Polymers Test -...

Terylene (Dacron) is the polyester of

GRA is a copolymer of __________________.

Free radical polymerisation requires a free radical initiator. The most commonly used free radical initiator is:

Saran is a copolymer of ___________.

If $$N_1,\ N_2, \ N_3,....$$ are the number of molecules with molecular masses $$M_1,\ M_2,\ M_3, ...$$ respectively, then mass average molar mass is expressed as :

Molecular weights of macromolecules are determined by :

Identify $$X$$ in the reaction.

Average molecular mass of a polymer is determined by:

The PDI (polydisersity index) is the ratio of weight to number-average molecular masses, $$M \bar{w} / M \bar{n}$$. In natural polymers, which are generally monodispersed, PDI is ............. and in synthetic polymers which are always polydispersed, PDI is ............. because $$M \bar {w}$$ is always ............. than $$M \bar {n}$$. Fill in the blanks. 

A polymeric sample in which $$30\%$$ molecules have a molecular mass $$20,000$$, $$40\%$$ have $$30,000$$ and the rest $$30\%$$ have $$60,000$$. The $$( \bar{M}_{n})$$ and $$( \bar{M}_{w})$$ of this sample are, respectively: