pps proceeding - Abstract Preview
pps proceeding
Symposium: S11 - Elastomers and Thermoplastic Elastomers
Poster Presentation
 
 

Influence of the Different Components in a TPV PP/EPDM Based with Low Hardenss

Gheller Jordao Jr. (1)*, Jacobi Marly Maldaner (2)

(1) UFRGS - SENAI CETEPO - Rio Grande do Sul - Brazil, (2) UFRGS - Rio Grande do Sul - Brazil

This study presents the properties of low hardness TPV’s based on polypropylene/ethylene propylene diene rubber (PP/EPDM) blends, in a ratio of 40/60, with 40phr of paraffinic oil. The TPV`s were obtained in an internal mixer with dicumyl peroxide (DCP) or phenolic resin as the crosslinking agents, and triallyl cyanurate (TAC) as the co-agent. The processing behavior, morphology, swelling behavior, hardness, tensile strength, compression set, abrasion resistance and dynamical mechanical properties were evaluated. In the Study I the crosslinking effects of DCP and phenolic resin were evaluated in an EPDM compound. From the rheometric curves was possible to conclude that 4phr de DCP and 5phr the phenolic resin are the appropriate quantities of these curing agents. When comparing the mechanical properties of these two compounds, the EPDM cured with DCP presented better performance. In the Study II the influence of PP crystallinity and the ethylene content in EPDM were evaluated in different TPV`s. The hardness and tensile strength are increased with increasing of the PP cristallinity.. At the same time, lower hardness TPV’s were obtained with EPDM with lower cristalinitty, that means, lower ethylene content. In the Study III the nature and the amount of the curing agents were evaluated. The phenolic resin, in the quantity of 5phr, resulted in a TPV with the best balance of properties. In the Study IV, silica, paraffinic oil as plasticizer, co-agent and protective system effects were investigated. The silica with higher surface area results in a TPV with properties considerably better. The increment in the plasticizer content decreases the hardness and tensile strength of the TPV. And at last, the protective system was effective when the TPV`s were exposed to heat aging.