RECLAIMING OF GROUND RUBBER TIRE BY SAFE MULTIFUNCTIONAL RUBBER ADDITIVES: I. TETRA BENZYL THIURAM DISULFIDE

Abstract

ABSTRACT The present paper describes the mechanical reclaiming of ground rubber tire (GRT) by safe tetra benzyl thiuram disulfide (TBzTD), a multifunctional rubber additive. The versatility of the proposed agent is that it acts as a reclaiming agent during reclaiming and as a curing agent during revulcanization of the reclaimed materials. In this regard, we want to introduce a safe reclaiming agent in reclamation of GRT for improving its physical and mechanical performance. Reclaiming GRT has been carried out in an open roll mixing mill at various time intervals and different concentrations of the reclaiming agent (TBzTD) in the presence of spindle oil. The degree of reclaiming has been evaluated by the measurement of sol content, gel content, Mooney viscosity, inherent viscosity of sol rubber, and degree of cross-link of the reclaimed materials as a function of milling time. Also, the influence of gel content on cross-link density at various time intervals on the open two roll mixing mill has been determined. A unique correlation between gel fraction and cross-link density obtained at various time intervals and concentrations of reclaiming agent indicate that an optimization of the concentration of safe TBzTD and milling time has a positive influence on improving the efficiency of reclamation. The reclaiming conditions have been optimized in view of the mechanical properties of the revulcanized GRT and the aging resistance properties of the revulcanized reclaim. The influences of the concentration on the mechanical properties in the revulcanized reclaim have also been studied. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the revulcanized reclaimed rubber when reclamation is carried out by optimum concentration of safe TBzTD after maximum time of reclaiming.