Highly porous and light-weight flax/PLA composites

International audienceLightweight, highly porous and mechanically strong flax/PLA composites were prepared using an original way of flax “fibrillation”. Flax fibres having the aspect ratio of around 100 and diameter of 20 μm were prepared and used as a matrix. It was impregnated with PLA dissolved in chloroform which was then evaporated. The density of composites varied from 0.1 to 0.2 g/cm3 and average porosity was around 90%. Physical and mechanical properties of neat flax matrix and flax/PLA composites were studied as a function of polymer loading and flax concentration. SEM analysis showed that flax fibres form a 3D random fibre network where PLA binds flax fibres at their intersections. Compression tests revealed a significant influence of PLA concentration on the mechanical properties of composites: the addition of 0.056 g/cm3 (34 wt%) of PLA resulted in an increase of compression modulus from 0.06 MPa for neat flax matrix to 1.6 MPa for composite, although composites remained flexible. The presence of PLA decreased composite moisture adsorption by approximately 40% as compared with neat flax matrix. Good relative mechanical properties, biocompatibility, high porosity and facile preparation method of these composites open up possibilities for biomedical applications