Interrelationships of morphology, thermal and mechanical properties in uncrosslinked and dynamically crosslinked PP/EOC and PP/EPDM blends

Abstract

Abstract. Thermoplastic vulcanizates (TPVs) based on polypropylene (PP) with ethylene octene copolymer (EOC) and ethylene propylene diene rubber (EPDM) have been developed by coagent assisted dicumyl peroxide crosslinking system. The study was pursued to explore the influence of two dissimilar polyolefin polymers (EOC and EPDM) having different molecular architectures on the state and mode of dispersion of the blend components and their effects with special reference to morphological, thermal and mechanical characteristics. The effects of dynamic crosslinking of the PP/EOC and PP/EPDM have been compared by varying the concentration of crosslinking agent and ratio of blend components. The results suggested that the uncrosslinked and dynamically crosslinked blends of PP/EOC exhibit superior mechanical properties over PP/EPDM blends. From the hystersis experiments it was found that PP/EOC blends also perform better fatigue properties over PP/EPDM based blends. It was demonstrated that, the origin of the improved mechanical properties of EOC based blends is due to the combined effect of the unique molecular architecture with the presence of smaller crystals and better interfacial interaction of EOC phase with PP as supported by the results of thermal and fatigue analyses.

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part B: influence of clay addition

“…The literature presents some works in which dynamic vulcanization is analyzed during processing into internal mixer [22,[37][38][39][40][41][42][43][44] , as performed on this work. In this particular case, the influence of a clay addition in the dynamic revulcanization reaction is analyzed.…”

Novel thermoplastic vulcanizates (TPVs) based on silicone rubber and polyamide exploring peroxide cross-linking

“…Further TPVs based on silicone rubber [16] and maleated ethylene propylene rubber (EPM) [17] was also developed for some special purpose. Babu and coworkers [18,19] explored a new TPV based on polypropylene (PP) and ethylene octene copolymer (EOC) blend system. EOC has gained special attention because of its unique molecular structure and also it provides better toughening characteristics than EPDM rubber [20,21].…”

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part A: influence of devulcanization process

“…Some researchers use this advantage to examine different phenomena such as dynamic vulcanization [21][22][23][24][25][26][27][28][29] , as performed in this work. During the mixing, just after the addition of the matrix phase and as soon as the torque measured by the equipment was stabilized, GTR (containing or not vulcanization additives) was added into the mixer, what permitted the analysis of the dynamic revulcanization behavior of the blends, which is shown in Table 3.…”

“…G' is influenced also by morphology of the blends [28,37] . The morphology refinement and compatibility tend to increase the G' values.…”