Physical, Mechanical and Thermal Insulation Properties of Foam Made from Natural Rubber Compounded with Ground Rice Husk

Abstract

This research attempted to prepare thermal insulation material made of naturally occurring products. Natural rubber (NR) foam comprised of ground rice husk as a filler was practically investigated. STR 5L played as a solid commercial NR was mixed with various chemicals on a two-roll mill. Dicumyl peroxide (DCP) and di-nitroso pentamethylene tetramine (Supercell DPT) were employed as curing and blowing agents, respectively. Physical, mechanical and thermal insulation properties of NR composite foams were studied with various particle sizes (mesh 40 and 60) and quantities (0-80 phr) of the ground rice husk. Cure characterization and preparation of all NR compounds were performed at 160 °C. As a result of tensile properties, the bigger particle size (mesh 40) and the highest amount of the ground rice husk at 80 phr resulted in the maximum tensile strength and elongation at break (%) of the NR composite foams. The thermal insulation property of the NR composite foams carried out by ASTM C177 revealed that the lowest thermal conductivity among three representative NR formulations was found to be 0.0862 W/m.K for the NR foam reinforced with the ground rice husk mesh 40 at 20 phr. Closed cell NR composite foam with a smaller amount of ground rice husk particles provides good compressive strength and heat insulation properties but not good tensile properties.