Universal Journal of Materials Science 6(4): 133-138, 2018 http://www.hrpub.org DOI: 10.13189/ujms.2018.060403 Synthesis of Polymeric Composites Reinforced with Unidirectional and Bidirectional Bamboo Fibers Milene Muniz Eloy da Costa * , Santino Loruan Silvestre de Melo, Enio Pontes de Deus Department of Metallurgical and Materials Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil Copyright©2018 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract Due to environmental problems and exhaustion related to materials provided from non-renewable sources, the development of recycling technologies using residue as raw material has grown increasingly. Polypropylene (PP), a thermoplastic polymer, despite be easily recycled, presents a decrease in their mechanical properties after reprocessing cycles. In order to solve this problem, reinforcements may be added, producing a composite with better properties. The choosing of the dispersed phase aimed to consider, especially, its mechanical properties. Moreover, it was also considered the orientations of the incorporated fibers at the composite mechanical strength. In this scenario, a composite material of polymer matrix from recycled PP reinforced unidirectionally and bidirectionally with bamboo fibers were prepared. The fibers were treated with modifiers in order to increase the adhesion between polymer/fiber. The results showed that the use of reinforcement improves the mechanical properties of the polymer. Also, the superficial treatments were effective, indicating that there was an increase of the compatibility between the materials. It can be also inferred that the orientation of the fibers has directly influence at the final properties of the composite. Keywords Recycled Polypropylene, Bamboo Fibers, Reinforcement Orientation, Polymeric Composites, Surface Modifiers 1. Introduction Polymers are formed by macromolecules constituted by the repetition of short chemical units called monomers [1]. Conventionally, polymers are prepared from petroleum fractions, non-renewable and not biodegradable source, contributing a lot for the residues generation. Therefore, researchers and industry have been seeking alternatives to minimize the impacts caused by improper and exaggerated disposal of these materials. Thus, the reuse and recycling are presented as management strategies of these residues, also involving the deployment of industrial ecology, which means that nothing is residue, but a raw material for a new product [2, 3]. In addition, other aspects motivate these processes, such as economy of energy (the manufacturing of recycled plastic saves about 70% of energy), of financial (reduction of expenses with cleaning and public health) and environmental (reduction with the recovery of impacted areas, such as rivers and lakes) [4]. According to surveys conducted in major Brazilian cities, the recycling of plastics remains slow due to the lack of selective waste collection associated with an efficient waste sorting. The main polymers found in these urban residues are high and low density polyethylene (HDPE and LDPE), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polypropylene (PP) [4, 5]. The PP is a polymer synthesized from propylene monomer. It is a colorless material with excellent mechanical properties related to its crystallinity. The atactic PP, with all methyl groups allocated irregularly along the chain, is the most used in the market [6, 7]. This polymer is a semi-rigid, translucent, with a good mechanical, electrical, thermal and chemical strength, etc. [6, 8]. Furthermore, because it is a thermoplastic, the PP has a great usability and can be formed easily, that is, a widely recyclable material. However, the recycling of polymers causes depletion of its mechanical properties because it increases the amount of defects. These did not significantly interfere with mechanical behavior until the maximum force was reached. From this point, where the propagation of cracks has a great influence on the deformation until the rupture, the defects were determinants in the deformation [8, 9]. This problem can be solved with the mixture of the virgin and recycled PP, which has yielded good results [9], or with the addition of reinforcements in polymer matrix. This method aims to increase the mechanical strength of materials, resulting in composite materials with wide applicability. There are numerous materials used as reinforcement of composites, among them the fibrous one deserve attention. The fibers are effective means for reinforce due to its low thickness, tending thus to provide fewer defects that may