Poly(high internal phase emulsion)s (poly(HIPE)s) are porous materials that are made <i>via</i> emulsion templating. Due to facile control of the pore size, their high porosity and surface area, these materials have attracted great attention in different applications such as absorbent materials, separation processes, reaction supports, tissue engineering scaffolds, and so on. While high porosity is one the most important characteristics of the poly(HIPE)s, it comes with the cost of diminished mechanical properties. Cellulose nanocrystals (CNCs) are renewable one-dimensional nanofillers with high crystallinity, outstanding Young’s modulus, surface active properties and biocompatibility which makes them ideal candidates to tune the poly(HIPE)s properties. In this research, the effect of introducing different hydrophobically modified CNCs to the continuous oil phase of the HIPE on the morphology and mechanical properties of poly(HIPE)s have been investigated. CNCs were extracted from Miscanthus x Giganteus (MxG-CNC) and their surfaces were modified with acetic anhydride (A-CNC), butyric anhydride (BA-CNC) and hexyl isocyanate (CNC-U-C6). Poly(HIPE) was synthesized <i>via</i> polymerization of a water-in-oil HIPE. As part of the preparation of the oil phase for the HIPE, functionalized CNCs at different weight fractions were dispersed into a mixture of acrylate monomer by ultrasonication to achieve a stable suspension. While incorporation of 1wt.% CNC-U-C6 did not show any significant change in poly(HIPE) morphology and any improvements in the mechanical properties (under the processing conditions used for this study), incorporation of different amounts of A-CNC and BA-CNC resulted in changes in morphology and the enhancement the compression modulus of wet poly(HIPE) nanocomposites. In some cases, the increase in the modulus was more than one order of magnitude at very low CNC loading level. The observed results were analyzed through consideration of the changes in the viscosity of the oil phase and the interfacial properties of the phases in the presence of the modified CNCs.

Morphology and mechanical properties of poly(HIPE) nanocomposites containing cellulose nanocrystals

254th National Meeting (2017)

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