Authors: L. Balzano, S. Rastogi and G. Peters
Affilation: Technical University Eindhoven, Netherlands
Pages: 820 - 823
Keywords: self-assembly, nucleating agent, gel, rheology, X-ray
Presence of additives in polymers plays an important role in physical and mechanical properties. For an example DMDBS is one of the frequently used additives in polypropylenes. The additive is used to achieve higher transparency a result of enhanced crystallization rate in its presence. In this paper we explore structural development of the polymer (isotactic polypropylene) in presence of the additive (DMDBS) under controlled flow conditions. Presence of less than 0.5 wt % of additive shows strong influence of flow in the crystallization of the polymer. Even in the melt state of the polymer, DMDBS tends to self assemble at the nanoscale forming a gel like network, as explored from rheological studies. The network tends to orient under defined flow conditions. Simultaneous time resolved rheological and X-ray studies demonstrate that oriented gel network can be retained for considerably long even well above melting temperature of the polymer. Strongly favorable molecular matching between the polymer and the additive favors the epitaxial nucleation on cooling. This offers a unique possibility to obtain highly anisotropic crystal morphology having implications on polymer processing. In this paper we will demonstrate implications of a nano event, which is strongly influenced by temperature, flow, additive concentration, on the macroscopic properties relevant for processing.
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