Synthesis and characterization of engineered PEEK‐based composites for enhanced tribological and mechanical performance

Abstract

AbstractWe report the synthesis and characterization of engineered PEEK‐based composites by using biochar (DDGS500—pyrolyzed Distiller's dried grains with soluble (DDGS)), metal (Mo), and PEEK‐ceramic (Xonotlite) as reinforcements. A systematic study was done to understand the effect of these additives on functional and mechanical properties. Initially, these composites were synthesized by hot pressing. Microstructure analysis of reinforcement powders by scanning electron microscopy (SEM). Detailed microstructure study of the composites showed that DDGS500 powder particulates were well dispersed within the PEEK matrix after the addition of 5 vol%. However, at higher concentration of 10 and 20 vol%, the particles segregated at the phase boundaries and PEEK rich cores were observed in the microstructure. Mo and Xonotlite particles were segregated at the phase boundaries even at 5 vol% concentration, which was more prominent at higher concentrations of 10 and 20 vol% reinforcements. Differential scanning calorimetry (DSC) showed lowering in melting point (Tm) and crystallization temperature (Tc) and increase in crystallization in all the composites. The addition of DDGS500 and Mo enhanced the plasticity and Ultimate Compressive Strength (UCS) (5 vol% additions of DDGS500 and Mo enhanced the UCS by 12.6% and 32.2%, respectively) of the composites whereas Xonotlite additions increased brittleness of the composites. The addition of DDGS500, PEEK‐Mo, and PEEK‐Xonotlite particulates lowered the wear rate until 10 vol% by several orders of magnitude and stabilized the friction coefficient (μ) versus distance profile. However, significant increase in wear rate at 20 vol% of Xonotlite was observed due to third body abrasion. All the composites showed hydrophobic behavior except PEEK‐20 vol% Xonotlite, which showed hydrophilic behavior with a decrease in contact angle as a function of time, which shows that Xonotlite can be a promising additive for increasing hydrophilicity of PEEK‐based composites for biomedical applications.