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Currently, crumb rubber derived flooring is a small, but growing sector in the world floor
coverings market. However it is not widely spread in Sri Lanka. Such flooring includes
mats, rolls, sheets, and indoor and outdoor tiles. Among the materials used for flooring,
natural rubber blended with synthetic rubber is one of the low cost and commonly used
ingredients. However, the pristine rubber blends show retarded mechanical properties.
Thus, reinforcement with additives and vulcanization is commonly practiced technique.
In this research the blend of natural and synthetic rubber is reinforced with crumb
rubber and silica nano particles. Both of these additives were prepared from the waste
materials. Thus, this research is focused to introduce a partial solution for waste
management. The idea is analogues to making large particle reinforced composites
such as concretes in which two different sizes of panicles (coarse gravel and sand)
are densely packed with an adhesive (cement). In this study, fine rubber crumbs of
four different sizes in the range of 3.15 mm to 500 rn were prepared by mechanical
grinding. Silica was extracted from rice husk and further purified before preparing the
silica nano panicles by precipitation method. They were further characterized using
Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis.
FTIR peaks confirm the presence of O-H, Si-O and Si-O-Si bonds in nano silica. The
broad peak between 22" and 23° (2) in XRD data revealed that silica nano particles
were in amorphous form. The composite materials were prepared with different ratios
of rubber: silica nano particles: crumb rubber. The samples with same compositions
but different rubber crumb sizes were also prepared. All the composites were further
reinforced by vulcanization with sulfur. The tensile and compression rests were done to
evaluate their mechanical properties.
