Functionalization of used tire rubber (UTR) via hydrosilation and modification of epoxy matrix by hydrosilated UTR

The stockpiling of scrap tires around the world has reached new heights, and though a major portion of these tires have found some end use application (most of them being burnt as fuel), they still pose a variety of environmental and health issues. Moreover, crumb rubber powder, in the form of fillers for asphalt and a variety of polymer matrices accounts for only a minor portion of the market share for scrap tires. Hence, there is a pressing need to increase the utilization of crumb rubber.; Recycling of Used Tire Rubber, heretofore abbreviated as UTR, in the ground form is attempted by developing a novel surface modification route. This work deals mainly with surface modification by hydrosilation. A secondary functionalization of the hydrosilated UTR surface is demonstrated to enhance the compatibility of UTR with different matrices. The final part involves the incorporation of hydrosilated UTR into an epoxy matrix and focuses on the interaction between hydrosilated UTR and the epoxy.; The hydrosilation of UTR is accomplished by using Karsted's catalyst to attach trichlorosilane across the carbon -- carbon double bond present in UTR, followed by hydrolysis to get silanol functionality on the UTR surface. This was achieved under a variety of reaction conditions. Solid state 13C nuclear magnetic resonance (NMR) and attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopies show evidence of hydrosilation. The hydrosilated rubber was also characterized by EDX and thermal analytical tools like differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A unique finding, that the UTR undergoes hydrosilation even without a platinum catalyst, was also investigated using model studies on the hydrosilation of squalene.; Further functionalization of hydrosilated UTR (secondary modification) has also been performed. 3-(N-strylmethyl-2-aminoethylamino)-propyltrimethoxysilane was used as the secondary silane to introduce a styryl functionality onto the hydrosilated UTR and characterized by spectroscopic techniques like solid state 13C NMR, ATR-FTIR and EDX.; The hydrosilated rubber was incorporated into an epoxy matrix to toughen the matrix and evaluate its compatibility. Composite sheets of epoxy and UTR (both hydrosilated and unmodified) were made in a compression mold using diethylenetriamine as the curing agent. The composite specimens were characterized by dynamic mechanical analysis (DMA), tensile testing and scanning electron microscopy (SEM). Additionally, the change in the activation energy of the epoxy glass transition as a result of adding UTR was also measured. It was observed that hydrosilated UTR had better interaction with the epoxy matrix than the untreated UTR. This specific interaction resulted in lowering the glass transition temperature of the epoxy phase and the activation energy of the glass transition.