Epoxy and Bio-Based Epoxy Carbon Fiber Twill Composites: Comparison of the Quasi-Static Properties

Abstract

In recent years, interest in sustainability has significantly increased in many industrial sectors. Sustainability can be achieved with both lightweight design and eco-friendly manufacturing processes. For example, concerns on the use of thermoset composite materials, with a lightweight design and a high specific strength, have arisen, since thermoset resins are not fully recyclable and are mainly petrol based. A possible solution to this issue is the replacement of the thermoset matrix with a recyclable or renewable matrix, such as bio-based resin. However, the mechanical properties of composites made with bio-based resin should be carefully experimentally assessed to guarantee a safe design and the structural integrity of the components. In this work, the quasi-static mechanical properties of composite specimens (eight layers of carbon fiber fabric) made with commercially available epoxy and a bio-based epoxy resins (31% bio content) are compared. Tensile tests on the investigated resins and tensile, compression, shear and flexural tests have been carried out on composite laminates manufactured with the two investigated resins. A finite element model has been calibrated in the LS-Dyna environment using the experimentally assessed mechanical properties. The experimental results have proven that the two composites showed similar quasi-static properties, proving that bio-based composite materials can be reliably employed as a substitute for epoxy resins without affecting the structural integrity of the component but lowering their carbon footprint.

Experimental Global Warming Potential-Weighted Specific Stiffness Comparison among Different Natural and Synthetic Fibers in a Composite Component Manufactured by Tailored Fiber Placement

“…Furthermore, no significant difference was observable between the mechanical behavior with respect to the two different epoxies, with similar results to Ref. [ 17 ], now considering a composite part.…”

“…As suggested by Mindermann et al [ 7 ], it is worth noticing that the resin system plays a significant role in the composite ecological performance, mainly when natural fibers are taken into account. Niutta et al [ 17 ] have compared quasi-static mechanical properties of petroleum- and bio-based epoxy resins and found no significant difference between them, apart from the GWP, which gives the designer the freedom to choose a bio-based epoxy system not only for ecological but also for technical reasons. La Rosa et al [ 11 ] have introduced an LCA comparison study between a bio-based polymer composite and a conventional glass/epoxy one.…”

Static and Impact Properties of Flax-Reinforced Polymers Prepared with Conventional Epoxy and Sustainable Resins

“…The curves show also that the strains at failure for composites prepared with IB2 resin and ELIUM resin are larger compared to the composite prepared with the conventional epoxy resin. This behavior was also observed by Boursier et al [ 38 ] and Iadarola et al [ 13 ], who showed that the resins that have a higher bio content exhibit a larger deformation to failure both for flexural and tensile tests. Flexural tests conducted on composite laminates prepared with flax fibers also showed that the strain to failure increases for both composites prepared with IB2 and Elium resins.…”

“…While the mechanical properties of bio-based resins appear promising, further research is necessary to compare them with commonly used epoxy resins in composite materials, ensuring safe design and structural integrity. Moreover, the suitability of these resins for vacuum infusion processes should be investigated due to potential viscosity issues [ 13 , 38 ]. Mechanical characterization of bio-based composite laminates is of utmost interest to universities and industries as it represents a promising approach for reducing the carbon footprint while employing existing production technologies.…”

Use of Bio-Epoxies and Their Effect on the Performance of Polymer Composites: A Critical Review

“…Among edible oils, options such as soybean [ 56 , 57 , 58 , 59 , 60 ], linseed [ 59 , 61 , 62 , 63 ] and hemp [ 60 , 64 , 65 ], stand out as potential sources for developing environmentally sustainable epoxy systems, as extensively analyzed in the comprehensive overview by Mustapha et al [ 66 ]. From triglyceride vegetable oils, such as coconut, soybean or palm oil, it is possible to obtain the glycerol , which is also commercially used to produce commercial resins [ 67 , 68 , 69 ] and proposed in the literature for the synthesis of new epoxy systems [ 38 , 70 , 71 ]. Furthermore, exploration into the integration of non-edible oils such as castor [ 72 , 73 ], karanja [ 37 ], and canola [ 74 ].…”