Natural rubber-graft-poly(2-hydroxyethyl acrylate) on cure characteristics and mechanical properties of silica-filled natural rubber composites

The grafting of poly(2-hydroxyethyl acrylate) onto natural rubber (NR-g-PHEA) was used to compatibilize NR composites with silica filler. The NR/silica compounds were prepared with various grafting percentages of NR-g-PHEA (0, 6.5, 10.5, and 14.5%) and fixed amounts of 3 parts per hundred of rubber (phr) NR-g-PHEA and 20 phr silica. The cure characteristics were examined using a moving die rheometer. The physicomechanical properties of NR/silica composites were determined in terms of tensile strength, bound rubber content, and dynamic mechanical analysis. Thermal properties were assessed with thermogravimetric analysis. The results showed that scorch time and cure time tend to decrease with the level of grafting in NR-g-PHEA. The NR-g-PHEA decreased tan δ, whereas bound rubber content in NR/silica compounds increased, which indicates improved silica dispersion in the NR matrix. The mechanical properties improved with level of grafting in NR-g-PHEA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48738.