Authors:

Abstract

Ground Tyre Rubber (GTR) from scrap automotive and truck tyres was blended with Waste Polypropylene (WPP) from injection moulded products to prepare GTR/WPP blends. The blends were prepared in a Haake Rheocord PolyLab System, operating at 180 0C and 30 rpm for 8 minutes. The degree of crystallinity of the WPP in the GTR/WPP blend was found to be unchanged up to a GTR level of 60 % by weight. Crystalline melting point and re-crystallization temperature showed a significant decrease with GTR content. Optical micrograph of the blends containing up to 60 wt% GTR showed a similar morphology, in which the GTR was dispersed in a continuous WPP phase. The GTR dispersed phase grew in size with GTR content until at 70 wt%, it changed to a continuous phase. However, all blends showed a mixture of cohesive, adhesive and ductile failures. The response to tensile loading ranged from a ductile plastic response with WPP-rich blends to a high extension–rubbery response with GTR-rich blends. Under impact loads, brittle fracture occurred in blends containing up to 40 wt% GTR, with ductile fracture thereafter. Hardness, tensile strength, secant modulus at 7% strain and tear resistance decreased with increase in GTR content, while % elongation at break and impact failure energy increased.

Keywords: Ground tyre rubber, mechanical properties, rubber thermoplastic blends, waste polypropylene

doi :10.4038/jnsfsr.v37i2.1067

J.Natn.Sci.Foundation Sri Lanka 2009 37 (2):117-123

Keywords: ground tyre rubber, mechanical properties, rubber thermoplastic blends, waste polypropylene