Relations between microstructural development and rheological properties in polymer nanocomposites
|Authors:||Mahi Hassanabadi, Hojjat|
|Abstract:||The main objective of this thesis is to understand the relations between microstructure and rheological properties of polymer nano-composites based on ethylene vinyl acetate (EVA) copolymer. The first part of the study is related to EVA-nano crystalline cellulose (NCC) composites. As a first step, determination of the unknown structure of the samples using rheological methods was investigated. By analyzing the properties obtained under shear and extensional deformations, the mechanisms leading to polymer reinforcement were investigated in details. In the second part, nano-composites containing isometric (CaCO3) and anisometric (clay) particles were used. The focus here was to determine the effect of structural variables such as polymer-particle and particle-particle interactions, state of dispersion, and in particular particle shape on the final properties of these nano-composites. The mechanisms involving these parameters were investigated through rheological properties and discussed with respect to experimental data. Predictions via the molecular stress function (MSF) model are also presented. It was found that higher particle anisomety led to greater polymer-particle and particle-particle interactions. Therefore, the effect of clay was much higher than CaCO3 on almost all the rheological parameters studied. But, lower predictability was found around the percolation concentration. Consequently, while a model based on chain dynamics could predict the behavior below percolation, such model failed to predict the response at higher concentrations. For percolated systems, models based on fractal networks, which include particle-particle interactions, were used.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||19 April 2018|
|Collection:||Thèses et mémoires|
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