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Polymers

One Word Answers

41.

Give the chemical name of teflon.

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Short Answer Type

42.

Write the name and structure of one of the common initiators used in free radical addition polymerization.

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43.
Discuss the main purpose of vulcanization of rubber.

Natural rubber becomes soft at high temperature (> 335K) and brittle at low temperatures.(<283K). To improve physical properties of rubber, vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373K to 415K. On vuclcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.