Ethylene-propylene-diene rubber (EPDM) and isobutylene-isoprene rubber (IIR) were
compounded, precured to a low degree, and then were blended with natural rubber (NR).
The compounding ingredients for NR were then added and the final curing was done. NR/
EPDM and NR/IIR blends, prepared using this method, were found to possess much
improved mechanical properties as compared to their conventional counterparts. The optimum
precuring crosslink density that has to be given to the EPDM and IIR phases has
been determined.
Rani, Joseph(OPA (Overseas Publishers Association), May 28, 1995)
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Abstract:
Amine Terminated Liquid Natural Rubber (ATNR) was used as a plasticiser in filled NR and NBR
compounds replacing oil/DOP. The scorch time and cure time were found to be lowered when ATNR
was used as the plasticiser. ATNR was found to improve the mechanical properties like tensile strength,
tear strength and modulus of the vulcanizates . The ageing resistance of the vulcanizates containing ATNR
was superior compared to the vulcanizates containing oil/DOP.
Filled compounds of natural rubber, isobutylene-isoprene rubber
and styrene-butadiene rubber compounds were extruded through a laboratory
extruder by varying the feeding rate at different temperatures and revolutions
per minute. The extruded compounds were vulcanized up to their optimum cure
times and the mechanical properties of the vulcanizates were determined. The
properties suggest that there is a particular feeding rate in the starved fed region
which results in maximum mechanical properties. The study shows that running
the extruder at a slightly starved condition is an attractive means of improving
the physical properties.