q

refers to a type of polymerization mechanism in
which bi-functional or multifunctional
monomers react to form first dimers, then
trimers, longer oligomers and eventually
long chain polymers.

A

Step-growth polymerization

111
Q

Many naturally-occurring and some
synthetic polymers are produced by

A

Step-growth polymerization

112
Q

polyesters,
polyamides, polyurethanes, etc.example of

A

Step-growth polymerization

113
Q

its** interlinking capacity**, or the
number of sites it has available for
**bonding with other molecules **under the
specific polymerization conditions.

A

functionality

114
Q

A molecule may be classified as
______________________ depending on whether it
has one, two, or greater than two sites
available for linking with other
molecules.

A

monofunctional, bifunctional, or
polyfunctional

115
Q

In step-growth polymerization, the **stepwise
reaction **occurs between pairs of _____________________ on the reacting
molecules.

A

chemically
reactive or functional groups

116
Q

There is usually a **low-molecular-weight **byproduct such as water that is eliminated (or
condensed)

A

STEP-GROWTH
POLYMERIZATION

117
Q

No reactant species has the chemical formula of the repeat unit, and the intermolecular reaction occurs every time a repeat unit is formed.

A

STEP-GROWTH
POLYMERIZATION

118
Q

Each step may consist of a combination of two
polymers having a different or the same length to form a longer-length molecule.

A

STEP-GROWTH
POLYMERIZATION

119
Q

In a step-growth polymerization, the molecular weight of the polymer chain builds
up ____________ and there is __________reaction mechanism for the formation of polymer

A

slowly , only one

120
Q

The polymerization reaction proceeds by individual reactions of the functional
groups on the monomers.

A

STEP-GROWTH POLYMERIZATION

121
Q

two monomers react to form a dimer

Monomer + Monomer = Dimer +H2O

A

STEP-GROWTH POLYMERIZATION
(1st step)

122
Q

The dimer may now react with another dimer to produce a tetramer, or the dimer
may react with more monomer to form a trimer

Monomer + Dimer = Trimer +H2O
Dimer + Dimer = Tetramer + H2O

A

STEP-GROWTH POLYMERIZATION (2nd step so on)

123
Q

Any two species in the reaction mixture can react with
each other.

A

STEP-GROWTH POLYMERIZATION

124
Q

expressed by n-mer +m-mer = (n+m)-mer

A

Step polymerization
(n and m from 1- large number)

125
Q

reaction between dimethyl terephthalate and ethylene glycol to form a

A

linear poly(ethylene terephthalate) or
PET molecule with methyl alcohol as a by-product

126
Q

Small molecule is eliminated at each step

A

Polycondensation

127
Q

The structural unit in step-growth polymers is __________________ to the structure of the starting
monomer(s).

A

not
identical chemically

128
Q

Step-growth polymers derive their names from
the __________________ involved in the polymerization process.

A

reactive type (characteristic interunit linkage)

129
Q

In the reaction between the glycol and
dicarboxylic acid, the resulting
polymer is a ___________, in consonance with the
general name of reactions between ____________________

A

polyester
hydroxyl groups (–OH) and carboxylic cid groups (–COOH)

130
Q

Monomers react without the elimination of a small molecule.

A

Polyaddition

131
Q

______________ form a large class of
commercially important
polymers.

A

Polyesters

132
Q

A typical polyester
is ______________________ the largest volume
synthetic fiber. It is also used
as ______________ and in bottle
applications.

A

poly(ethylene terephthalate)
(PETP)
film (mylar)

133
Q

s are a special class of polyesters derived from carbonic acid (image 56)

A

Polycarbonates

134
Q

second largest by volume engineering thermoplastics next
to polyamides.

A

Polycarbonates

135
Q

Polycarbonates preparation involves the linking together of _______________ ,
by reacting them with a derivative of carbonic acid such as ____________________________

A

aromatic dihydroxy compounds (2,2-bis(4-hydroxyphenyl) propane or bisphenol A)

phosgene or diphenyl carbonate

136
Q

characterized by the
presence of amide linkages (–CONH–) on the polymer main chain.

A

Polyamides, or nylons

137
Q

a large number of polyamides can be synthesized based on four main synthetic routes

A

(1) condensation reaction between a dicarboxylic acid and a diamine,
(2) reaction between a diacid chloride and a diamine,
(3) dehydration–condensation reactions of amino acids
(4) ring-opening polymerization of
lactams.

138
Q

nylons may be divided into two categories

A

based on synthetic routes (1) and (2)
based on routes (3) and (4).

139
Q

are condensation polymers obtained from the reaction of dianhydrides with diamines.

A

Polyimides

140
Q

synthesized generally from aromatic dianhydrides and** aliphatic diamines**

A

Polyimides

141
Q

from the reaction of aromatic dianhydrides with aromatic diamines.

A

aromatic polyimides

142
Q

families of synthetic heterocycles with a wide
range of applications due to their physical and
chemical properties

A

Polybenzimidazoles and
Polybenzoxazoles

143
Q

These man-made molecules are commonly used in medicinal, agricultural, and environmental areas due to their **ability to form strong metallic complexes **and their unique thermal and electrical
properties.

A

Polybenzimidazoles and
Polybenzoxazoles

144
Q

also known as ladder
polymers or linker polymers

A

Aromatic ladder polymers,

145
Q

type of polymer that consists of repeating units connected by aromatic linkers, such as benzene rings.

A

Aromatic ladder polymers,

146
Q

popular for their **versatility **and
can be used in a variety of applications, including
coatings, adhesives, and membranes.

A

Aromatic Ladder Polymers

147
Q

Ladder polymers are designed to have ____________________ and _____________________,
which makes them resistant to heat and degradation.

A

high
molecular weights and high melting temperatures

148
Q

employed in the production of aminoplasts and phenoplasts, which are two different but related classes of thermoset polymers.

A

Formaldehyde

149
Q

aminoplasts and phenoplasts

A

thermoset polymers

150
Q

are products of the condensation reaction between either urea (urea–formaldehyde or UF resins) or** melamine** (melamine–formaldehyde or MF resins) with formaldehyde.

A

Aminoplasts

151
Q

are prepared from the condensation products of phenol or resorcinol and formaldehyde

A

Phenoplasts or phenolic (phenol–formaldehyde or PF)

152
Q

are polymers consisting of monomers joined together by ether linkages (two carbon atoms bonded to an oxygen atom).

A

Polyethers

153
Q

example of Polyethers

A

elastomers

154
Q

The structures of the Polyethers compounds vary
significantly, yet they all preserve the ____________.

A

C—O—C
connection

155
Q

Polyethers can be either _____________ polyethers.

A

aliphatic or
aromatic

156
Q

closely related to polyethers in
structure and properties

A

Polysulfides

157
Q

Polysulfides also known as

A

Aromatic polythioethers

158
Q

A typical aromatic polysulfide is _____________ which is used as electrical insulators and structural parts in the building of engines and vehicles.

A

poly(phenylene sulfide)
(PPS),

159
Q

is prepared by the condensation
reaction between p-dichlorobenzene and sodium sulfide

A

Poly(phenylene sulfide)

160
Q

Another family of linear aromatic
polymers which are tough, high-temperature-resistant engineering thermoplastics.

A

Polysulfones

161
Q

Polysulfones may be synthesized by
the nucleophilic substitution of ________________ with activated ___________________.

A

alkali salts of biphenates
aromatic dihalides

162
Q

A polysulfone from the reaction of disodium salt of
bisphenol A with dichlorodiphenyl sulfone

A

preparation
of bisphenol

163
Q

In STEP-GROWTH, Monomers bearing _______________________ undergo step
polymerization.

A

functional groups such as
-OH, -COOH, -NH2, -NCO, etc.,

164
Q

```

~~~

In chain growth, Monomers with ____________________
undergo polymerization when an active center
is formed.

A

carbon-carbon unsaturation

165
Q

In step-growth , the growth of polymer molecules proceeds
by a ______________________________ , normally with the elimination of small molecules as by-products of condensation, such as H2O, HCl, NH3, etc., in each step.

A

stepwise intermolecular reaction (at a
relatively slow rate

166
Q

The molecule never stops growing during polymerization.

A

STEP-GROWTH

167
Q

Any two molecular species present can react.

A

STEP-GROWTH

168
Q

In chain growth. each polymer molecule/chain ____________ once its growth has been
started by formation of an active center.

A

increases in size at a rapid rate

169
Q

When the macromolecule stops growing (due to
termination reaction) it can generally not react
with more monomers (barring side reactions)

A

CHAIN-GROWTH

170
Q

Only growth reaction adds repeating unit one
at a time of the chain.

A

CHAIN-GROWTH

171
Q

In STEP-GROWTH, Monomer units _______react with each other or with polymers of any size.

A

can

172
Q

Growth occurs in a _____________ and starts as the reactive species of a monomer or polymer encounters other species with which it can form a link.

A

series of fits

173
Q

This can occur even in the absence of an added catalyst

A

STEP-GROWTH

174
Q

In chain growth of a polymer molecule is caused by
a kinetic chain of reactions involving rapid
addition of monomer to an active center that
may be a _______________________

A

free radical, ion, or polymer-catalyst
bond.

175
Q

The active center is produced by some
external source (energy, highly reactive
compound, or catalyst)

A

CHAIN-GROWTH

176
Q

At any moment the reaction mixture essentially
consists of full-grown,** large polymer molecules,** unreacted monomer molecules, and a very low concentration (10-8- 10-3 mol L-1) of growing chains (i.e., possessing an active center) of intermediate sizes

A

CHAIN-GROWTH

177
Q

In STEP-GROWTH, backbone of polymer chains contains
________________________ at **regular
intervals **due to condensed interunit links.

A

heteroatoms such as N, O, S, etc.,

178
Q

In chain growth, usually the backbone of polymer chains consists
of_____________ and other kinds of
atoms such as O, N, S, etc., may appear in the
side groups

A

-C-C- linkages

179
Q

A polymerization in which a cyclic monomer yields a monomeric unit which is acyclic or contains fewer cycles than the
monomer.

A

RING-OPENING POLYMERIZATION

180
Q

Ring-opening polymerization (ROP) is a form of chain-growth polymerization in which the** terminus of a polymer chain attacks** ___________ to form a longer polymer. The reactive center can
be radical, anionic or cationic.

A

cyclic monomers

181
Q

method where cylic monomers are
opened up to make extended chain
structures.

A

RING-OPENING POLYMERIZATION

182
Q

The RING-OPENING POLYMERIZATION reaction is typically
driven by the release of

A

ring strain

183
Q

example of ringopening of cyclic organic
compounds

A

epoxides
- ethylene
- propylene oxides
- epichlorohydrin

other cyclic ethers
- trioxane
- tetrahydrofuran.

Other important systems include
- cyclic esters (lactones)
- cyclic amides (lactams)
- cycloolefins
- siloxane.

184
Q

Major applications of polymers
obtained from ring-opening
polymerization are in

A

coatings
fibers
elastomers
adhesives
thermoplastics
thermoset-based composite system

185
Q

RING-OPENING
POLYMERIZATION

A
  1. initial ring-opening of the cyclic monomer
  2. polyaddition.
  3. resulting polymers are normally linear.
186
Q

Their structural units usually have the same
composition as the monomer.

A

RING-OPENING
POLYMERIZATION

187
Q

(image 73)

  1. type
  2. what is the X?
A

RING-OPENING
POLYMERIZATION

X may be a heteroatom such as O, S,
or a group like NH, –O–CO–, –NH–CO, or –C›
C–.

188
Q

________________ is capable of ring-opening
polymerization to produce a linear chain of
degree of polymerization, n.

A

Cyclic structure

189
Q

such that it** provides a mechanism** for a
catalyst or initiator to form the initiating
coordination intermediate with the cyclic
ring.

A

nature of X

Q1 Pollyyyy (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions