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.
