Abstract: A carbonized diatomite was prepared by calcining Inner Mongolia diatomite rich in organic matter under reducing atmosphere. The carbonized diatomite was partly substituted for carbon black to reinforce natural rubber (NR). Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), thermoanalysis (TG-DTA), scanning electron microscope (SEM), energy-dispersive spectrometer (EDS) and mechanical properties test were employed to character the resultant carbonized diatomite and NR vulcanizates. The results showed that the organic matter in diatomite could be translated into amorphous carbon adsorbed on the surface of diatomite and in the micropore of diatomite after 600oC calcination under reducing atmosphere. Because the carbon in carbonized diatomite could improve the compatibility between diatomite and NR, the introduction of carbonized diatomite into NR matrix could enhance the mechanical properties. When 25wt% carbon black was replaced with carbonized diatomite, the tensile strength and tear strength of NR vulcanizates was significantly improved.

Key words: Diatomite, Rubber, Mechanical properties