Strength analysis of carbon fiber reinforced PEEK composites with heat resistant sizing agents

Abstract

Continuous Fiber Reinforced Thermoplastic Composites (CFRTPCs) are known for their demand in high-tech industries due to their excellent mechanical, thermal and chemical performance. However, poor adhesion interaction between carbon fiber (CF) and high-performance polymers such as PEEK tend to influence the mechanical modulus of the composite parts in a negative way. In the current work, a number of PAA-based sizing agents modified with various fillers were used for CF surface treatment in order to improve adhesion. Thus, the wettability of the sizing agents was studied, as well as the free surface energy using the Owens-Wendt method. The calculated energy values were used to determine the work of adhesion between the sizing agents and PEEK. The adhesive connection between the CF treated with the sizing agents and PEEK was examined by the single fiber pull-out testing. Furthermore, the most promising samples were used for CF, on the basis of which towpreg composites samples were obtained to study its physico-mechanical properties. Results suggested that the values of the strength characteristics of the composites are comparable to the values measured for composites based on commercially available materials.