In the process of condensation polymerization, how does an increase in the degree of polymerization typically affect the mechanical strength of the resulting polymer?

When a condensation polymerization produces longer chains, the polymer has more covalent bonds linking the monomer units, so the material can spread stress over a larger volume and resist deformation better. Each additional repeat unit adds to the overall stiffness and toughness because the load is shared among more links, reducing the chance of a single bond breaking. In practice, a polymer with a degree of polymerization of several thousand often shows higher tensile strength and modulus than one with only a few hundred units. For example, polyamide 6,6 made from 1,6-hexanediol and adipic acid forms chains with thousands of units and exhibits a tensile strength of about 70 MPa, whereas a short‑chain version with a degree of polymerization around 50 only reaches about 20 MPa. Thus, increasing the degree of polymerization generally improves the mechanical strength of the resulting polymer.