Methods of surface treatment and its effect on the physical and mechanical properties of guadua fibers

Abstract

 The use of vegetable fibers as reinforcement of polymeric composites for application in civil engineering requires the implementation of surface modification methods. In this paper the evaluation of the effect of the surface modification on the properties of fibers extracted from the top of Guadua bamboo culm is presented. The fibers were obtained by means of a mechanical crushing process. Surface modification was carried out using two treatment methods: alkaline and plasma treatment. To observe the chemical composition of the fibers and their morphology, images were obtained by means of scanning electron microscopy (SEM). The roughness of the untreated fibers was determined by atomic force microscopy (AFM). The crystallinity index was determined by X-ray diffraction (XRD). The mechanical characterization focused on tensile tests. The results of physical and mechanical characterization allow to verify that when carrying out a superficial treatment it is possible to partially remove the lignin, the hemicellulose and other impurities, which contributes to increase the strength and the roughness of the fibers promoting a better adherence with the resins usually used in the elaboration of composite materials. Fibers treated by plasma showed an increase on the strength and their stiffness values. Results show that by using of this type of treatment is an increase nearest to 25% on the tensile strength of fibers, it is possible.