Effect of pH on The Dispersion Property of Sulphur Nanoparticles in Natural Rubber

Abstract

Sulphur nanoparticles (NPs) have attracted significant research and industry interests, especially in the rubber industry as a vulcanisation agent that is responsible to form cross-links between the rubber chains in the vulcanisation process which will make the natural rubber more flexible and durable. Unfortunately, the main obstacle of direct incorporating sulphur NPs into natural rubber is the agglomeration of sulphur NPs attributed to its high surface energy. The objective of this study is to evaluate the dispersibility and stability of sulphur NPs in natural rubber based on the solution pH 1.5 wt% and 3.0 wt% sulphur NPs were dispersed in natural rubber. The sulphur suspensions were subjected to ultrasonication for 2 minutes in which the pH of homogenised sulphur suspensions was adjusted to the range 6.0-10.0. The results revealed that ultrasonic irradiation was successfully broken the agglomerated rubber particle and produced smaller mean particle size for 1.5 wt% sulphur NPs at pH 8 and 3.0 wt% sulphur NPs at pH 7 with the mean particle size of 366.2 nm and 384.9 nm, respectively. Between both concentrations, natural rubber loaded with 1.5 w% sulphur NPs is a better formulation with better dispersibility of sulphur NPs and smaller mean particle size distribution at pH 8.

Keywords

• sulphur nanoparticles
• natural rubber
• ph
• zeta potential
• particle size distribution