화학공학소재연구정보센터
Polymer, Vol.35, No.18, 3958-3965, 1994
Thermoplastic Elastomers from Blends of Polyethylene and Ethylene-Propylene-Diene Rubber - Influence of Vulcanization Technique on Phase Morphology and Vulcanizate Properties
Comparative studies on the dynamic and static vulcanization of blends of polyethylene (PE) and ethylene-propylene-diene monomer rubber (EPDM) are reported. The studies were made using a PE/EPDM blend ratio range of 40/60 to 20/80, over which the occurrence of phase inversion was indicated from torque rheometric studies. The state and rate of sulfur cure were varied by use of different appropriate doses of (a) tetramethylthiuram disulfide-mercaptobenzthiazyl disulfide-sulfur (TMTD-MBTS-S) combination as a conventional curative and (b) TMTD-Si69-S combination as a silane curative system. Of the two curative systems, the conventional system imparted measurably higher cure rates. For a particular blend ratio and for a given crosslink density level established in each case, the tensile strength and elongation at break measured at 298 K were higher for vulcanizates obtained statically compared to those obtained dynamically, while the corresponding modulus values followed the opposite trend. High-temperature tensile properties (at 403 K) and hot elongation and hot set values (at 523 K) for the vulcanizates were also evaluated. The property differences for vulcanizates from static and dynamic curing have been explained in the light of differences in the morphology developed.