A Method for Preparing Low-Allergen Natural Rubber Latex

Abstract

The free radical polymerization of dimethylaminoethyl methacrylate (DMAEMA) on the surface of particles in natural rubber latex (NRL) was carried out using an iron(ii)/tetraethylenepentamine (TEPA) redox couple initiation system, which results in significant grafting of poly(DMAEMA) to the surface of the particles. Because poly(DMAEMA) functions as an electrosteric stabilizer, this leads to increased colloidal stability, which suggests that the proteinaceous material which normally provides the colloidal stability in NRL can be displaced. This opens the way to preparing barrier products of low allergenicity, because the allergic response from NRL products arises from this proteinaceous material. Dipped and cast films were prepared from the modified NRL and were shown to be of low allergenicity using the IgE-ELISA inhibition assay. Vulcanized films prepared from the modified latex were also found to be of low allergenicity compared to a compounded film of unmodified NRL prepared under similar conditions. The barrier integrity, tensile strength, and elongation at break values of vulcanized films prepared from the modified latex were also equivalent to the unmodified film, and their water sensitivity and ageing characteristics were not significantly different. This suggests that this modified NRL can be used as an effective low-allergy latex for personal barrier products such as surgical gloves.