Concept:Free-radical addition polymerization requires an initiator (e.g., organic peroxides or azo compounds) that cleaves homolytically under heat to form reactive radical species.
Formula / Reaction:$$\text{Initiation: } \text{R}-\text{O}-\text{O}-\text{R} \xrightarrow{\Delta} 2\,\text{R}-\text{O}^\bullet$$
$$\text{R}-\text{O}^\bullet + \text{CH}_2=\text{CH(Cl)} \longrightarrow \text{R}-\text{O}-\text{CH}_2-\text{C}^\bullet\text{H(Cl)}$$
Solution:- The generated radical attacks the \(\pi\)-bond of vinyl chloride monomer, creating a carbon-centered radical that propagates chain growth.
Why other options are incorrect:- Option A: Suspension agents (e.g., polyvinyl alcohol), not initiators, manage suspension stability.
- Option C: PVC is a linear thermoplastic; initiators do not induce cross-linking under standard conditions.
- Option D: \(\text{HCl}\) elimination is an undesirable degradation reaction, not a function of the initiator.
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