Chemical modification of rubber waste and characterization of their blends with natural rubber

Abstract

Ground rubber tyre (GRT) produced by recycling of tyre waste or rejects is used as a filler in the manufacture of tyre components, mainly to reduce the cost. Rubber matrix-GRT compositions generally exhibit poor mechanical properties due to poor matrix-filler adhesion and lack of reactive sites on GRT particle surfaces. Therefore, GRT is modified by employing various types of reclamation processes to enhance mechanical properties. The modified GRT known as reclaimed rubber is widely used as a component in rubber blends in many applications, especially in tyre manufacturing.

This study is focused on developing a cost effective, environmental friendly mechano-chemical reclamation process for GRT to produce reclaim rubber using a readily available amino compound. Initially, influence of the amino compound on rubber compound properties was evaluated and results indicate that it acts as an activator for sulphur vulcanization. Properties of GRT modified with the amino compound indicate that the amino compound acts as a reclaiming agent as well. Comparison of properties of natural rubber (NR) / novel reclaimed rubber blend compounds and revulcanisates with those of the controls reveal that the former can be used as alternatives to the latter in the manufacture of tyre treads. Replacement of 30% of virgin NR in the vulcanisates with the novel reclaimed rubber retains about 65-85% of strength properties, elongation at break and resilience. Abrasion volume loss is at an acceptable level and ageing properties are comparable to those of the 100% virgin NR vulcanisate.

Further, most of the properties of the virgin NR / novel reclaimed rubber composites are comparable to those of the corresponding composites prepared by blending NR with commercially available reclaimed rubbers. Accordingly, the novel reclaimed rubber could be a suitable component to blend with virgin NR in the manufacture of tyre treads with required properties.