ABSTRACT Recycled polyethylene terephthalate (RPET) and recycle polypropylene (RPP) blends filled with a renewable filler, i.e. cockleshell-derived CaCO3 (CS) were prepared as an environmental friendly thermoplastic composite. The effects of CS particle size and content on thermal stability, mechanical performance and flame retardant properties of the blends were investigated. Thermogravimetric analysis was performed to elucidate the thermal decomposition kinetics of the filled composites. The iso-conversion of the Flynn-Wall-Ozawa was developed by the second order polynomial function for thermal oxidative degradation of the blends while peak derivative temperature from the Kissinger method was able to verify the mechanism of degradation in these blends. The results indicated that both CS and commercial grade CaCO3 improved thermal stability and enhanced the stiffness as well as impact performance of the blends. However, this could only be achieved when high filler content was present in the RPET/RPP blends.
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