Latex blends of natural rubber and nitrile rubber with chloroprene rubber: improvement in compatibility and properties

Abstract

Latex is a colloidal dispersion of a polymer substance in an aqueous medium. Latex blends of natural rubber (NR) and several synthetic rubber latices (e.g. chloroprene rubber (CR), nitrile rubber (NBR), styrene butadiene rubber (SBR) etc. ) have been used extensively for manufacturing various rubber products including foam rubber and gloves. In NRlNBR latex blend interfacial tension between NR and NBR is very high due to the differences in polarities of the two latices. Therefore the compatibility and hence the miscibility of NRlNBR latex blend is low. In this study an attempt was made to use CR latex as a compatibilizing agent in NRlNBR latex blends. Using FT-IR spectra it was found that addition of CR latex to NRlNBR latex blend has .caused a chemical shift. Hence the properties of NRlNBR latex blend and NRlCRlNBR latex blend were studied. It was found that the tensile strength ofNRlCRlNBR latex blend is greater than NRlNBR latex blend. Further the solubility parameter of CR latex was found to be between NR and NBR. Hence it was found that CR latex can be used to improve the strength and miscibility ofNRlNBR latex blends. The effect of addition of CR latex on other properties of NRlNBR latex blend (water extractable protein content and oil resistance) were studied and it was found that there was no adverse effect on those properties with the addition of CR latex to NRlNBR latex blend. Therefore it can be concluded that CR latex can be used as a suitable compatibilizing agent ~nNRlNBR latex blend.