The swell ratio is a measure of solvent resistance of a material.
The effect of CTS loading on the toluene absorbency is shown in
Fig. 8. It is obvious from the results that the swell ratio value decreases
as a function of CTS loading. A decrease of around 50% is
observed for the highly filled CTS (20 phr). This can be explained
due to the formation of a CTS network within the vulcanized rubber
which decreases the diffusion of solvent into the rubber. It can also
result from the strong interface between the CTS and the rubber,
constraining the swelling of the polymeric chains located in the
interfacial zone [20]. Furthermore the ability of the filled rubber
biocomposites to swell in toluene is also due to the behaviour of the
filler itself. It was found that CTS and most of its derivatives are
insoluble in organic solvents [21] as reported and proven by our
current study. It was found CTS can only absorb about 12% of
toluene. Therefore that is also an indicator that the toluene absorbency
decreases with CTS loading.