Thermal degradation and flame retarding characteristics of polypropylene composites incorporated with boron mud

A modified flame-retardant boron mud (FRBM) developed from raw boron mud (BM) was incorporated into polypropylene (PP) with organic modified montmorillonite (OMMT) to obtain PP/FRBM and PP/FRBM/OMMT blends. The BM and FRBM were analyzed by XRD, TGA and XRF. The flame retarding characteristics of the composites were studied by LOI and rate-of-burning (RB) tests. The morphology of the charred residues was examined by SEM. XRD reveals that FRBM contains forsterite, cordierite, muscovite, and brucite. The TGA thermograms indicate that FRBM begins to lose weight sharply at 350 °C and FRBM/OMMT at 300 °C. XRF reveals the levels of elements in BM vary at different temperature. The LOI and RB test show that a larger FRBM content gives good flame resistance and the combination of OMMT and FRBM delivers better results. The SEM pictures illustrate that the PP/FRBM/OMMT residues make a thicker charred layer than the PP/FRBM residues.