Green preparation and characterization of a novel heat stabilizer for poly(vinyl chloride)–hydrocalumites

Abstract

Hydrocalumites are successfully prepared by using Ca(OH)₂, Al(OH)₃ and Na₂CO₃ with different reaction times and crystallization times. The as-prepared samples are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that the as-prepared sample with the reaction time and crystallization time both being 4 hours can be seen as pure hydrocalumite, and shows higher crystallinity and more regular crystals than the other samples. The different as-prepared samples were mixed with PVC resin. Thermal aging and Congo red test of the resulting PVC composites were carried out in a thermal aging test box at 195 ± 1 °C. The results show that all the as-prepared samples used as single thermal stabilizers could enhance both the long-term thermal stability and initial thermal stability of PVC. Especially, the as-prepared sample with the reaction time and crystallization time both being 4 hours has better thermal stability than the other samples. And thermal aging tests of PVC with varying amounts of hydrocalumites shows that 4 phr is the optimum amount of hydrocalumite filler.