擬似生体環境下でのポリ乳酸の分解の評価

抄録

Bioabsorbable polymer degrades in the body. Degradation rate of bioabsorbable polymer changes with molecular weight, crystallinity and size. In this study, the degradation of bioabsorbable poly(lactic acid) (PLA) was investigated. PLA is molded into plate shape by hot compression method. Molding temperature was 200°C. The plate was cut into tensile test specimen. Annealing was conducted on the specimen. Annealing temperature was 70°C and 130°C. Three types of specimens were used; non-annealing , 70°C-annealing , 130°C-annealing. Immersion test was conducted to evaluate the change in weight-averaged molecular weight due to hydrolysis and tensile test was conducted to clarify the effect of hydrolysis on mechanical properties. Molecular weight of Ingeo 4.5 mm , Ingeo 1.3 mm and Ecodear 1.3 mm of 130°C-annealed did not change at 8 weeks immersion. Young’s modulus of Ingeo 1.3 mm of 130°C-annealed decreased at 8 weeks immersion. Fracture strength of Ecodear 1.3 mm decreased at 8 weeks immersion.