Synergistic effects of styrene grafting and cellulose reinforcement on thermal and mechanical properties of deproteinized natural rubber

Abstract This study investigated the possibility of integrating natural rubber (NR) with various forms of cellulose (Cell) to develop new composites that enhance physical properties. For the first time, the innovative composites were fabricated from blending the modified deproteinized natural rubber (DPNR) by a graft copolymerization process using styrene as the continuous phase and cellulose as the reinforcing phase. Cellulose interacts with rubber segments, leading to improvements in heat resistance and tensile strength in comparison with NR. Herein, microcrystalline cellulose (MCC) and cellulose nanofiber (CNF) are the two cellulose forms utilized. The particle size and the amount of the cellulose have an impact on the thermomechanical properties of the composites. Both MCC/DPNR‐g‐PS 1% and CNF/DPNR‐g‐PS 1% demonstrated an improvement in mechanical properties over conventional DPNR and DPNR‐g‐PS. Notably, tensile strength increased threefold for MCC/DPNR‐g‐PS 1% (6.52 ± 0.31 MPa) and fivefold for CNF/DPNR‐g‐PS 1% (11.97 ± 0.34 MPa) compared to DPNR (2.09 ± 0.12 MPa). Furthermore, the glass transition temperature increased by 1.31°C for MCC/DPNR‐g‐PS 1% and by 1.34°C for CNF/DPNR‐g‐PS 1% compared to DPNR, indicating improved thermal stability. The decomposition temperature also increased for both composites. These findings showed that the novel structural formation of Cell/DPNR‐g‐PS composites offers promising alternatives to conventional vulcanized NR reinforced with sulfur, carbon black, or silica. The improved thermomechanical properties of these composite materials make them potential candidates for various applications. Highlights A novel composite material fabricated from renewable natural resources. Cell/DPNR‐g‐PS thermal‐mechanical properties are enhanced in comparison to NR. Graft copolymerization improves DPNR interaction with cellulose. The size and content of cellulose impact the properties of Cell/DPNR‐g‐PS.