Influence of constituents on thermal properties of polymethacrylate derivatives-clay materials

Abstract

In this study, the solution-mixing method was used to prepare polymethacrylate derivatives' (PaMAs) nano-composites with kaolinite. It was observed that the resultant materials could include exfoliated, intercalated, and undispersed kaolinite depending on their XRD patterns. TEM micrographs also revealed that platy and tube structures of kaolinite and their stacked form would disperse in the PaMAs. Therefore, they were called PaMAs-kaolinite materials with mixed morphology. The effects caused by different types of PaMA, solvent, and clay (sepiolite and kaolinite) on the thermal properties of these materials were examined. When the thermal stability of the materials was compared on the basis of the functional groups in the PaMAs, it was seen that the materials of the linear PaMAs with kaolinite usually had better thermal stability than that of the ring PaMAs and also seen that the thermal stability of Kao-PaMAs increased from PMMA to poly(ethyl methacrylate) (PEMA) and poly(butyl methacrylate) for linear PaMAs. The solvent type affected the thermal stability and the glass transition temperature of the PaMAs. It was found that THF is the most suitable solvent for increasing thermal stability of the PaMAs in the presence of kaolinite; however, it is difficult to say the same about their T(g) temperatures. In addition, the thermal stabilities of PEMA and poly(2-hydroxylethyl methacrylate) were higher in the presence of kaolinite in comparison with sepiolite. The results obtained in this study were explained by the utilization of the relationships among their solubility parameters and of the interactions among the PaMAs, clays, the modifier (octadecylamine) and solvents.