Study on methods to improve the mechanical properties of aramid/epoxy composites

Polymer composites, in particular aramid-epoxy composites, are widely used in fields such as aerospace, transportation, electronics, etc. due to their excellent mechanical and dielectric properties. This article presents studies of modification and combined reinforcement on the mechanical properties of aramid-epoxy composites. The influence of matrix (epoxy resin) and reinforcing filler (aramid fabric) mass ratio and ways to increase strength characteristics and impact toughness of the composite were studied. Comparative results for composites made by vacuum forming and vacuum infusion methods are presented. Mass ratio of reinforcing filler and matrix varied in the range of 50:50%, 60:40%, 65:35%, and 75:25%. It was found that modifying epoxy resin with polyurethane rubber plasticizer, together with combined reinforcement of aramid fabric/aramid roving, resulted in composite strength up to 720 MPa and impact toughness of 426 kJ/m2. Modification of epoxy resin with tricresyl phosphate leads to composite strength up to 710 MPa and impact toughness of 475 kJ/m2. Thus, it is shown that modification and combined reinforcement of aramid-epoxy composites are the most effective methods to increase strength and adhesion to epoxy resin.