Aliphatic polyesters. I. The degradation of poly(ϵ‐caprolactone) <i>in vivo</i>

Abstract

Abstract The degradation of poly(ϵ‐caprolactone) in rabbits, rats, and water was studied by measurement of changes in intrinsic viscosity, molecular weight, crystallinity, Young's modulus, and weight. Degradation proceeds by nonenzymatic random hydrolytic cleavage of ester linkages. The process is autocatalytic, and the kinetic relationship M n / M n o = exp(– kt ) is observed until the M n has decreased to approximately 5000. Significant weight loss is not observed until this point but, once initiated, the rate of weight loss depends markedly on the particle size. Chain scission is associated with an increase in crystallinity, which partly determines the rate of degradation.