Basalt Fiber Hybridization Effects on High-Performance Sisal-Reinforced Biocomposites

Abstract

The increasing attention given to environmental protection, largely through specific regulations on environmental impact and the recycling of materials, has led to a considerable interest of researchers in biocomposites, materials consisting of bio-based or green polymer matrixes reinforced by natural fibers. Among the various reinforcing natural fibers, sisal fibers are particularly promising for their good mechanical properties, low specific weight and wide availability on the current market. As proven in literature by various authors, the hybridization of biocomposites by synthetical fibers or different natural fibers can lead to an interesting improvement of the mechanical properties or, in turn, of the strength against environmental agents. Consequently, this can lead to a significant enlargement of their practical applications, in particular from quite common non-structural applications (dashboards, fillings, soundproofing, etc.) towards semi-structural (panels, etc.) and structural applications (structural elements of civil construction and/or machine components). Hybridizations with natural fibers or with ecofriendly basalt fibers are the most interesting ones, since they permit the improvement of the biocomposite’s performance without an appreciable increment on environmental impact, as occurs instead for synthetic fiber hybridizations that are also widely proposed in the literature. In order to further increase the mechanical performance and, above all, to reduce the aging effects on high-performance sisal-reinforced biocomposites due to environmental agents, the hybridization of such biocomposites with basalt fibers are studied with tensile, compression and delamination tests performed by varying the exposition to environmental agents. In brief, the experimental analysis has shown that hybridization can lead to further enhancements of mechanical performance (strength and stiffness) that increase with basalt volume fraction and can lead to appreciable reductions in the aging effects on mechanical performance by simple hybridization of the surface laminae. Therefore, such a hybridization can be advantageously used in all practical outdoor applications in which high-performance sisal biocomposites can be exposed to significant environmental agents (temperature, humidity, UV).

Environmental aging effects on high-performance biocomposites reinforced by sisal fibers

“…The high performance biocomposites considered, are constituted by a green epoxy resin (partial biobased epoxy) produced by the American Entropy Resin Inc. (San Antonio, CA, USA), called SUPERSAP CNR, with IHN type hardener. As widely shown in previous studies [18][19][20][21][22][23][24][25] carried out by the same authors, this matrix exhibits an almost linear elastic behaviour, with the following main characteristics: density ρm = 1.05 g/cm 3 , tensile strength σm,R = 60 MPa, Young's modulus Em = 2.5 GPa, and tensile stress strain εm,R = 2.5%.…”

“…In order to give a further contribution to the knowledge of the effects of the environmental aging on biocomposites, this work, intends to investigate the influence of environmental aging on the mechanical properties of highperformance biocomposites consisting of a "green epoxy" matrix reinforced with sisal fibers. These biocomposites have already been developed by the same authors [18,19,[28][29][30][31][20][21][22][23][24][25][26][27]by means of preliminary manual packaging of unidirectional "stitched" fabrics, successive hand lay-up of the laminate, and subsequent compression molding process. As widely demonstrated in [19][20][21]23], .such biocomposites can be used advantageously to substitute metals and synthetical fiber composites in many practical application.…”

Developments and Industrial Applications of Basalt Fibre Reinforced Composite Materials

“…The experimental results demonstrated superior high impact energy and peak load of hybrid flax/basalt composites as compared to plain flax/vinylester ones demonstrating the hybridization technique as a promising strategy to improve toughness properties of natural fibre reinforced composites [100]. Zuccarello et al [101] studied the influence on mechanical performance and ageing characteristics of sisal-reinforced bio composites following hybridization with basalt fibres. The experimental analysis revealed improvement in mechanical performance and significant reduction in ageing effects on the mechanical properties of hybrid sisal/basalt fibre-reinforced bio composites with increase in basalt fibre volume fraction in the bio composite [101].…”

“…Zuccarello et al [101] studied the influence on mechanical performance and ageing characteristics of sisal-reinforced bio composites following hybridization with basalt fibres. The experimental analysis revealed improvement in mechanical performance and significant reduction in ageing effects on the mechanical properties of hybrid sisal/basalt fibre-reinforced bio composites with increase in basalt fibre volume fraction in the bio composite [101]. Mechanical performance of hybrid bast/basalt fibre reinforced polymer composites was investigated by Saleem et al [102], where addition of basalt fibres improved mechanical properties and energy absorption capacity of the composite which is a key requirement in the automotive sector.…”