A LIGHT-MICROSCOPIC METHOD FOR THE CHARAC TERIZATION OF RUBBER CRUMB

This paper presents a light microscopical method for the characterizat ion of particle size, particle size distribution and the surface of ru bber powder; For the first time rubber crumb is examined in a rubber m atrix, specially after mixing and vulcanization. The results of the ch aracterization are discussed in comparison to sieve analyses. The ambi ent-ground rubber powder shows a wide particle size distribution compa red with the cryogenic- and the wet-ground material. Remarkable is a l arge part of very fine particles (<30 mm) which is specific for the am bient grinding process. The examination of the morphology by the linea r fractal dimension alpha shows the highest surface roughness for the wet-ground material and the lowest roughness for the cryogenic-ground rubber. It is interesting to not that light microscopy leads to a deta iled characterization of particle size, particle size distribution and structure of the surface of the rubber powders compared with sieve an alyses.