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Recently, blending of polymers has become an increasingly important area of
research activity. Elastomeric blends are used for many reasons such as lowering the
compound cost, for ease of fabrication and to improve the performance of the
industrial rubber. Natural rubber (NR) and styrene–butadiene rubber (SBR) have been
blended for a long time for these reasons. In this study, 12 different rubber compounds
were prepared by using SMR-20 type of natural rubber and SBR-1502 type of
styrene–butadiene rubber in different proportions, keeping fixed the total rubber
quantity specified in the standard testing recipe. The mechanical and physical
properties – such as tensile strength, hardness, wear, carbon black, ozone resistance,
density and rheological properties of the present industrial rubber – were studied.
Physical and mechanical test results were reported. The tensile, hardness and wear
properties of the NR/SBR blends with the increment of NR percentages were greatly
enhanced. The study also indicated that filler materials affect on the physical and
mechanical properties of the blends.
Blending of two or more types of polymer is a useful technique for the
preparation and developing materials with properties superior to those of individual
constituents. It is important especially from an industrial point of view to control the
state of mixing of polymer blends. An adequate polymer-blend process requires
information and understanding of the blend behavior under production conditions.
The knowledge of the relationship among melt viscosity, elasticity, and pressure and
process temperature is important for the design appropriate process equipment and for
assessment of the optimum process conditions to produce materials that have required
properties. Natural rubber has been studied and reported on extensively because of its
superior performance in tire applications. It is well installed that elastomers do not
display all of the characteristics that are required. Elastomeric blends are used for
many purposes such as lowering the compound cost. The complex shaped product
may be more easily fabricated during production. Natural rubber (NR) and
styrene–butadiene rubber (SBR) have been blended for along time for these reasons.
A lot of studies have demonstrated that the mechanical properties of such blends can
be significantly improved by adding a suitable compatibiliser. NR blending has been
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widely studied and reported as good compatible blends that provide desirable
mechanical properties. Another paper about the development of novel elastomeric
blends containing NR and ultra-low-density polyethylene (ULDPE) reported by
Tanrattanakul and Udomkichdecha. Conventional vulcanization was performed and
the physical and mechanical properties of the blend were determined. The results were
compared with those obtained from NR blending with SBR. Blending SBR with NR
can improve the tensile strength because NR crystallizes on stretching. Kim
investigated the mechanical properties of NR blended with SBR. Those study
indicated that the mechanical properties of this blend were required reinforcement.
Thus, filled polymer systems are very popular for the industry for both cost and
performance objectives. It is also well established that carbon black (CB) is one of the
most important classical reinforcing fillers, especially for the rubber technology for
cheaper Vulcan sates. New materials are also considered as fillers, whether for more
economical reasons or rather to impart some desirable characteristics of CB as one of
the major inputs in tire industry, has some extraordinary features. Surface area of CB
is one of the most critical parameters considered for degree of reinforcement, which
supply necessary sites to polymer chains for wetting. As some of the polymer chains
may also enter into the holes of the particles depending on the rheological (viscosity)
properties of the polymers, the so-called physical entrapment and physical crosslink
may also play an important role during reinforcement of elastomeric matrices. One of
the most important parameters for the performance of a composite material is the
degree of adhesion at the matrix filler interface.
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