Composites reinforced with Guadua fibers: Physical and mechanical properties

•Surface treatments increases the crystallinity and roughness of the fibers.•Surface treatments reduces the absorption capacity of fibers.•Panels elaborated with unidirectional fibers and plasma treatment presented higher values of strength and stiffness. The need to mitigate the environmental impact produced by the use of conventional materials in the construction sector of industry has motivated research based on alternative composite materials reinforced with vegetable fibers. In this paper, the influence of the orientation of the fibers and the effect of their surface treatments on the physical and mechanical properties of panels constructed using non-conventional materials were analyzed. For the manufacture of the composites, bamboo fibers and castor oil resin were used. In order to evaluate the effect of the orientation of the fibers on the performance of the composite, two fiber typologies were employed: long, unidirectional fibers and randomly-distributed short fibers. To modify the surface of the fibers, two methods were applied: a cold plasma treatment and an alkaline treatment. The physical characterization was focused on the determination of the theoretical and experimental density, the effective absorption, and the percentage of swelling. The mechanical characterization focused on the determination of the tensile, compression, and flexural behavior. In order to evaluate the degradation of the material with the temperature, a thermogravimetric test was performed. The results obtained demonstrate the influence of the orientation and surface modifications of the fibers on the physical and mechanical behavior of non-conventional composites.