Network polymer is formed by what?

• A. Multifunctional monomers forming three-dimensional networks
• B. Linear chains with no branching
• C. Branched polymers with limited cross-links
• D. Cross-linked polymers without network formation

Answer: (A)

A network polymer forms when multifunctional monomers—those with more than two reactive sites—link together in multiple directions to build a continuous three-dimensional cross‑linked structure. As these reactive sites connect, the polymer chains become interlinked into a single network that spans the material, often making it insoluble and rigid. If you start from linear chains, there are only two ends and no cross-links to connect the chains into a 3D network, so you don’t get a true network polymer. Branched polymers with only a few cross-links can become large, but they don’t percolate into an infinite 3D network throughout the material, so they behave more like non-network polymers. Cross-linked polymers that don’t form a full network similarly fail to percolate everywhere; they may have isolated cross-links but not a complete, interconnected structure. Thus, the formation of a three-dimensional network is driven by multifunctional monomers creating extensive cross-links.