A Design of Experiments Approach to Analyze the Effects of Hydroxyapatite and Maleic Anhydride Grafted Polyethylene Contents on Mechanical, Thermal and Biocompatibility Properties of Green High-Density Polyethylene-Based Composites

Composites based on green high-density polyethylene (G-HDPE) and hydroxyapatite (HA) compatibilized with maleic anhydride grafted high-density polyethylene (HDPE-g-MAH) were developed in this work. The main objective was to evaluate the effects of HA and HDPE-g-MAH contents on the mechanical and thermal properties and hydrolytic degradation of composites through design of experiments and statistical analysis, as well as to evaluate the hemolytic stability. Hydroxyapatite acts as a reinforcing agent for the G-HDPE matrix while the HDPE-g-MAH acts as a compatibilizing agent, improving the dispersion of the HA particles in the polymer matrix and thus increasing the mechanical properties. The crystallization temperature and the degree of crystallinity of the polymer matrix were increased with the addition of HA, suggesting the filler acts as a heterogeneous nucleating agent. Hemolysis tests performed on a composite sample with best mechanical performance did not indicate significant hydrolytic degradation, which suggests this composite is a promising material to be used in bone tissue engineering, for application in implants and bone grafts.

Keywords:
Green Polymers; Green Polyethylene; Hydroxyapatite; Green Polymer Hydroxyapatite Composites; Green HDPE and hydroxyapatite composites; HDPE-g-MAH; Design of experiments