Question

How do polyesters such as PLA and PGA degrade? What are some properties that affect their rate of degradation? Explain how autocatalysis can influence their degradation

Answer 1

Polyesters such as PLA and PGA degrade in presence of acidic catalyst. It causes degradation mainly at high temperature and high pressure during processing.

Properties affecting rate of degradation are tensile strength, molecular weight , solubility , effect of composition, effect of crystallinity e.t.c

In autocatalysis the hydrolysis reaction is catalysed by carboxylic acid chain ends of water soluble oligomers and monomers. In this type it is observed that hydrolysis occurs largely faster at core of large samples compared to surface beacause oligomers and monomers, which act as catalyst diffuse out of polymer near surface.