Effects of Sizing Materials on the Properties of Carbon Fiber-Reinforced Polyamide 6,6 Composites

This article aims to study the effect of the sizing materials type on the mechanical, thermal, and morphological properties of carbon fiber (CF)-reinforced polyamide 6,6 (PA 6,6) composites. For this purpose, unsized CF and sized CFs were used. Thermogravimetric analysis was performed, and it has been found that certain amounts of polyurethane (PU) and PA sizing agents decompose during processing. The effects of sizing agent type on the mechanical and thermomechanical properties of all the composites were investigated using tensile, Izod impact strength test, and dynamic mechanical analysis. Tensile strength values of sized CF-reinforced composites were higher than that of unsized CF-reinforced composites. PA and polyurethane sized CF-reinforced composites exhibited the highest impact strength values among the other sized CF-reinforced composites. PU and PA sized CF-reinforced composites denoted higher storage modulus and better interfacial adhesion values among the other sizing materials. Scanning electron microscope studies indicated that CFs which were sized with PU and PA have better interfacial bonding with PA 6,6 matrix among the sized CFs. All the results confirmed that PA and PU were suitable for CF's sizing materials to be used for PA 6,6 matrix. POLYM. COMPOS., 34:1583-1590, 2013. (c) 2013 Society of Plastics Engineers