Abstract
This study aimed to evaluate the effect of the surface modification ratio (the area fraction of the HAp surface modified by the modification polymers) on the hydrolysis properties of HAp/PLA composites. Here, the negatively charged sodium alginate and positively charged chitosan were adsorbed to the positive and negative charge of the HAps, respectively. The surface modification ratio was adjusted to 100 [%], 75 [%], and 50 [%] for the preparation of the hybrid-interface-controlled HAp/PLA. The hybrid-interface-controlled HAp/PLA specimens were hydrolyzed by immersing into the simulated in-vivo conditions for 0, 1, 2, and 4[weeks], and were then subjected to tensile tests. In the case of hybrid-interface-controlled HAp/PLA with the sodium alginate and the chitosan, the tensile strength increased with increasing the surface modification ratio. The decrease in tensile strength due to hydrolysis was the most suppressed under the condition where the surface modification ratio was 100 [%]. This suggests that the optimal design of the molecular structure for the hybrid-interface-control using the sodium alginate and the chitosan could be achieved at a surface modification ratio of 100[%].
