Polymer Testing 22 (2003) 179–183 www.elsevier.com/locate/polytest Material Properties Effects of cetyltrimethylammonium maleate on curing characteristics and mechanical properties of polychloroprene rubber H. Ismail * , Z. Ahmad, Z.A. Mohd Ishak School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia 14300 Nibong Tebal, Penang, Malaysia Received 12 March 2002; accepted 9 May 2002 Abstract The effects of cetyltrimethylammonium maleate (CTMAM) on curing characteristics and mechanical properties of carbon black-filled polychloroprene rubber (CR) were compared with a conventional curative system viz. combinations of ethylene thiourea (ETU), zinc oxide, and magnesium oxide. Results show that the scorch time and cure time decrease as the concentration of CTMAM is increased. However, both properties are comparable to the conventional curative system (control compound) at a concentration of 3 phr. It was also found that CTMAM was capable of functioning as a cross-linking agent for polychloroprene rubber (CR). CR compounds with 3 phr of CTMAM also show comparable tensile strength and hardness to the control compound whereas resilience decreases with increasing CTMAM concen- tration.  2002 Elsevier Science Ltd. All rights reserved. Keywords: Cetyltrimethylammonium maleate; Curing characteristics; Mechanical properties; Carbon black; Polychloroprene 1. Introduction The numerous ingredients used in rubber mixing posed several problems such as inefficient mixing, additional time and energy consumed during processing as well as various side effects. Besides cutting pro- duction costs, a smaller number of ingredients reduces inhomogeneity of the dispersion of these materials into the rubber matrix. Of late, various works have been done in search of a multi-functional additive whose function is to act either in its own right or in synergy with other ingredients without imparting loss in processing charac- teristics and mechanical properties. These include acting as cross-linking agent, activator, accelerator, or other functions all or partly on its own [1–5]. In previous works [6–7], the effects of a quaternary ammonium salt, cetyltrimethylammonium maleate (CTMAM), on the * Tel.: +60-4-593-7788; fax: +60-4-594-1011. E-mail address: hanafi@eng.usm.my (H. Ismail). 0142-9418/02/$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. PII:S0142-9418(02)00067-3 curing characteristics and mechanical properties and its comparison with sulfenamide as an accelerator in carbon black-filled natural rubber compounds were reported. Results indicate that CTMAM increases the rate of vul- canization to a maximum at 1 phr followed by a decrease as the concentration of CTMAM is further increased. The incorporation of CTMAM improves mechanical properties and filler dispersion, and increases the extent of cross linking of carbon black-filled natural rubber compounds. Results also show that CTMAM can func- tion in its own right as an accelerator for sulfur vulcaniz- ation without the presence of zinc oxide and stearic acid as activators. The use of CTMAM without the presence of zinc oxide and stearic acid not only gave good mech- anical properties but was better compared to the use of commercial N-cyclohexyl-2-benzothiazole-2-sulphenam- ide (CBS). In this work the effects of a similar ingredient, cetyltri- methylammonium maleate (CTMAM), on curing charac- teristics and mechanical properties of carbon black-filled