The use of recycled polypropylene (RPP) as raw material for various industries has been known. However, the mechanical and thermal properties of recycled products are lower than those of raw material. The objective of this study was to obtain and investigate the modified recycled polypropylene (RPP) with commercial elastomers for possible applications. The compounded RPP-based thermoplastic elastomers were investigated in order to determine their thermal properties (melt flow index (MFI), differential scanning calorimetry (DSC), VICAT softening temperature (VST), and heat deflection temperature (HDT)), structural characteristics (optical microscopy, atomic force microscopy (AFM), and X-ray diffraction (XRD)), and mechanical properties (tensile properties, density, and IZOD impact). The RPP compounded with 10% elastomer recorded higher tensile properties than the unmodified RPP. Also, IZOD impact strength increased from4.3±0.2 kJ/m2(registered for RPP) to21.7±2.5 kJ/m2for the PPR/SIS30 compound, while the degree of crystallinity decreased for all compounds. The obtained results recommend the RPP/elastomers compounds both for environmental remediation from postconsumer PP wastes and to realize new goods with high performance for various applications.

Nowadays, the polyolefins (polyethylene, polypropylene) are increasingly consumed in large amounts for many applications. This issue causes a concern regarding the environmental impact of the waste materials generated after the first use. Mechanical recycling of polyolefin wastes helps to conserve oil and gas resources and reduce the polymeric waste accumulation in environment. In this paper, the modification of some post-consumer polypropylene (rPP) properties coming from packaging processing is investigated by the use of styrene-isoprene-styrene triblock copolymers (SIS). Thus, SIS block copolymers up to 20 wt.% in content with respect to rPP were introduced into the melted polymeric matrix by means of a twin rolls under the processing temperature of 185-190 ºC. The mechanical, thermal and structural properties of rPP/SIS blends have been studied with regard both to the content of SIS from blends and of polystyrene (PS) from SIS. The obtained results showed that the used SIS block copolymers led to the decrease of the degree of crystallinity and to increase of crystallite sizes of blends, with SIS20-10% being the most pronounced effect. Although by introduction of SIS into rPP a slight decrease of tensile strength is recorded, a remarkable increase on elongation at break and impact strength of rPP/SIS blends are exhibited. The good mechanical properties were achieved even by using of 10 wt% SIS.