Polymerizable Choline- and Imidazolium-Based Ionic Liquids Reinforced with Bacterial Cellulose for 3D-Printing.

Michael A Smirnov,Michael A Smirnov,Alexandra L Nikolaeva,Veronika S Fedotova,Maria P Sokolova,Vladimir Yu Elokhovsky,Mikko Karttunen,Mikko Karttunen,Veronika S Fedotova

doi:10.3390/polym13183044

Michael A Smirnov, Michael A Smirnov + Show 7 more

Open Access

https://doi.org/10.3390/polym13183044

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Abstract

In this work, a novel approach is demonstrated for 3D-printing of bacterial cellulose (BC) reinforced UV-curable ion gels using two-component solvents based on 1-butyl-3-methylimidazolium chloride or choline chloride combined with acrylic acid. Preservation of cellulose’s crystalline and nanofibrous structure is demonstrated using wide-angle X-ray diffraction (WAXD) and atomic force microscopy (AFM). Rheological measurements reveal that cholinium-based systems, in comparison with imidazolium-based ones, are characterised with lower viscosity at low shear rates and improved stability against phase separation at high shear rates. Grafting of poly(acrylic acid) onto the surfaces of cellulose nanofibers during UV-induced polymerization of acrylic acid results in higher elongation at break for choline chloride-based compositions: 175% in comparison with 94% for imidazolium-based systems as well as enhanced mechanical properties in compression mode. As a result, cholinium-based BC ion gels containing acrylic acid can be considered as more suitable for 3D-printing of objects with improved mechanical properties due to increased dispersion stability and filler/matrix interaction.

Highlights

Manufacturing of products with complex shapes is a problem that has both practical and fundamental material-related challenges
Crystalline cellulose organized in nanofibrils can be produced by bacterial synthesis and is commonly referred to as bacterial cellulose (BC)
In order to fill this gap, we have studied two cases of polymerizable compositions for the preparation of cellulose nanofibers (CNF)-reinforced ion gels

Summary

Introduction

Manufacturing of products with complex shapes is a problem that has both practical and fundamental material-related challenges. The rise of 3D-printing based on biopolymerbased materials offers, a viable and versatile method for natural polymers [1,2,3,4]. Cellulose—the most abundant natural polymer—is a prospective candidate for the generation of sustainable and biocompatible materials. Its crystalline parts demonstrate extremely high mechanical properties [5], which makes cellulose nanomaterials prospective reinforcing fillers [6,7,8,9,10]. Crystalline cellulose organized in nanofibrils can be produced by bacterial synthesis and is commonly referred to as bacterial cellulose (BC). What complicates processing of cellulose is that its strong network of hydrogen bonds What complicates processing of cellulose is that its strong network of hydrogen bonds (hydrogen bonding in the context of cellulose in contact with membranes has been characterised e.g., in Refs. [15,16]) makes it insoluble in common solvents and non-meltable at temperatures lower than its decomposition temperature

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