In the context of sustainable materials, bacterial cellulose (BC) is often regarded as a prime candidate as nano-reinforcement for the production of renewable polymer nanocomposites. However, the mechanical performance of most BC-reinforced polymer nanocomposites is often inferior than commercially available polylactide (PLLA). Approximately 80% of the reported nanocomposites performed worse or only equally well than PLLA. One major reason for this is the loading fraction of nanocellulose (vf) within the composites. In order to achieve or exceed the mechanical performance of PLLA, vf > 30 vol.-% is necessary. This poses a challenge in the manufacturing of the nanocomposites, as conventional polymer extrusion methods cannot be used. Researchers often have to either limit the choice of polymers to water-soluble polymers, using solvent exchange methods if non-water soluble polymers were to be used and for the case of BC, culturing BC in the presence of a polymer to produce high vf nanocomposites. These extra steps involved will no doubt lead to poor cost-performance ratio of the resulting nanocomposites. Therefore in this work, we apply the forgotten manufacturing concept of paper-based laminate (i.e: 'papreg') to BC nanopaper, producing BC nanopaper-reinforced PLLA, herein known as 'nano-papreg', with improved cost-performance ratio. We demonstrate that high performance nano-papreg containing 65 vol.-% of BC with tensile modulus and strength of 6.9 � 0.5 GPa and 125 � 10 MPa, respectively, can be fabricated without the use of laborious solvent exchange method or the use of water-soluble monomers. In addition to this, we also show that the tensile properties of nano-papreg are predominantly governed by the mechanical performance of BC nanopaper instead of the individual BC nanofibres due to difficulties impregnating the dense nanofibrous BC network. Micromechanical modelling of these BC-reinforced PLLA nanocomposites will also be discussed.

Making the most out of bacterial cellulose: Sustainable thermoplastic �nano-PaPreg�

248th National Meeting (2014)

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