Study of chemical and enzymatic functionalization of lignocellulosic natural fibers

Within the commercially available materials, composites are a class of hybrid

material constituted of at least two components. Used for structural and semi-
structural applications, glass-fibers composites are widely spread. Due to

environmental concerns regarding the final glass-fibers reinforced composites,
natural plant fibers have been identified as a potential ersatz. Natural fibers are
selected on the base of their intrinsic mechanical resistance, similar nay enhanced
than glass-fibers. Local fibers suitable for such application could be found all around
the world.
In Europe, natural fibers market is singularly different from the rest of the world.
Instead of being ruled by cotton cultivation and trade, flax and hemp represent the
main part of the fibers culture and market in Europe. Their physico-chemical
properties turn them suitable for use as reinforcement agent in plastic matrix.
To elaborate composite, many steps are required from fibers harvesting to the
obtaining of a final functional material. Each step includes multiple parameters to
control which affect the resulting composite mechanical properties. Different
parameters of the composite elaboration were evaluated to determine which affect
the most the final material mechanical properties. Constitutive biopolymers of the
fibers were found to play a crucial role in the improvement of the polypropylene and
thermoplastic starch reinforcement.
In heterogeneous materials such as composites, an optimal load transfer is
researched to fully exploit the properties of both initial components.
Interface quality between fibers and matrix determine this load transfer. In order to
improve the fibers-matrices compatibility, fibers treatments exist such as chemical
modification or enzymatic functionalization. The effects of these treatments were
evaluated at the fibers level and the resulting composite. This manuscript describes
and studies the design of functional natural fibers as plastic reinforcement agent.