Chemical Engineering - Polymer Technology - Discussion

How, can anyone explain this?

PVC is heat sensitive material. When it is reached up to its melting temperature the thermal dehydrochlorination of PVC begins where 99 wt % of Cl in PVC released as HCl.

The main disadvantage of PVC is the limited thermal stability. When PVC reaches its melting point in between 140-160 degree celsius, gives the elimination of hydrogen chloride at relatively low temperature (about 100-degree celsius) which is smaller than PVC melting point gives the rise in PVC decomposition.

During decomposition dehydrochlorination (formation of polyene structure observed). PVC can be degraded by three main mechanisms, i) Dehydrochlorination, ii) Oxidation, iii) Loss of plastisizer.

Thermosetting polymers such as Bakelite have the tendency of decomposing before melting. Thermoplastic polymers (such as PVC (polyvinyl chloride), and polystyrene) on heating, becomes soft and on cooling, become hard. They can be remoulded and recycled. Their properties are between elastomers and fibres.

There is no thermosetting given in the option, all are thermoplastic.

Hence, the correct option is D.

Yes, Right @KRR.

As no options are from thermosetting, so the right option will be D.