Polymer composites are fast becoming a material in the manufacturing of automotive interior and exterior parts such as facias and dashboard components. Production of rigid structural foams are ideal because they reduce the overall weight as well as reduce the amount of material used to manufacture the part. Polymer-clay nanocomposites are a classification of materials containing a blend of polymer and a small weight percentage of nanoclay. These materials are currently of interest to automotive part manufacturers because they are known to deliver improved mechanical properties and increase foamability of a polymer. The current study investigates the changes in material properties and the foamability of a thermoplastic polyolefin (TPO)-clay nanocomposite as the degree of intercalation was varied. The TPO-clay nanocomposite was produced by melt blending TPO, nanoclay and maleic anhydride grafted polypropylene (MAHgPP) in a co-rotating twin screw extruder. The material was subjected to a multi-pass process to vary the degree of intercalation. Degree of intercalation was tracked by rheology, XRD and TEM micrographs. Part density, cell density and flexural modulus measurements were performed on foamed and non-foamed injection molded bars to observe changes in the foamability of the material. Material was also processed without clay and analyzed in the same manner. Through TEM and XRD analysis it was found that the degree of intercalation and delamination was varied with increasing number of passes. Rheological measurements showed that the TPO-clay nanocomposite underwent (beta)-scission and intercalation simultaneously. The changes in intercalation had a positive effect on the foamability of the TPO-clay nanocomposite. As well, the TPO-clay nanocomposite experienced an increase in flexural properties for both unfoamed and foamed parts compared to the TPO-PPgMAH blend; TPO-clay nanocomposite experienced a 44% and 23% increase in the flexural modulus for unfoamed and foamed parts respectively. Data also showed that there was a limit to the number of times the TPO-clay nanocomposite can be recycled before the foamability of the material begins to decrease, which was attributed to material degradation. / Thesis / Master of Applied Science (MASc)

L’amélioration des performances des dispositifs photovoltaïques organiques passe par le contrôle de la morphologie de leurs couches actives. Nous cherchons à préparer une hétérojonction volumique donneur-accepteur nanostructurée en utilisant la nucléation hétérogène des poly(3-alkylthiophène)s (P3AT) donneurs sur des fibres d'organogélateurs accepteurs à base de pérylène bisimide (PBI).La première partie de ce travail présente la synthèse de trois dérivés PBI symétriquement N-substitués par des dendrons portant des groupes amides avec des chaînes latérales linéaires (PBI-C8) et ramifiées (PBI-C10) ou par une chaîne alkyle linéaire (PBI-L18). Leur étude physicochimique comparée met en évidence le rôle des liaisons H et de la substitution des chaînes latérales dans l’auto-assemblage.La seconde partie détaille les conditions d’obtention, la structure et les propriétés de deux polymorphes du PBI-C10 générés par la réorganisation des liaisons H.Finalement nous donnons une preuve de concept de l’obtention d’une hétérojonction donneur-accepteur par la nucléation des fibrilles de P3BT sur des rubans de PBI-C8 auto-assemblés. / Improving the performances of organic photovoltaic devices requires morphology control of the active layers. We seek to prepare highly nanostructured donor-acceptor bulk heterojunctions using the nucleation of semi-conducting donor polymers e.g. poly(3-alkylthiophene)s (P3AT) on self-assembled ribbons of perylene bisimide organogelators.The first part of this work concerns the synthesis of three PBI compounds symmetrically N-substituted by dendrons bearing amide groups and having linear (PBI-C8) and branched (PBI-C10) side-chains or a linear alkyl chain (PBI-L18). Their compared physicochemical study points to the role of H bonds and of side-chains substitution in the self-assembly process.The second part develops to a large extent the structure and the properties of two polymorphs of PBI-C10 generated by H bond reorganization.Finally, a proof of concept is given for the elaboration of donor-acceptor heterojunctions in solution by nucleating P3BT fibrils on self-assembled ribbons of PBI-C8.