The Effect of Bis-(3-triethoxysilylpropyl)-Tetrasulfane and Polyethylene Glycol on the Properties of Natural Rubber/ Mica Composites
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
The bis-(3-triethoxysilylpropyl)-tetrasulfane (Si69) is widely applied as a coupling agent to rubber-
filler interactions in silica filled rubber composites. In this study, the effect of bis-(3-
triethoxysilylpropyl)-tetrasulfane (Si69) and polyethylene glycol (PEG) on the properties of natural
rubber (NR)/mica composites has been studied. The mica loading and the total weigh of Si69/PEG
were kept constant at 30 phr and 2 phr, respectively. A composite free from Si69/PEG (SP00) was
used as the control, while ratios of the above chemicals (Si69: PEG) were varied as 1:0, 0:1 and 1:1
in the other composites. These three systems were denoted SP10, SP01 and SP11, respectively.
Curing characteristics, physico-mechanical properties and thermal degradation of NR/mica
composites were investigated. The maximum cure time (Tc90) and scorch time (TS2) were exhibited in
the SP10 compound. However, introduction of PEG into the system with Si69 in SP11 composite
yield a reduction in Tc90 and TS2, which were comparable with the control (SP00). Maximum tensile
strength and elongation at break were observed in Si69 treated NR/mica composite (SP10). This
could be attributed to the improved rubber-filler interactions caused by incorporation of higher
amounts of Si69 (2 phr). Further, the composite treated with both Si69 and PEG (SP11) with 1 phr
each, has shown the second highest tensile strength among candidate composites. However, the
enhanced moduli values at 100%, 300% and 500% elongation indicated better rubber-filler
interactions in SP11 composite than SP10. The same reason may have resulted the highest hardness
and resilience values in SP11 composite. The thermogravimetric analysis indicated that the
application of Si69 and/or PEG have no significant impact on the thermal degradability of NR/mica
composites. It was also found that SP01 exhibited the highest swelling ratio among all samples.
Therefore, overall results indicated that PEG/Si69 treated system (SP11) could be employed more
effectively than individual use of Si69 and PEG to optimize the cure characteristics, while improving
the physico-mechancial properties of NR/mica composites.
Keywords: Mica; Natural rubber composites; Polyethylene glycol; Coupling agent; Rubber-filler
interactions
Description
Keywords
Mineral Sciences, Materials Sciences, Natural Rubber, Geochemistry, Geochemical