Recycled polypropylene with improved thermal stability and melt processability

Abstract

Polypropylene (PP) is a versatile polymer, with a wide range of applications, from household appliances to packaging and automotive components. Unfortunately, most of the PP products have a short life, which leads to a large amount of plastic waste. Recycling PP is an efficient way to offset the environmental pressure, and several technical solutions have been already proposed for PP recycling. However, dramatically reduced thermal and mechanical properties are generally obtained in the case of PP waste materials. In this work, the influence of PP waste on thermal and mechanical properties of PP waste/virgin PP blends was studied. A PP waste material (PPRR) was melted and compounded with high flow virgin PP homopolymer. The blends were characterized by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, mechanical tests and Fourier transform infrared spectroscopy. An increase by 20% of the tensile strength and modulus and 2.5 times increase in the melt flow index were observed in the case of the blend with 50% virgin PP as compare to PPRR, also an important increase in crystallinity. All the blends showed a better thermal stability than the virgin PP. The results recommend the blends with 30–50% virgin PP for the recycling of PP waste from raffia in high-performance applications.