Abstract:
Rubber plant (Hevea brasiliansis) is a member of the spurge family Euphobiaceae. Milky latex is
extracted from the bark of tree which is basically used industry of dry rubber and latex based.
Durability of rubber product is one of the most important quality character sought by the
customer. Therefore, manufacturers of rubber products try to protect good properties throughout
the consuming time period. Durability of raw rubber product is affected by aging properties. The
degradation of raw rubber with the time is common for most of the rubber based products and as a
result the properties of raw rubber deteriorated and lead to a low product’s performance. Thermal
oxidation is one of factors which badly affect on the aging property of raw rubber products. The
rubber molecular weight of product will be reduced from thermal oxidation (Swanson et al, 1979).
Resistance to thermal oxidation is measured by plasticity retention index. Sole crepe rubber
manufacturing industry always tries to produce higher grade sole crepe. Colour, clearness and
purity are the quality parameters used in grading of sole crepe. The colour of sole crepe rubber is
sole crepe
manufacturing industry under fractionation step, Sodium metabisulfite (enzymatic inhibitor) is
used to prevent enzymatic discoloration (Tillekeratne, et al, 2003). Through this process,
resistance of oxidative components is removed with yellow fraction. Therefore, this research was
carried out to determine the effect of Sodium metabisulfite on plasticity of different selected
rubber clones.
