Cure characteristic and mechanical properties of silica masterbatch prepared from fresh natural rubber latex mixing

Abstract

The production of silica masterbatches with reduced mixing energy consumption and enhanced mechanical properties has been developed. The unit operations in the process are the preparation of silica slurry in the presence of a suitable surfactant (in this case are ammonium laurate and diethylene glycol), the addition of the slurry to the fresh natural rubber latex (NRL) under stirring, coagulation of the mixture by the addition of 5 wt-% formic acid, dewatering of the coagulum and drying in an oven at 60˚C for 48 h to obtain the silica-incorporated NR. The amount of silica in silica/NR masterbatches was also investigated. Cure characteristics and mechanical properties of vulcanisates prepared from the masterbatches were compared with those prepared by a conventional direct mixing method. Silica/NR masterbatches gave higher maximum torque, shorter cure time, greater modulus, tensile strength and hardness due to better filler dispersion evidenced from scanning electron micrograph studies.