Surface modification of diatomite by titanate and its effects on properties of reinforcing NR/SBR blend

Diatomite was surface-modified by titanate. The effects of modification on reinforcing performance of a natural rubber/styrene butadiene rubber (NR/SBR) blend were investigated by adding modified diatomite samples, instead of amorphous precipitated silica, into the NR/SBR blend. With a dosage of titanate at 1.2% (mass fraction) of diatomite, the oil absorption value of modified diatomite reached 1.34 mL/g with a sedimentation time of 6 min in kerosene. Meanwhile, the tearing strength and 300% elongation of NR/SBR increased by 12.6 and 44.0%, while the tensile strength and the elongation at breakage decreased by 25.9 and 11.4%, respectively. The modification increased the hydrophobicity of the diatomite particles. XPS and FTIR analyses suggested that the adsorption between titanate and diatomite was chemical in nature, due to the formation of Si-O-Ti bond.