Abstract

The awareness for developing an eco-friendly industry based on green materials, sustainable technologies and optimum process with less environmental impact are a general societal consciousness, but it is still a considerable challenge to achieve. The biodegradable structural materials can contribute to reduce the CO2 emissions, the carbon footprint and increase the concept of recyclability for structural applications. In terms of performances, the natural fiber reinforced composite material could become in worthy alternative to E-Glass composite, wood reinforced materials and aluminum alloys because of their good ratio between mechanical properties, density and cost. However, the structural engineering applications are still very limited mainly because the lack of a robust manufacturing process. For that purpose, it has been developed an innovative mechanical extraction methodology based on the morphology of two species of bamboo, along with the optimization of the melting parameters to manufacture a fully biodegradable Bamboo-PLA composite. Furthermore, in order to define the future applications, the mechanical properties have been analyzed under different thermal cycling conditions.

Abstract

Nowadays, glass fiber reinforced polyester laminates are widely used in manufacturing small ship hulls by hand lay-up. The main drawbacks of the use of these composite materials are: the dependence of hydrocarbons on the synthesis of resins, the high energy cost to obtain glass fiber and the emission of volatile harmful compounds in the manufacturing process. In this work, the advantages of using flax fiber reinforced bioresins are analyzed. Tensile and flexural standard tests were performanced. After that, a small craft of less than 24 meters in length is designed in accordance with the international norm ISO 12215-5. The results indicate that despite the need for greater thickness, the total weight of the vessel is reduced by 12% using biocomposites. Besides, Finite Element Analysis (FEM) indicates that the structural design can be clearly optimizated. Finally, Life Cycle Assessment (LCA) reveals an environmental improvement of the boat made of biocomposite instead of glass fiber. However, this improvement is limited by land occupation and the high water footprint of flax fiber in its production process.

Abstract

In this work, new biocomposites were manufactured and mechanically tested. A resin from natural resources (SuperSap®) was reinforced by a bidirectional flax and oak wood laminates.

Normalized tensile and three-point bending tests were performed and it was observed that the oak wood laminates in the outer layers give a great aesthetic finish and the tensile stiffness is also increased a 2% compared to the flax reinforced biocomposite. Regarding the results of three-point bending, the oak laminates in the core provide a greater flexure breaking strength, which is a 10% higher than the flax reinforced biocomposite. SEM micrographs show both the accuracy of the infusion process and the good adhesion of the different natural fibres and bioresin.

Finite Element simulations (FEM) were carried out at different pressures generated by three wind velocities (V_wind= 3, 8 and 11m/s). Both tension and deformation results show that the structural integrity of the biocomposite wind blades is not compromised. Finally, the real tests in the wind tunnel have validated the use of the developed biomaterials in manufacturing blades for small wind turbines.

Abstract

This work is oriented towards the search of new materials friendly to the environment, for this the mechanical and thermal characterization of the natural fiber of Cumare (Astrocaryum chambira) was carried out by tensile and TGA tests, respectively. Subsequently, the biocomposite material was fabricated, using an artisan fabric made by the Tukano ethnic group of the Colombian Amazon, impregnated with bioepoxy resin using of the vacuum assisted resin transfer method (VARTM), obtaining in this way, specimens that were characterized by standards. The maximum tensile and flexural stress values ​​of the cumare / bioepoxy biocomposite were compared with other composite systems with natural fiber, yielding values ​​very similar to or higher than those reported by other authors. The values ​​obtained in the validated the simulation for an industrial application of an interior opening handle for the door in a vehicle using finite elements. As a significant contribution in the present investigation, the cumare Colombian fiber is presented as an ecological alternative of low cost for the reinforcement of materials bicompuestos with industrial applications in the automotive sector.

Abstract

The widespread use of glass fibre-reinforced composites in the marine industry is primarily attributed to their low cost, favourable mechanical properties, and high resistance to marine corrosion. However, their limited recyclability poses significant environmental concerns at end-of-life (EoL). Consequently, more sustainable alternatives such as biocomposites reinforced with natural fibres are being explored. This study presents a comparative Life Cycle Assessment (LCA) of the fore hatch of a small boat, currently manufactured by hand lay-up using glass fibre reinforced polyester glass fibre (GFRP), and a proposed alternative with flax fabric reinforced bio-epoxy (FFRB) produced by vacuum infusion. Initially, FFRB laminates were manufactured and mechanically characterised through three-point bending tests. Based on ISO 12215-5:2019 for small craft construction, the required laminate thicknesses for the FFRB hatch were determined, achieving a 14% weight reduction compared to the GFRP counterpart. Subsequently, a cradle-to-grave LCA was performed using OpenLCA software and the Ecoinvent v3.9.1 database. Results revealed that the FFRB hatch offers lower environmental impacts in fossil fuel depletion (ΔADP = –16%) and human toxicity (ΔHTP = –54%). However, terrestrial ecotoxicity (ΔTETP = +238%) increased due to pesticide and fertiliser use in flax cultivation. In conclusion, FFRB represents an environmentally sustainable alternative for marine component manufacturing, although further research is required to enhance its end-of-life performance.