שאלה | Which of the following statements on polymerization mechanisms is correct? (Choose from the following four possibilities)

Which of the following statements on polymerization mechanisms is correct? (Choose from the following four possibilities)

		In chain reaction polymerization by peroxide or azo initiators the termination step can be easily controlled to achieve a narrow molecular weight range
		Step polymerization reactions such as the reaction of di-isocyanates with di-alcohols always have a reaction by-product in the polymerization reaction
		In step condensation and step addition polymerization as close as possible to exact Vstoichiometry of reactive groups is needed for achieving high molecular weight.
		None of the above