Enzymatic pretreatment of seed flax- and polylactide-commingled nonwovens for composite processing

Commingled composites of polylactide (PLA) and seed flax fibers were prepared by carding and needle pressing of PLA and flax fibers to nonwoven mats followed by compression molding. The nonwoven mats were treated using two different types of cellulolytic enzymes, namely cellobiohydrolases and endoglucanases. Both the enzymes changed the properties of the seed flax fibers surface. The resulting composites were studied using scanning electron microscopy, mechanical testing and thermal analysis. The effects of these modifications were minor on the thermal and mechanical properties measured. However, in the scanning electron micrographs, a difference in the fiber pull-out behavior of the untreated and treated fibers was observed. Treated seed flax fibers showed an improvement in adhesion with PLA.