Graft copolymers of microcrystalline cellulose as reinforcing agent for elastomers based on natural rubber

In the present study, free radical graft copolymerization of acrylic monomers and microcrystalline cellulose (MCC) was applied to develop a biopolymer for natural rubber reinforcements. The copolymerization was carried out in aqueous media. Cerium ammonium nitrate was employed as the initiator in the presence of nitric acid. Acrylic monomers used in the copolymer synthesis were ethyl acrylate (EA) and butyl acrylate (BA). Effects of monomer concentration, initiator concentration, polymerization time, and polymerization temperature on the obtained graft copolymers were investigated. The graft parameters were obtained by thermal gravimetric analysis method. The obtained copolymers (MCC-g-PEA, MCC-g-PBA) were characterized by attenuated total reflection, wide-angle X-ray diffraction, field-emission electron microscopy, and thermal gravimetric analysis. In comparison to native MCC, better thermal stability of graft copolymers were observed. In addition, the graft copolymers reinforced natural rubber composites were produced, and sulfur was used as the vulcanizing agent. Their vulcanization and mechanical properties were characterized. Comparing to the native MCC reinforced natural rubber composites, the copolymers reinforced natural rubber composites shows improved mechanical properties, indicating the copolymer's potential application as rubber reinforcements.