Question

1.) Which type of polymerization starts when a free radical is mixed with monomer units?

	1) Sequential polymerization
	2) Addition polymerization
	3) Subtraction polymerization
	4) Condensation polymerization

2.) Which of the following are structural features of a weak polymer? (choose all that apply)

	small substituent side-chain groups
	large substituent side-chain groups
	lots of branching in the backbone
	little branching in the backbone

Answer 1

1) When a free radical is mixed with monomer units then the radical adds up to the monomer and forms a chain of monomers that is polymer. Thus the answer is ADDITION POLYMERISATION. Here the free radical is just added, hence it is not substraction polymerisation. Morover it is not condensation polymer as no water molecule is released.

2) Branching will increase the strength of the polymer hence that cannot be the answer. So little branching is one of the answer. When we compare the substituents, large substituents can cause steric hinderance and thus weaken the polymer. Therefore the answers are Large substituent side chain groups and little branching