Mechanical Properties and Morphology of Natural Rubber/Chloroprene Rubber Blends Filled with Fly-Ash under Thermal and Oil Aging

Abstract

This work studied the properties of natural rubber (NR) / chloroprene rubber (CR) blends using flyash with and without surface treatment by a silane coupling agent (Bis [3-(triethoxysilyl) propyl] tetrasulfide],Couplink89) at 2% wt of silica content in fly ash. The concentrations of fly ash particles in blends were alsovaried taking account of the amount of silica (FASi) content between 0-50 parts per 100 parts of rubbers.The NR contents in NR/CR blends were varied at 0, 10, 25, 50 and 100 %wt. The results showed thattreatment of fly ash particle with silane coupling agent could improve overall mechanical properties exceptfor elongation at break and hardness. Increasing NR contents in NR/CR blends slightly decreased most ofthe mechanical properties for the un-aged samples, while cleary decreased those properties for the agedsamples. Increases in fly ash particle in NR/CR blends tended to improve tensile modulus and hardnesswhile slightly decreases were observed for tensile strength, elongation at breaks and tear properties. Thermalageing slightly improved most of mechanical properties except for tensile strength and elongation atbreak due to post-curing effect. Thermal-oil ageing obviously deteriorated the properties of filled NR/CRvulcanizates, especially for high NR contents. When comparing with commercial CR products in terms ofmechanical properties, the most appropriate formula of filled NR/CR from this work was NR/CR of 25/75blend ratio with 40 phr FASi content.

Keywords : Chloroprene Rubber / Natural Rubber / Fly Ash / Aging