Question

Which of the following is not a semi synthetic polymer?
A. Cis-Polyisoprene
B. Cellulose nitrate
C. Cellulose acetate
D. Vulcanized rubber

Answer 1

Hint: Polymers that are not natural can be synthesized in a lot of ways. Each pathway provides and generates polymers of different nature and thus they are characterised.

Complete step by step answer:
-Polymers may be divided into two categories based on their origin:
Natural polymers and Synthetic polymers.
-As the name suggests natural polymers are the complex compounds of high molecular mass obtained from natural sources. For example starch, cellulose, proteins etc.
-Again Synthetic polymers are man made commercial polymer products which have specified properties e.g., synthetic rubber can be made to have such properties that cant be achieved with natural rubber. They can be designed to withstand very high temperatures. Some examples are PVC, Teflon, nylon, Bakelite etc.

-On the other hand semi-synthetic polymers are the polymers made by modification of the properties of the natural polymers. Some important examples are nitrocellulose, cellulose acetate etc. Gun cotton is actually cellulose nitrate and it is mainly used in making explosives. Again cellulose acetate can be obtained from cellulose by acetylating cellulose which is used in making films, threads. Vulcanised rubber, made by heating natural rubber with sulphur, has a lot of improved properties and used in making tyres. Therefore Cellulose nitrate, cellulose acetate and vulcanised rubber are examples of semi synthetic polymers.
-Cis-Polyisoprene is an nothing but natural rubber as isoprene is the main compound of forming natural rubber. So, the correct answer is “Option A”.

Note: The vulcanised rubber has a lot more advantages over natural rubber. It has high elasticity, tensile strength and even high thermal stability. To provide these characteristics the natural rubber is modified to produce the vulcanised rubber which is a semi synthetic polymer.