Which of the following is (are)repeating unit(s)of step-growth polymers?

Question

Quizplus · Accepted Answer

The repeating units of step-growth polymers are formed through the reaction of two or more different monomers, resulting in a polymer chain that grows step-by-step. Choice I represents a repeating unit in polyesters, which are a type of step-growth polymer formed from the reaction of a diol and a dicarboxylic acid. Choice II represents a repeating unit in polyurethanes, which are another example of a step-growth polymer formed from the reaction of a diisocyanate and a diol. Choice III represents a repeating unit in polyethylene, which is a type of addition polymer formed by the repeated addition of ethylene monomers. Therefore, only choices I and II are examples of repeating units in step-growth polymers, making the correct answer choice D.

Which of the Following Is (Are)repeating Unit(s)of Step-Growth Polymers