Feasibility of Utilizing a Thermoplastic Elastomer Seal Made from a Natural Rubber Blend with Recycled Polypropylene from Packaging Waste

This study explores the feasibility of utilizing a thermoplastic elastomer seal made from a blend of rubber and recycled polypropylene (PP) derived from disposable plastic bottles. Thermoplastic elastomers develop by blending natural rubber (NR), epoxidized natural rubber (ENR), and maleated natural rubber (MNR) with PP in a 60/40 rubber-to-PP ratio. The results indicate that NR exhibits superior tensile strength, tear resistance, and compression set compared to ENR and MNR, attributed to NR's crystallization upon stretching and its inherent high elasticity. Both NR and ENR demonstrated good ozone resistance with no observed cracking, while MNR showed the lowest resistance, evidenced by visible cracks after the ozone explosion. NR emerged as the most suitable rubber for thermoplastic elastomer preparation, outperforming ENR and MNR. Comparative analysis between the prototype and commercial products revealed that the prototype's mechanical properties, ozone resistance, and thermal degradation resistance were largely comparable to those of the commercial counterparts. However, to improve flame resistance, further development is needed, particularly through the incorporation of flame-retardant additives.