Epoxidised natural rubber (ENR) latex: an alternative raw material for latex dipped products

Abstract

The utilisation of epoxidised natural rubber (ENR) for latex products is limited due to the inability of the ENR latex to form film through typical coagulant dipping processes. This is due to the low total solid content (TSC) and the presence of the non-ionic surfactant in the ENR latex. To use the ENR latex for dipping applications, concentration process via membrane technology is used to reduce the surfactant level in the latex and increase the TSC of the ENR latex material. The current study focuses on two grades: 25% and 50% epoxidation levels of concentrated ENR latex as starting materials and the typical latex compounding behaviour, such as pH, zeta potential, particle size and viscosity, was also analysed to understand its characteristic. Results, such as pH, zeta potential, and particle size, were acceptable and suitable to be used for dipping purpose and it passed the general latex properties of compounding. The cure measurement, such as chloroform number and total swelling index, showed ENR latex is fully vulcanised after 2 days of maturation. On the aspect of physical characteristics of the ENR 25 and 50 films, it resulted with high tensile strength (23.7 MPa) and met the specification of Standard Malaysian glove (SMG). The ability for dipping was satisfactory as smooth continuous film was formed. Aside from that, oil-resistance test and contact angle were also analysed to understand its resistance to oil upon time and wettability parameter of the ENR films.