Engineered Porosity in Microcrystalline Diamond-Reinforced PLLA Composites: Effects of Particle Concentration on Thermal and Structural Properties

TL;DR

This study creates biodegradable composites with diamond particles to control porosity for use in tissue engineering and thermal management.

Contribution

The novel use of microcrystalline diamond particles to engineer hierarchical porosity in biodegradable composites is introduced.

Findings

Diamond-polymer composites with porosity ranging from 11.4% to 32.8% were successfully created.

Smaller diamond particles reduced porosity from 27.3% at 5 wt% to 11.4% at 75 wt%.

Thermal analysis showed decreased melting temperatures with higher diamond content.

Abstract

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.

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