Mechanical and thermal properties of NR/XSBR composite reinforced with rice husk silica

Abstract

Natural rubber (NR) is a renewable resource that is used in many products. In the production of NR products, other rubbers or fillers may be used to produce a product with required properties. However, most rubbers and fillers are synthetic which are non-environmentally friendly materials. To solve this problem, rice husk ash (RHA) from biomass power plant was used to prepare silica to be used as a filler in rubber by in-situ generation. The purer RHA was prepared by leaching with HCl to remove some metallics and increase silica contents by combustion. The purer RHA was dissolved in NaOH to obtain sodium silicate from RHA (RSS). Carboxylated styrene-butadiene rubber (XSBR) used as synthetic rubber was blended with NR in latex form. NR/XSBR at the ratio of 2:1 was mixed with RSS to obtain NR/XSBR/RSS mixture. Acetic acid was dropped into the mixture until neutral for precipitating silica to obtain NR/XSBR/RSi composite. The mechanical, morphological, and thermal properties of NR/XSBR/RSi composites at different contents of silica (5, 10, and 15 phr) were studied. The NR/XSBR/RSi composite with optimum content was compared with NR/XSBR/CSi composite which prepared silica from commercial sodium silicate (CSS) on mechanical, morphological, and thermal properties.