What occurs during polymerization?

During polymerization, molecules of resin cross-link, which is the process of chemically bonding individual resin molecules to create a larger, more complex molecular structure. This cross-linking involves the formation of covalent bonds between the resin molecules, leading to an interconnected network that significantly enhances the material's properties, such as strength, durability, and thermal resistance.

This transformation is critical in the development of thermosetting plastics, which cannot be remolded after curing due to the stable structure formed during polymerization. This process is fundamental in various applications, particularly in the production of composites, where strength and integrity are vital for performance in demanding environments.

In contrast, options that mention degradation, evaporation, or separation do not accurately reflect the intended outcomes of polymerization. During this process, the goal is to create a robust material rather than to break it down or allow it to evaporate.