Factors for selection of lignocellulosic fibers for use in structural composites

The success of a composite in its prospective application is measured by achieving an optimal matching between the matrix and the reinforcement, leading to a strong interface and a uniform impregnation of the highest possible content of fibers using the most suitable composite manufacturing process. When both fibers and matrix are synthetic, their properties can be controlled in most operational environments and possibly improved through judicious modification of their production processes. In contrast, when fibers are extracted from plants or derived as residues from an agrifood economic system, the fiber selection or optimization can be quite vague and ineffective. In the best case, it is possible to obtain “good enough” fibers, which may not be adapted to serve in engineering structures as self-supporting components. As a consequence, a thorough control of factors influencing the performance of plant fiber composite (PFC) characteristics is needed for PFCs to compete with their synthetic counterparts. This requirement has become increasingly crucial for the growing availability of biomass to be possibly used as a secondary raw material in structurally sound materials. A general framework for the many factors involved in reaching this goal is presented and described. The increasingly prevalent use of agricultural waste is also considered.