Chemical interaction between epoxidized natural rubber and silica: Studies on cure characteristics and low-temperature dynamic mechanical properties

Epoxidized natural rubber (ENR)/Polypropylene (PP) thermoplastic vulcanizates were prepared by melt mixing method in an internal mixer. Influences of different mixing methods for incorporation of processing oil into the TPVs on tensile and dynamic mechanical properties of the TPVs and crystallinity of the PP were investigated. Results show that distribution of processing oil in the ENR/PP TPV is important due to the processing oil can promote and in the same time can interrupt an improvement in elastomeric properties of the TPV. Incorporation of processing oil into the ENR phase by preparation of oil extended ENR (the mixing method 1) before mixing with the PP was the better way to produce the TPV. It promoted the TPV with superior tensile and dynamic mechanical properties than the TPVs prepared from the mixing method 2 and 3 in which the processing oil was directly added into the PP phase. Furthermore, the TPV from the mixing method 1 had less effect of processing oil on the PP crystallization.

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Influence of Filler from a Renewable Resource and Silane Coupling Agent on the Properties of Epoxidized Natural Rubber Vulcanizates

Journal of Chemistry ◽

10.1155/2015/796459 ◽

2015 ◽

Vol 2015 ◽

pp. 1-15 ◽

Cited By ~ 20

Author(s):

Wiphawadee Pongdong ◽

Charoen Nakason ◽

Claudia Kummerlöwe ◽

Norbert Vennemann

Keyword(s):

Mechanical Properties ◽

Metal Oxide ◽

Natural Rubber ◽

Elevated Temperatures ◽

Polymer Network ◽

Renewable Resource ◽

Dynamic Mechanical Properties ◽

Epoxidized Natural Rubber ◽

Cure Characteristics ◽

Temperature Scanning

Rice husk ash (RHA) was used as a reinforcing filler in epoxidized natural rubber (ENR) with various loading levels (0, 10, 20, and 30 phr), and silica filled ENR was also studied for comparison. The effects of RHA content on cure characteristics, mechanical properties, dynamic mechanical properties, and thermoelastic behavior of the filled ENR composites were investigated. It was found that the incorporation of RHA significantly affected the cure characteristics and mechanical properties. That is, the incorporation of RHA caused faster curing reactions and increased Young’s modulus and tensile strength relative to the unfilled compound. This might be attributed to the metal oxide impurities in RHA that enhance the crosslinking reactions, thus increasing the crosslink density. Further improvements in the curing behavior and the mechanical properties of the filled composites were achieved byin situsilanization with bis(triethoxysilylpropyl) tetrasulfide (Si69). It was found that the rubber-filler interactions reinforced the composites. This was indicated by the decreased damping characteristic(tan ⁡δ)and the other changes in the mechanical properties. Furthermore, the ENR composites with Si69 had improved filler dispersion. Temperature scanning stress relaxation (TSSR) results suggest that the metal oxide impurities in RHA promote degradation of the polymer network at elevated temperatures.

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