Bacterial cellulose (BC) is an ultrapure form of cellulose nanofibres produced by the fermentation of low molecular weight sugars using cellulose-producing bacteria of the genus Acetobacter. BC is produced in the form of wet pellicle (a thick biofilm) as a continuous nanofibre network with high specific surface area and outstanding mechanical performance. Numerous researchers have produced BC-reinforced polymer composites in order to exploit the mechanical properties of the BC networks. However, previous research has been focused on the manufacturing of thin composite laminates with thicknesses of only ~200 μm, therefore limiting the engineering applications of these composites. Bacterial Cellulose (BC) pellicle has been used to reinforce polymethylmethacrylate (PMMA) to prepare 3 mm thick optically transparent composites. In this work, three novel composite designs were developed: (i) Composites with uniformly dispersed BC throughout PMMA; (ii) sandwich structured construction consisting of BC pellicle-reinforced PMMA sandwiched between two neat PMMA sheets; (iii) hornified and dried BC pellicle-reinforced PMMA composites. The aim of this work was to elucidate the influence of the reinforcement architecture on the impact strength and optical and mechanical properties of the composites. BC has proven to be an excellent stiffening agent by increasing the Young’s modulus up to 4.5 GPa with a loading fraction of only 1 vol.-% compared to a Young’s modulus of 3.3 GPa for neat PMMA. It has been found that the addition of BC to PMMA leads to matrix embrittlement but this can be mitigated by reducing the BC nanofiber-PMMA interface. The best performing composite design was reinforced with hornified dried BC pellicle, whereby the impact strength was 20% higher than neat PMMA, without sacrificing optical clarity.

Effect of the reinforcement architecture on the optical and mechanical properties of bacterial cellulose composites

2019 Spring National Meeting

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