Microwave heating has been used in rubber industry for in vulcanizing rubber compounds for quite sometimes. Due to its comparatively faster heating than conventional heating, it gain its place in certain production fields. Taking this factor into consideration, utilization of microwave in foaming natural rubber has been explored and it was found that using only water/moisture, dry NR can be successfully foamed using microwave radiation. Images of the produced foams are presented below with respect to days of immersing the rubber compound in water.
It was quite surprising that an open cell structure was obtained and this marks a new mileage for the production NR foams which usually yielded a more dominant closed cell structure.