Polycondensation (step-growth) polymerisation: which statement correctly describes a material or outcome commonly produced by this mechanism?

Introduction / Context:
Polymerisation mechanisms are broadly divided into step-growth (polycondensation) and chain-growth (addition). Understanding which polymers derive from which mechanism is fundamental for predicting properties, processing routes, and cure behaviour. This item asks for a true statement about polycondensation outcomes.

Given Data / Assumptions:

• Epoxy resins (e.g., based on bisphenol-A and epichlorohydrin) are produced via step-growth reactions, often with small-molecule byproducts in intermediate steps.
• Step-growth can form linear or network (crosslinked) structures depending on monomer functionality (difunctional vs. multifunctional).
• Catalysts or initiators may or may not be required, depending on the specific system.

Concept / Approach:
In step-growth polymerisation, any two molecular species can react at any time, and high molecular weight emerges only at very high conversion. Epoxy systems are classic step-growth thermosets because multifunctional epoxide and hardener molecules react to build a network during cure. Conversely, claims that step-growth cannot make linear polymers or makes only thermoplastics are false; polyesters and polyamides (linear thermoplastics) are produced by step-growth when difunctional monomers are used.

Step-by-Step Solution:
List polymers known from step-growth: polyesters, polyamides, phenolics, epoxies.Identify which options align with this list.Select the statement that matches—epoxy polymers are produced by polycondensation (step-growth).

Verification / Alternative check:
Textbook reaction schemes for epoxy resin production and cure show stepwise glycidyl ether formation and subsequent network formation with hardeners (amines, anhydrides).

Why Other Options Are Wrong:
“Does not produce linear polymers”: wrong; linear PET and nylons are step-growth.“Produces only thermoplastic”: wrong; many step-growth systems are thermosets.“Never requires catalyst”: incorrect generalization; catalysts are common in condensations.“Always monodisperse”: step-growth typically gives broad distributions unless carefully engineered.

Common Pitfalls:
Equating “condensation” exclusively with loss of small molecules; some step-growth systems proceed without byproduct.

Final Answer:
It produces epoxy polymers (epoxy resins).