Impact of wood fibers on the mechanical performance of biocomposite materials

Abstract: Plastics are amazing materials with outstanding properties that make them very useful and cheap for a wide range of uses. However, their pollution to the environment has become one of the main problems to solve in this century. In this Master Thesis biocomposites from Biofiber Tech are studied. This material is a composite material formed by treated wood fibers and a polymeric matrix. The influence of the fibers in the matrix on the material properties is defined by many factors such as their orientation, distribution and adhesion capabilities with the matrix. To study different surface treatments that Biofiber Tech. has developed, Lund University received two different shipments of samples. On the first one, a microstructure inspection was performed with X-ray tomography and three different phases were characterized apart from the matrix: fibers, voids and fiber aggregates. The volume fraction, spatial and size distribution and orientation of these phases were quantified and related to the material structure and properties. For the second shipment of samples received, the study was focused more on the fracture mechanisms by carrying out premortem and post-mortem X-ray tomographies on tensile tested samples, observing the fractures in relation tu the structure of the material and distinguishing if the failure was caused by matrix, fiber or adhesive fracture.