A novel surface modification for calcium sulfate whisker used for reinforcement of poly(vinyl chloride)

A novel technique is developed in this study to modify the surface of calcium sulfate whisker (CSW) for the preparation of high-performance CSW/poly(vinyl chloride) (PVC) composites. The CSW coated with poly(vinyl alcohol) (PVA) and then cross-linked by glutaraldehyde is used to strengthen PVC, and the surface morphology and mechanical properties of CSW/PVC composites are investigated. It shows that the mechanical properties of the cross-linked PVA modified CSW/PVC (cPVA@CSW/PVC) composites are significantly improved, their yield strength, breaking strength, tensile modulus and elongation at break are 65.7 MPa, 53.5 MPa, 1772 MPa and 225 %, with an increase of 7.2, 13.1, 7.6 and 8.2 % as compared with that of the unmodified CSW/PVC composites, respectively. The improvement in the mechanical properties can be attributed to the strong interfacial adhesion between cPVA@CSW and PVC matrix, because the modified CSW has abundant hydroxyl groups that can produce a strong interaction with PVC. This method is simple and inexpensive, and can be applied in large scale.