Physical and Impact Behavior of HDPE Composites Reinforced With Woven Ramie and Hydroxyapatite

Abstrak

This study investigates the physical and impact behavior of high-density polyethylene (HDPE) composites reinforced with woven ramie fiber and hydroxyapatite (HAp) filler derived from bovine bone waste. The composites were fabricated by mixing ground HDPE, alkali-treated woven ramie fibers, and HAp powder at varying filler volume fractions (0%, 2%, 4%, 6%, and 8%), while maintaining a constant fiber fraction. The mixture was hot-pressed in an aluminum mold at 250°C for one hour to produce test specimens. Impact strength was evaluated according to ISO 179-2, and density was measured following ASTM D792. Macroscopic and microscopic analyses of fracture surfaces were conducted to assess failure mechanisms. The results show that the addition of 2% HAp led to a substantial increase in impact strength, with a 48.7% improvement compared to the unfilled composite. A marginal increase was observed at 4% HAp, while further increases to 6% and 8% resulted in significant decreases in impact strength, by 23.2% and 12.6% respectively, due to particle agglomeration and increased brittleness. Density measurements revealed a consistent increase with higher HAp content, reflecting the higher intrinsic density of the filler. However, the relationship between density and impact strength was not linear, as excessive filler content led to embrittlement despite higher density. Macroscopic and microscopic observations confirmed a transition from ductile to brittle fracture modes as HAp content increased, with optimal energy absorption and fiber-matrix bonding observed at lower filler fractions. These findings highlight the importance of optimizing HAp content to achieve the best balance between mechanical performance and material density. The study demonstrates the potential of utilizing local waste resources for the development of sustainable, high-performance biocomposites suitable for engineering and biomedical applications.

Kata kunci

• Density
• HDPE
• Hydroxyapatite
• Impact
• Ramie