Rubber

Natural Rubber is .......type of polymer.

• Polyamide • Polyester • Polyene• Polyether

Nature rubber is obtained form the tree named

• Hevea brazilensis• Hevea crailensis• Heated brazilensis• None of these

Rubber is kept in smokehouse for 3days at50°C to

• Increases tensile strength• Increases impact strength• Increases resilience• Increases resistance to attack by micro

organism

A Synthetic rubber P Cis-1,4polyisoprene

B Natural rubber Q Trans-1,4polyisoprene

C Gutta-percha R Sulphur crosslinked rubber

d Vulcanized rubber s Styrene –butadiene rubber

a a)-r, b)-p,c)-q ,d)-s

b a)-s, b)-p, c)-r,d)-q

c a)-s, b)-p, c)-q,d)-r

d a)-p,b)-s, c)-q,d)-r

For application like making of tyres,conveyer belts,insulation---- is used

• Natural rubber• Vulcanised rubber• Styrene butadiene rubber• None of these

SBR is an example of

• Copolymer• Condensation polymer• Thermosetting polymer• Branched polymer

Styrene butadiene rubberis prepared by co-polymerisation of

• 90%butadiene+10%styrene by weight• 75%butadiene+25%styrene by weight• 25%butadiene+7510%styrene by weight• 10%butadiene+90%styrene by weight

Styrene and butadiene monomerson polymerization form

• Homopolymer• Copolymer• Croslinked polymer• Inorganic polymer

Mastication of rubber polymer chains is carried out on

• Rollers that are hollow to circulate polymer chains

• Rollers that are hollow to circulate hot and cold water

• Rollers that are hollow to circulate heat generated

• Rollers that are rigid heavy to apply pressure