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.
