Polymers Flashcards
Branch chain polymer eg
amylopectin, glycogen, low density polyethylene and all
vulcanised rubbers.
Condition for condensation polymerization
For condensation polymerisation, monomers should have at least two functional groups.
What is zieglar natta catalyst and what kind of polymers does it give and what kind of polyethelene is formed high/low density
Ziegler-
Natta catalyst [(C2H5)3 Al] and TiCl4
zieglar catalysts give linear, stereoregular polymers
High density polyethylene is prepared using a Ziegler-Natta catalyst.
What are elastomers, what kinda forces is present in it, and what are the eg
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.
How are individual chains in fibres held together
Fibres are linear polymers in which the individual chains of a polymer are held together by hydrogen bonds and / or dipole-dipole attraction.
Fibres have _____ tensile strength,_____ MP, _____ solubility, ____ elasticity
and reason ?
high tensile strength, high melting point, low solubility, least elasticity
reason- strong intermolecular forces of attraction and highly ordered strucutre
Eg of fibres
Examples are cellulose, nylon, terylene, wool, silk etc.
Thermo plastic eg
polyethene polypropylene, polystyrene,
polyvinyl chloride. teflon etc.
what is thermosetting polymers?
Polymers which become hard on heating are called thermosetting
polymers.
What kinda polymers are cross linked polymers
Thermosetting polymers are cross- linked polymers.
Eg of thermo setting polymers
Examples are : phenol formaldehyde resin, urea-formaldehyde resin,
melamine - formaldehyde resin.
Natural rubber str, name,common name in normal and polymer form
Natural rubber is a polymer of 2-methyl-1.3-butadiene
common name- isoprene or cis-polyisoprene in polymer form
the difference between gutta purcha and the cis-polyisoprene.
gutta purcha and cis poly isoprene have same structure but just the gutta purcha is trans and cis polyisoprene is cis
Gutta purcha str
wrong
its trans poly isoprene
gutta percha is harder/softer and more flexible/brittle
harder and brittle
Gutta purcha use
It is the filling material that
dentists use in root canal treatment.
Why are rubber vulcanized?!
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
how are rubber vulcanised
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.
What are synthetic rubber
Polymers of 1,3 - butadienes are called synthetic rubbers
forms ____ after polymerization
Whats the polymer called if G=Cl in
neoprene
how is the conversion of chloroprene to neoprene carried out!? (catalyst?)
zieglar natta catalyst
Where are neoprene used and what are they resistant to
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.
Buna S also called ___ and its full form and what is it made of
SBR:- styrene butadiene rubber
Buna-S rubber is a copolymer of three moles of butadiene and one mole of
styrene.
Styrene structure
structure buna-S
Buna S is resistant/not resistant to wear and tear
It is extremely resistant to wear and tear
what does Buna S needs to start its formation reactioN!? and also give the reaction
Nascent Oxygen
use of Buna-S
used in the manufacture of tyres and other mechanical rubber goods.
Buna N is formed by
It is obtained by co-polymerisation of butadiene and
acrylonitrile
Acrylonitrile str
structure of Buna-N
C=C-CN
1,3 buta diene
Where is buna N mostly used in
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.
Nylon is used for what
Nylon is used for all synthetic fibres forming polyamides, i.e.,having a
protein like structure.
Nylon x y what does x,y represents
x determines the number of C atoms in amine
y determines the number of C atoms in acid
Nylon 66 is obtained by hydrogenation/condensation
condensation
Nylon 66 str and is made by
Nylon 6 str and what it ismade of
made by caprolactum
Low density polyethylene is manufactured by and what kind of polymerisation does it has?!
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.
are low density polyethylene branches structure or linear?
branched
why do low density polythenlene have less densityq
because they have branched strucutre
use of low density polyethelyne
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.
High density polyethylene is prepared by
It is prepared by the use of Ziegler - Natta catalyst at high temperature but at low pressure
what kind of structure does high denisty polythelene has? branched or linear
linear
use of high-density polyethylene
It is used in the manufacture of containers ( buckets, tubes), housewares, bottles, and toys.
Melamine polymer is also known as and melamine polymer srtr
Melamine - formaldehyde resin
Bakelite is also known as and how is it formed
Phenol-formaldehyde resins
obtained by the reaction of phenol and formaldehyde in the presence of either an acid or a basic catalyst.
novolac and bakelite structure
Dacron is polyethylene/polyester
polyester
Dacron str
Eg of biodegradable polymers
PHBV:- Poly- hydroxybutyrate-CO-β-Hydroxyvalerate
NYLON-2-NYLON-6
Teflon’s monomer
tetrafluoroethylene
PVC’s monomer
vinyl chloride
Vinyl cyanide is also called as and monomer of
poly acrylonitrile or orlon
Buna N is a organic or synthetic polymer!?
synthetic
which polymer is fully flourinated?
teflon
eg of semi-synthetic polymers
cellulose acetate and cellulose nitrate
what kind of monomers are used in addition polymerization or chain growth polymerization
unsaturated compounds
eg of free radical generating initiator
benzoyl peroxide
acetyl peroxide
tert butyl peroxide
What Does the process of ethene to polythene consists of?
it consists of heating or exposing to light a mixture of ethene with a small amount of benzoyl peroxide initiator
how is teflon formed?
teflon is manufactured by heating tetrafluoroethylene with a free radical or persulphate catalyst at high pressures
where are teflon used?
its used in making oil seals and gaskets and also used for non-stick surface coated utensils
what can be a substitute for wool?
Polyacrylonitrile is used as a substitute for wool in making commercial fibres as orlon or acrilan
how are polyacrylonitrile formed
condensation polymerization requires
a bifunctional or trifunctional monomeric units
how is dacron formed?
formation of terylene and Dacron is an eg of which kind of polymerisation
condensation polymerization
why does nylon has high tensile strength
hydrogen bonding
why does nylon have crystalline nature
intermolecular forces like hydrogen bonding. These strong forces also lead to close packing of chains and thus impart crystalline nature.
how is nylon 6 oobtained?
heating copralactum with water at high temperature
polyesters are
These are the polycondensation products of dicarboxylic acids and diols
eg of polyesters are
Dacron or terylene is the best-known example of polyesters
whats a initiator/catalyst in dacron formation?
zinc acetate-antimony trioxide
melamine formaldehyde polymer formation
Copolymers have properties quite different from homopolymers
true or false
trure
what can be good substitute for natural rubber? and why
butadiene - styrene copolymer is quite tough and is
a good substitute for natural rubber
why does natural rubber stretch?
the polymer chains are held together by the weak intermolecular forces. These weak binding forces permit the polymer to be stretched
what allows rubber to retract to its position
A few ‘crosslinks’ are introduced in between the chains, which help the polymer to retract to its original position after the force is released.
rubber latex cause which type of solution?
colloidal dispersion
how are buna N formed?
Buna–N is obtained by the copolymerisation of 1, 3 – buta–1, 3–diene and acrylonitrile in the presence of a peroxide catalyst
how are PHBV formed?
