Abstract:
Use of reclaimed rubber as a component of a blend with virgin rubber or as a
replacement for the virgin material in most rubber applications, especially in tyre
components, has increased in the recent past. This is due to the increase in
prices of natural and synthetic rubbers and growing concern about environmental
issues. This research is aimed at evaluating the properties of rubber compounds
produced by blending virgin natural rubber (NR) with ground rubber tyre (GRT),
which was modified using a readily available, environmentally friendly, low-cost
amino compound. Initially, reclaiming of 40 mesh GRT in the presence of rubber
processing oil was studied at four different concentrations of the amino compound
and two milling time periods. Mechanochemical reclaiming/devulcanisation was
performed at a temperature of 30–70°C, using a laboratory two-roll mill. Properties
such as initial plasticity, swelling ratio, crosslink density, and molecular weight
between two crosslinks (Mc) of the reclaimed rubber samples were evaluated.
Rubber compounds were prepared in the second stage by blending the reclaimed
GRT samples with virgin NR in a ratio of 15:85. Mooney viscosity, initial plasticity,
cure characteristics, and dynamic properties of the above blend compounds
were evaluated and compared with those of the control compounds. This study
shows that the amino compound acts as a devulcanising/reclaiming agent for
GRT. Rubber compounds prepared by blending virgin NR with novel reclaimed
rubber exhibit higher stock viscosity, lower scorch resistance, and lower hysteresis
in comparison with the control compounds.