5 Explain why increasing crosslinking or degree of crystalli

(5) Explain why increasing crosslinking or degree of crystallinity of a polymer will enhance its resistance to swelling and dissolution.

Solution

During the process of swelling and dissolution of polymers, the molecules of the solute tend to diffuse and occupy positions among the macro molecules of the polymers. This will force the polymer macro molecules to move apart from each other. By increasing the degree of crystallinity and cross-linking of polymers, the resistance to swelling and dissolution is greatly enhanced since there will be a high degree of intermolecular bonding between the adjacent chains in the polymer substances due to increasing degree of crystallinity and cross-linking and this in turn restricts the number of molecules of the solute which can fit into the positions in the adjacent chains of the polymer substances