In the present work, we used the steam explosion method for the isolation of cellulose nanofiber (CNF) from Cuscuta reflexa, a parasitic plant commonly seen in Kerala and we evaluated its reinforcing efficiency in natural rubber (NR). Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA) techniques indicated that type I cellulose nanofibers, with diameter: 10–30 nm and a 67% crystallinity index were obtained by the proposed method. The results showed that application of CNF in NR based nanocomposites resulted in significant improvement of their processing and performance properties. It was observed that the tensile strength and tear strength of NR/CNF nanocomposites are found to be a maximum at 2 phr CNF loading, which corresponds with the studies of equilibrium swelling behavior. Dynamic mechanical analysis, thermogravimetric analysis, and morphological studies of tensile fractured samples also confirm that CNF isolated from Cuscuta reflexa plant can be considered as a promising green reinforcement for rubbers.

Fillers play a dominant role in modifying the properties of the base polymer. Precipitated silica is a promising non-black filler for rubber vulcanisates. As silica is hydrophilic and rubber is hydrophobic, uniform dispersion of silica in rubber is difficult and gives rise to problems such as high initial viscosity. Silica has a number of hydroxyl groups, which result in filler–filler particle agglomeration and reagglomeration. Incorporation of silica into rubber is quite difficult compared with the incorporation of carbon black. The main aim of this study was to reduce the hydrophilicity of silica by coating antioxidant onto its surface, and hence achieve easy incorporation of silica into rubber. The preparation of antioxidant-modified precipitated silica and its use as filler in rubber compounds were investigated. The curing and mechanical properties of the compounds were compared with those of conventional compounds containing unmodified silica and antioxidant in the same dosage on natural rubber. The cure and mechanical properties were found to be superior for modified silica composites compared with unmodified silica composites.