Effects of a quaternary ammonium salt on the properties of carbon-black-filled natural rubber compounds

The effects of a quaternary ammonium salt, cetyltrimethylammonium maleate ( CTMAM) on the curing characteristics and mechanical properties of carbon-bl ack-filled natural rubber compounds are determined. Results indicate that C TMAM increases the rate of vulcanization to a maximum at 1 phr (part per hu ndred parts of rubber) followed by a decrease as the concentration of CTMAM is further increased. The incorporation of CTMAM also improves mechanical properties such as tensile and tear strengths, tensile modulus, hardness an d resilience, whilst elongation at break shows a decreasing trend. CTMAM al so improves filler dispersion and increases the extent of cross-linking of carbon-black-filled natural rubber compounds. (C) 2001 Society of Chemical Industry.