The Effect of Surface Treatment on Properties of Polylactic Acid/β-Tricalcium Phosphate Composite Materials

The effects of surface modification on the mechanical properties of polylactic acid/beta-tricalcium phosphate (PLLA/beta-TCP) composite materials, as well as the weight loss (WL) and water absorption (WA) of the composites during degradation process were systematically investigated in this work. PLLA/beta-TCP composites with four different concentrations of beta-TCP were prepared by hot-pressing. The results showed that tensile modulus of the composites increased with increasing the content of beta-TCP, whereas the tensile strength and bending strength decreased. However, when beta-TCP powders were surface treated (beta-TCPt) by oleic acid, the tensile modulus of 20% beta-TCPt/PLLA were increased by 5.3% further, compared with PLLA/20% beta-TCP. Meanwhile, the tensile strength and bending strength of 20% beta-TCPt/PLLA also increased by 12.64% and 25.97%, respectively. With the time of degradation increasing, both WL and WA of PLLA/beta-TCP and PLLA/beta-TCPt were increased. After degradation for 8 weeks, the WL and WA of PLLA/beta-TCP were higher than those of PLLA/beta-TCPt by 0.05% and 0.22%, respectively, indicating the interface bonding between PLLA and surface treated beta-TCP was stronger than the bonding between PLLA and untreated beta-TCP.