Influence of Carbon Black Properties on the Joule Heating Stimulated Shape-Memory Behavior of Filled Ethylene-1-Octene Copolymer

The shape-memory (SM) behavior of ethylene-1-octene copolymer (EOC) reinforced by carbon black (CB) was investigated. Two CB types, N110 and EC600, with different structure and specific surface area were used as conductive fillers. The mechanical tests showed that on addition of CB into EOC, modulus and strength increased significantly for both CB types but the elastic behavior stands on. The electrical resistivity decreases drastically with increasing CB content. The thermally stimulated SM recovery is deteriorated significantly because of the rigid CB network formed in EOC. With increasing temperature, the CB network gradually loses its rigidity, as the glassy polymer layers connecting the CB aggregates become softened. As a result, the samples with high CB content could recover nearly 100%. In this work, a sample preparation and a corresponding arrangement of experiment were introduced, which allows to quantify the Joule heating stimulated recovery behavior. EOC containing 17 wt% CB EC600 reaches a low resistivity of 8 Omega cm and shows good Joule heating stimulated SM recovery of up to 97% at a voltage of 15 V. POLYM. ENG. SCI., 51:500-508, 2011. (C) 2010 Society of Plastics Engineers