Ming-Tsong Leu

Reinforcement of dynamically vulcanized EPDM/PP elastomers using organoclay fillers

Abstract Dynamically vulcanized EPDM/PP (ethylene-propylene-diene/polypropylene) elastomers reinforced with various amounts of organoclay were prepared using octylphenol-formaldehyde resin and stannous chloride dehydrate as vulcanizing agents. The effects of organoclay on vulcanization characteristics, rheological behavior, morphology, thermal stability and thermomechanical properties were studied. Experimental results showed that organoclay affected neither the vulcanization process nor the degree of vulcanization chemically. X-ray analysis revealed that these organoclay-filled thermoplastic vulcanizates (TPVs) were intercalated. With respect to the mechanical properties, organoclay increased both the strength and degree of elongation of TPVs. The morphological observation of fractured surfaces suggested that organoclay acted as a nucleating agent in TPVs, improving their mechanical properties. However, adding organoclay reduced the thermal stability of TPVs by decomposing the swelling agents in the organoclay.

Effect of Complex Curatives on the Properties for Ethylene Propylene Diene Rubber/Polypropylene Blends

This study investigates the effects of different types of curatives at polypropylene (PP) and ethylene propylene diene monomer (EPDM) blend ratios (100 : 40 phr) in dynamically vulcanized products. The thermoplastic vulcanizates are prepared by batch melt mixing of PP with EPDM, using pheolic resin, dicumyl peroxide, hydrosilyation, and complex systems as curatives. Observed changes in curing characteristics and mechanical properties of blends have been correlated with phase morphology, as attested by scanning electron micrographs. On the basis of the obtained results, different curative systems control final vulcanizing characteristics, mechanical properties, morphology, intermolecular interaction, and thermal properties of EPDM/PP blends.