Chain-growth products: chain-growth (addition) polymerisation adds monomers to active chain ends and requires initiators. Which of the following is a product of chain-growth polymerisation?

Introduction / Context:
Polymerisation route dictates molecular weight build-up and typical structures. Chain-growth (addition) polymerisation proceeds via radicals, ions, or coordination sites adding unsaturated monomers. Recognising which commercial polymers arise from addition vs. condensation pathways is a frequent test of fundamentals.

Given Data / Assumptions:

• Vinyl monomers (like tetrafluoroethylene) form addition polymers.
• Condensation polymers (nylons, PET, Bakelite) form via step-growth with small-molecule elimination or ring opening.

Concept / Approach:
PTFE (Teflon) forms by chain-growth addition of tetrafluoroethylene. Nylon-66 and PET are condensation polymers (step-growth) formed from bifunctional monomers eliminating water or methanol; Bakelite is a step-growth phenol–formaldehyde network. Therefore, among the options, PTFE is the clear example of a chain-growth product.

Step-by-Step Solution:

Verification / Alternative check:
Mechanistic overviews in polymer texts place vinyl polymers (PE, PP, PVC, PTFE, PS) in the chain-growth category.

Why Other Options Are Wrong:

• Nylon-66/PET/Bakelite/polycarbonate: canonical step-growth systems.

Common Pitfalls:
Misclassifying ring-opening (e.g., caprolactam to nylon-6) as chain-growth; although it proceeds by chains, it is a step-growth condensation process at the functional group level.

Final Answer:
Teflon (PTFE)