Recycled carbon fiber reinforced poly(butylene terephthalate) thermoplastic composites: fabrication, crystallization behaviors and performance evaluation

Abstract

The thermoplastic composites based on poly(butylene terephthalate) (PBT) and recycled carbon fiber (RCF) were prepared through simple melt compounding by a twin‐screw extruder. An effective approach was utilized to clean and treat the RCF surface with a concentrated solution of nitric acid and then a solution of diglycidyl ether of bisphenol A as macromolecular coupling agent so as to improve the interfacial adhesion between the RCF and PBT matrix. As a result, the reinforcing potential of the RCF was enhanced substantially, and the mechanical properties, heat distortion temperature, and thermal stability of PBT could be significantly improved by incorporating this surface‐treated RCF. The morphologies of fracture surfaces indicated that the RCF achieved a homogeneous dispersion in the PBT matrix due to a good interfacial interaction between fiber and PBT. The investigations on the crystallization behaviors and kinetics demonstrated that the RCF acted as a nucleation agent for the crystallization of PBT, and the crystallization rate and nucleation density of PBT were increased remarkably due to the heterogeneous nucleating effect of RCF in the matrix. These features may be advantageous for the enhancement of mechanical properties, heat resistance, and processability of PBT‐based composites. This study may provide a design guide for carbon fiber‐reinforced PBT composites with a great potential as well as a low cost for industrial and civil applications. Copyright © 2012 John Wiley & Sons, Ltd.