The influence of bioactive additives on polylactide accelerated degradation

Abstract

The aim of the research was to study the influence of the bioactive modifiers such as 7 wt.% of micrometric tricalcium phosphate (TCP) and 0.3 wt.% of nanometric hydroxyapatite (HAP) on the accelerated degradation process of composite resorbable implants based on poly(L-lactide) (PLA) matrix. The degradation was assessed on the basis of microstructural, structural and mechanical alterations. The measure of the PLA degradation progress was the gradual decrease in its molecular weight and mechanical strength. As the degradation proceeded, the plastic properties of materials decreased. In the case of composites such changes took place faster, which implies the accelerating influence of modifiers on the degradation process. Moreover, modifiers act as crystallization seeds, accelerating and stimulating the matrix organization and appearance of crystalline areas. The properties of the two composites differ. Adding TCP alone influenced the structural changes in the polymer more significantly than the addition of TCP/HAP, thus affecting the faster degradation.