Engineered Porosity in Microcrystalline Diamond-Reinforced PLLA Composites: Effects of Particle Concentration on...

This research explores microcrystalline diamond particles in poly(L-lactic acid) matrices to create structured porous composites for advanced biodegradable materials. While nanodiamond-polymer composites are well-documented, microcrystalline diamond particles remain unexplored for controlling hierarchical porosity in systems required by tissue engineering, thermal management, and filtration industries. We investigate diamond-polymer composites with concentrations from 5 to 75 wt% using freeze-drying methodology, employing two particle sizes: 0.125 μm and 1.00 μm diameter particles. Systematic porosity control ranges from 11.4% to 32.8%, with smaller particles demonstrating reduction from 27.3% at 5 wt% to 11.4% at 75 wt% loading. Characterization through infrared spectroscopy, X-ray computed microtomography, and Raman analysis confirms purely physical diamond-polymer interactions without chemical bonding, validated by characteristic diamond lattice vibrations at 1332 cm^-1. Thermal analysis reveals modified crystallization behavior with decreased melting temperatures from 180 to 181 °C to 172 °C. The investigation demonstrates a controllable transition from large-volume interconnected pores to numerous small-volume closed pores with increasing diamond content. These composites provide a quantitative framework for designing hierarchical structures applicable to tissue engineering scaffolds, thermal management systems, and specialized filtration technologies requiring biodegradable materials with engineered porosity and enhanced thermal conductivity.