Superpozice smykových toků plněných polymerních tavenin

Abstract

Superpozice ustálených a oscilačních smykových toků poskytuje důležité poznatky v charakterizaci kompozitních systémů. Experiment byl proveden na polymerních kompozitech s uhlíkovými vlákny. Superponovaný tok zvyšuje viskoelastické vlastnosti daných materiálů; zatímco u čisté polymerní matrice je průběh monotónní, se zvyšujícím se přídavkem pliva se stává komplikovanějším.

Superposed steady and oscillatory shear flow measurements provide non-conventional view on characterization of fibre filled systems. The purpose of this study was to investigate the flow properties of polymer melt compounded with carbon fibre (CF) under the parallel superposed steady and oscillatory shear flows. The effect of the steady shear on the viscoelastic properties as well as the effect of fibre content on the superposed flow properties were discussed. Overall, superposed flow conditions enhanced viscoelastic response (dynamic viscosity, storage modulus) of the filled systems. The critical angular frequency, where phase angle becomes 90° and storage modulus decreases sharply to zero, was found to be largely dependent on the volume fraction of fibre, regardless of the superposed shear rate. Whereas superposed flow properties of the pure melt changed monotonously, those of the composites showed peaks in corresponding dependencies, even if under simple shear flows they behaved in the similar manner as matrix.