Study of physical and chemical properties of chlorinated latex films

Abstract

There has been a wide speculation of the protein allergy in powdered gloves. It has caused some countries to replace the natural rubber latex with synthetic lattices. The experiments have shown that chlorination is a good answer to the protein allergy problem in the production of powderless gloves. The level of chlorination varies from one manufacturer to another. There aren't enough research to prove the optimum chlorination level with regard to different physical properties. This research was done to fill this void. The research was focused on finding tensile strength and friction coefficients at various chlorination levels. Further analysis was done on surface topology and extractable protein content for selected samples. The films were prepared from prevu1canised natural rubber latex. The chlorination was done by using a solution of sodium hypochlorite with 1% m/m hydrochloric acid. The dried prevulcanised latex films were chlorinated at different concentrations with different immersion times. Tensile strength was checked for all the films by using Hounsfield HI0KT Electronic tensile testing machine. Friction coefficient was found for all the films according to the ASTM standard. The surface topology was observed for selected samples from transmitted light of the OPTIPHOT-POL microscope. Finally extractable protein content was found from BCA enhanced protocol method for selected samples. The results showed that there is a cyclic pattern for the variation of tensile strength and friction coefficient with the time of chlorination. The chlorine concentration of 1150 ppm was selected as a suitable concentration which showed better results, The chlorination time of 12 minutes was selected as a suitable time which gave better results. The surface topology of these selected samples revealed that the removal of excessive compounding ingredients, surface hardenings and surface cracks increase with the level of chlorination. These factors have an effect on the films. The surface cracks can cause leakage of the film. The extractable protein content reduces with the increase of chlorination level. However it is necessary to do an analysis from Fourier transform Infra-red (FTIR) spectrometer on the formation of different bonds during the chlorination reaction. Since the facilities were not available it was not possible to perform the FTIR test. The overall results showed that chlorine concentration of 1150 ppm at 12 minutes is the optimum chlorination level. However an efficient leaching system has to be performed to further reduce the extractable protein content of the films. The chlorination system can be further improved by using the chlorine gas system instead of the acidified Sodium Hypochlorite solution.