Simultaneous electrical and rheological measurements on conductive polymer composites under elongation

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The renewal proposal concerns with simultaneous electrical and rheological measurements in elongation on melts of conductive polymer composites (CPC). These measurements were developed recently in the frame of the original research project. The electrical properties of conductive polymer composites are governed by the particle structures which are formed during the processing of the composite. Taking into account that the elongational flow is involved in many melt processing technologies, the knowledge and the understanding of particle structures behaviour under elongation in the molten state are crucial in production of CPC with balanced electrical and processing properties. The first aim of the project is to investigate the behaviour of conductive particle structures after elongation in relaxation and recovery mode. This study is important from the practical point of view, as the relaxation/recovery step occurs always after melt processing and, thus, influences the electrical conductivity of the final product. Moreover, the simultaneous electrical and rheological measurements can help in understanding of the origins of the effects observed in elongational rheology of filled polymer systems. Contrary to the rheological quantities integrating the effects of particle structures, polymer-particles interactions and polymer matrix, the electrical measurements reflect the changes in the particle structures only. Therefore, simultaneous elongational experiments allows one to decide to which extent are the flow-induced changes in particle structures responsible for the strain thinning behaviour, the flow restrictions in elongation or reduction of the elasticity induced by incorporation of the filler in the polymer matrix. The second aim of the project proposed is to perform systematic studies of the effects mentioned above with respect to filler concentration, temperature and conditions of elongation.