This work deals with the manufacture and mechanical characterization of natural-fiber-reinforced biobased epoxy resins. Biolaminates are attractive to various industries because they are low-density, biodegradable, and lightweight materials. Natural fibers such as Ixtle, Henequen, and Jute were used as reinforcing fabrics for two biobased epoxy resins from Sicomin®. The manufacture of the biolaminates was carried out through the vacuum-assisted resin infusion process. The mechanical characterization revealed the Jute biolaminates present the highest stiffness and strength, whereas the Henequen biolaminates show high strain values. The rigid and semirigid biolaminates obtained in this work could drive new applications targeting industries that require lightweight and low-cost sustainable composites.

The manufacturing process of the aircraft cabin interior panels is expensive and time-consuming, and the resulting panel requires rework due to damages that occurred during their fabrication. The aircraft interior panels must meet structural requirements; hence sandwich composites of a honeycomb core covered with two layers of pre-impregnated fiberglass skin are used. Flat sandwich composites are transformed into panels with complex shapes or geometries using the compression molding process, leading to advanced manufacturing challenges. Some aircraft interior panels are required for non-structural applications; hence sandwich composites can be substituted by cheaper alternative materials and transformed using disruptive manufacturing techniques. This paper evaluates the feasibility of replacing the honeycomb and fiberglass skin layers core with rigid polyurethane foams and thermoplastic polymers. The results show that the structural composites have higher mechanical performances than the proposed sandwich composites, but they are compatible with non-structural applications. Sandwich composite fabrication using the vacuum forming process is feasible for developing non-structural panels. This manufacturing technique is fast, easy, economical, and ecological as it uses recyclable materials. The vacuum forming also covers the entire panel, thus eliminating tapestries, paints, or finishes to the aircraft interior panels. The conclusion of the article describes the focus of future research.

Sandwich composites are widely used in the manufacture of aircraft cabin interior panels for commercial aircraft, mainly due to the light weight of the composites and their high strength-to-weight ratio. Panels are used for floors, ceilings, kitchen walls, cabinets, seats, and cabin dividers. The honeycomb core of the panels is a very light structure that provides high rigidity, which is considerably increased with fiberglass face sheets. The panels are manufactured using the compression molding process, where the honeycomb core is crushed up to the desired thickness. The crushed core breaks fiberglass face sheets and causes other damage, so the panel must be reworked. Some damage is associated with excessive build-up of resin in localized areas, incomplete curing of the pre-impregnated fiberglass during the manufacturing process, and excessive temperature or residence time during the compression molding. This work evaluates the feasibility of using rigid polyurethane foams as a substitute for the honeycomb core. The thermal and viscoelastic behavior of the cured prepreg fiberglass under different manufacturing conditions is studied. The first part of this work presents the influence of the manufacturing parameters and the feasibility of using rigid foams in manufacturing flat panels oriented to non-structural applications. The conclusion of the article describes the focus of future research.

Spray coating and vacuum-assisted resin infusion processes were implemented in this work to develop multifunctional biocomposite laminates. The biocomposites were fabricated using a bio-based epoxy resin reinforced with natural sisal fibers coated with graphene nanoplatelets (GNPs). A systematic characterization of material properties was performed to evaluate the mechanical, thermomechanical, electrical, and piezoresistive behavior of biocomposites with different GNPs contents (0, 1, 4, 6, and 8 wt.%). The mechanical tests revealed that adding GNPs to biocomposites has a slight positive effect on their flexural properties compared to the neat biocomposites (without GNPs). The electrical and thermomechanical tests showed that the electrical conductivity and glass transition temperature of biocomposites containing GNPs were enhanced significantly, achieving average values of 5.19 x 10-4 S/m and 63.29°C (26%), respectively. Regarding electromechanical tests, the biocomposites with 8 wt.% GNPs exhibited an excellent piezoresistive behavior under monotonic loading conditions, achieving a gage factor (strain sensitivity) of 3.56. Bending tests with cyclic loading were also performed, and cyclic reproducibility of the piezoresistive response of the biocomposites after 10 cycles was demonstrated, evidencing that the incorporation of GNPs onto sisal fibers by spray-coating produces an effective formation of conductive networks into biocomposites suitable for sensing applications.