Non-isothermal elongational flow of polymer nanocomposites

Abstract

The elongational flow is a very important flow involved in important processing operations, like spinning, film blowing, etc. In these processing operations, the molten polymer is subject to the elongational flow and at the same time is cooled (non-isothermal elongational flow). The response to the non-isothermal elongational flow of the melt is then the critical parameter to process the polymer in these processing operations. MS (melt strength) and BSR (breaking stretching ratio) are to two values measured during the non-isothermal flow and depend mainly on the molecular structure of the polymer. In biphasic systems, the adhesion and the shape of the dispersed particles play a very important role in determining the behaviour of the melt under this flow. Polymer nanocomposites are biphasic systems where the rigid dispersed particles are of nanometric size and this size and the adhesion with the matrix are of relevant importance when these systems are subjected to the non-isothermal elongational flow. In this communication, the non-isothermal elongational flow behaviour of some polymer nanocomposites systems is reported and the effects of the elongational flow on the morphology of polymer nanocomposites are described. The change of the morphology of some of these systems (organoclay modified and graphene nanocomposites) subjected to elongational flow is somehow similar to that already reported for polymer blends. In particular, reduction of the dimensions, exfoliation and alignment along the flow direction have been observed.