Synthesis of new polyether titanate coupling agents with different polyethyleneglycol segment lengths and their compatibilization in calcium sulfate whisker/poly(vinyl chloride) composites

Six new polyether titanate coupling agents with different polyethyleneglycol (PEG) segment lengths were prepared in this study and were then used to modify calcium sulfate whiskers (CSWs) in order to improve the compatibility between CSWs and poly(vinyl chloride) (PVC). The chemical structure of these coupling agents was characterized by FTIR, Raman, H-1 NMR and P-31 NMR, and the surface properties of CSWs modified by the coupling agents (mCSWs) were characterized by FTIR, SEM-EDS and XPS. Then, CSW/PVC and mCSW/PVC composites were prepared using a two-roll mill, and their mechanical and thermal properties were characterized to investigate the effects of the PEG segment length of the coupling agents on the performance and compatibility of the composites. The results show that the new coupling agents can significantly improve the compatibility and the interfacial adhesion between CSWs and the PVC matrix, which results in a significant improvement of the comprehensive performance of mCSW/PVC composites. PEG4000 shows the best modification effect on CSWs. Finally, the underlying mechanisms are discussed.