Mechanical properties and morphology of low density polyethylene/ polydimethylsiloxane immiscible blends: Modeling and influence of curing agent

Abstract

The tensile behavior of low density polyethylene/polydimethylsiloxane immiscible blends was investigated with respect to morphological variation of the blends. Experimental data of elastic modulus was compared with theoretical predictions of parallel model (mixing rule), as the upper bound of modulus, HalpinTsai model, and a two-parameter equivalent mechanical model proposed by Kolarik, which takes into account the continuity of minor phase. As the predictions of these models were not in good quantitative agreement with experiment, some modifications were made to the Kolarik model. Furthermore, a new approach for determining equivalent mechanical model parameters was proposed based on the calculation of phase continuity parameters as a function of composition. Using this approach, the values predicted for elastic modulus were found to be in good agreement with the experimental data. Moreover, the influence of a peroxide curing agent on the tensile properties of the blends was studied. The improvement of the tensile properties of the blends could have resulted from two contributions: the effect of curing reaction on the tensile properties of constituents and the better interfacial adhesion, because of possible interfacial reaction, as indicated by morphological observation.