Studies on the improvement of compatibility in reinforced polypropylene composites using polypropylene-g-anhydride itaconate

We prepared long carbon fiber (LCF)-reinforced thermoplastic composites using a new compatibilizer, anhydride itaconate-grafted polypropylene (PP-g-AI). For a good grafting ratio of anhydride itaconate (AI) onto polypropylene (PP), we found optimum mixing conditions such as mixing temperature, monomer content, and initiator type. The initiator, 2,5-dimethyl-2,5-di(tert-butyl peroxy)-hexane (Luperox 101), showed the best graft ratio. The optimum reaction temperature, initiator content, and monomer content were found to be approximately 190°C, 1 phr, and 5 wt%, respectively. We characterized the structure of PP-g-AI using Fourier transform infrared spectroscopy. The ultimate tensile strength of LCF/PP-g-AI/PP composites increased by approximately 15% as the PP-g-AI content increased up to 5 wt%, compared with that of the PP/LCF composites. The fractured surfaces of PP/PP-g-AI/LCF composites showed that PP-g-AI was effective in improving the interfacial adhesion between LCF and the PP matrix.