Cellulose is the most abundant polymer on earth and can be found in plants or animals but is also produced by the Komagataeibacter strain of bacteria in the form of a wet reticulated nanofibre network called bacterial cellulose. With an estimated tensile modulus and strength of 114 GPa and 1.6-3 GPa respectively, cellulose nanofibres, represent a high potential green alternative to conventional polymer reinforcement such as glass fibres. The use of the hydrogen bonding ability of cellulose nanofibres to form strong dense fibrous networks (nanopapers) is essential to manufacture high fibre loading fractions (&gt;30 vol.-%) polymer composites capable of rivalling commercial plastic materials. Achieving impregnation of the nanopaper by the matrix is a critical step in utilising the single cellulose nanofiber tensile properties. In order to improve the network impregnation, we investigate in this study the use of low grammage bacterial cellulose nanopapers to produce BC-reinforced polylactide composites. Bacterial cellulose (BC) nanopaper-reinforced polylactide laminated composites containing 50 g m-2 of BC nanopapers were produced using 10, 5, 2 and 1 layer(s) of 5 g m-2, 10 g m-2, 25 g m-2 and 50 g m-2 BC nanopapers, respectively. The filtration of the 5 g m-2 nanopaper was found to be 3 times faster than for the 50 g m-2 and lead to networks with a high posority (78%). Tensile properties of the nanopapers were found to decrease with lower grammages resulting in the 5 g m-2 BC nanopapers possessing the lowest tensile modulus and strength, at 2.4 GPa and 30 MPa respectively. The composite containing 10 layers of 5 g m-2 BC nanopapers (vf= 38 vol.-%), with a tensile strength and modulus of 95 MPa and 11 GPa respectively, possessed tensile properties comparable to that of the composite containing 1 layer of 50 g m-2 BC nanopaper (vf= 52 vol.-%), with a tensile strength and modulus of 110 MPa and 12 GPa respectively. The better tensile properties of the thin ply composite than its nanopaper reinforcement could be due to the increased porosity of the nanopapers, as grammage was lowered, that lead to an impregnation enhancement. A higher PLA crystallinity, due to an increased contact area with nanocellulose fibres, was also found partially responsible. A comparison between the tensile moduli of the composites and predictions from the rule of mixture and the Cox-Krenchel model is also discussed in the presentation.

Thin ply bacterial cellulose-reinforced polylactide nanocomposites

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.