Evaluation of biocompatible palm-based polymeric surfactants for potential natural rubber latex stabilisation applications

Studies on environmental-friendly surfactants are essential to potentially replace those highly toxic and non-biodegradable commercially available surfactants. Two biocompatible polymeric anionic (AS1) and nonionic (NS1) surfactants were successfully synthesised from palm oil derivatives via polyesterification. The cytotoxicity of surfactants was measured by in vitro succinate dehydrogenase activity (MTT assay). Results revealed that both surfactants achieved cell viability above 80% against human keratinocytes (HaCaT), mouse fibroblasts (3T3), mouse hepatocytes (H2.35) and canine kidney cells (MDCK) in both dose- and time-dependent manners. Antimicrobial potential of both surfactants was evaluated using minimum bactericidal concentration (MBC) assay. Results indicated that AS1 had a significant antimicrobial activity against most of the tested Gram-positive bacteria. Meanwhile, only one of the Gram-negative bacteria (Acinetobacter baumannii) was successfully reduced by NS1. Both surfactants were subsequently compounded into natural rubber latex (NRL). From rheological study, AS1 exhibited better viscosity behaviour with longer linear viscoelastic region (LVR) towards high ammonia (HA) NRL, signifying its potential in providing stability in the latex environment.