Thermal properties of polypropylene/muscovite layered silicate composites: effects of organic modifications and compatibilisers

Polymer-layered silicate nanocomposites containing polypropylene, compatibilisers, muscovite, and organomuscovite were prepared through the hot compression technique. Muscovite particles were initially treated with lithium nitrate, followed by cetyltrimethylammonium bromide, to obtain the organomuscovite through an ion-exchange treatment. Maleic anhydride and polyhedral oligomeric silsesquioxane were used as compatibilisers to modify the polypropylene/organomuscovite nanocomposite systems. The effectiveness of the ion-exchange treatment and the implementations of both compatibilisers were successfully proven using the Fourier transforms infrared, X-ray diffraction, as well as the transmission electron microscopy. The overall thermal properties of the polypropylene/muscovite layered silicate composites were investigated by applying both differential scanning calorimetry and thermogravimetric analysis. It was found that the polypropylene reinforced with organomuscovite recorded higher thermal properties in terms of crystallisation temperature and thermal stability than its counterpart; whereas, the melting temperature and the degree of crystallinity displayed an opposite trend. For the effect of the compatibiliser, it was found that compatibilised polypropylene/organomuscovite nanocomposites recorded higher values of decomposition and crystallisation temperatures than that of non-compatibilised polypropylene/organomuscovite nanocomposites. However, the melting temperature and the degree of crystallinity of compatibilised polypropylene/organomuscovite nanocomposites were slightly lower, as compared to non-compatibilised polypropylene/organomuscovite nanocomposites.