An Advanced Study of Quality Improvement of Natural Rubber Products by Drying Methods

Rubber industry relies highly on a great deal of inputs from the natural rubber (NR) source, being one
of the most used rubber material owing to its unique inherent properties. This experimental study was
carried out to verify the quality enhancement of Natural Rubber Products by drying methods and
ascertain to what extent the different methods of drying affected the properties exhibited. During this
study, samples of natural rubber coagulum were obtained and a sample each was subjected to one of
these three methods of drying: air, smoke and oven. The qualities of the dried rubber samples from
the three methods of drying were then investigated. The criterion adopted for quality in this study was
Plasticity Retention Index (PRI), which gave in-sight of the oxidative resistance of natural rubber, a
measure of quality. The plasticity retention index was tested by using the Wallace plastimeter. The
PRI values were calculated for the samples. Results obtained from this study showed that the
qualities of natural rubber samples were actually influenced to different measurable extents
depending on drying methods, as exhibited in the PRI levels. The results further gave basis for our
conclusions that the smoke dried rubber samples had the poorest qualities, having the lowest values
of PRI; followed by the oven and air dried samples respectively in terms of their PRI presented. The
best qualities, being indicated by the highest PRI values. On the basis of results obtained from this
experimental study, it would be recommended that air drying of coagulated natural rubber samples
should be done in preference to the other two alternatives and should be adopted anywhere possible
as the drying method of choice.