Effect of urea-based activators on reinforcing activity of silica in natural rubber-based compounds

Abstract

Silica-filled rubber compounds has a high demand for making white and colored rubber products. Silica-filler has high reinforcing ability compared to other white-fillers. Traditionally, polyethylene glycol (PEG) is used to block the acidic silanol groups covering the surface of silica to prevent agglomeration of filler. The present research made an attempt to replace PEG with commercially available urea-based activator Rhenofit-1987. Similar to PEG the Rhenofit-1987 structure includes hydroxyl groups. Additionally, it has amine groups which accelerate vulcanization by building additional links with rubber. To check the reinforcing activity of Rhenofit-1987, the series of Natural rubber-based silica-filled compounds were prepared by partially and fully replacing PEG with Rhenofit-1987. Obtained test results showed improved tensile and tear strength of compounds consisting of Rhenofit-1987 which confirm that Rhenofit-1987 has better reinforcing activity of silica than PEG.