In situ suspension polymerization of vinyl chloride/3-(trimethoxysilyl) propyl methacrylate (MPTMS) intercalated Mg-Al-layered double hydroxide: II. Morphological, thermal properties and diffusion behavior

Abstract

A series of PVC composites were produced using an in-situ suspension polymerization method with an optimal amount of 5 wt% of MgAl(NO3) layered double hydroxide (LDH) or LDH-MPTMS, which is MPTMS-intercalated Mg-Al LDH. The physical, mechanical, and thermal properties of the composite samples were compared to pure PVC. Results from the Brabender® plastograph showed that the PVC grains produced with LDH-MPTMS had a longer thermal stability time and shorter fusion time. The addition of LDH-MPTMS nanosheets increased the gelation degree of PVC particles, resulting in a lower temperature/time requirement for processing. The thermal stability of the composite material was confirmed through a standard dehydrochlorination test, which demonstrated a 40% improvement in dehydrochlorination rate compared to pure PVC. This improvement was 12% higher than that observed in the PVC/LDH composite. TGA curves indicated a significant increase in the 5 and 50% weight loss temperatures of PVC resins with the addition of 5wt% LDH or LDH-MPTMS, with an approximate growth of 11°C. The glassy state storage modulus and Tg of the PVC/LDH-MPTMS composite were higher than those of pure PVC and the PVC/LDH composite. Mechanical analysis revealed that the PVC/LDH-MPTMS composites exhibited greater stiffness and toughness, as well as significantly higher Charpy notched impact strength, tensile strength, and Young’s modulus compared to both the PVC/LDH composite and pure PVC.