Property enhancement of kenaf fiber composites by means of vacuum-assisted resin transfer molding (VARTM)

Abstract

This work was aimed at applying vacuumassisted resin transfer molding (VARTM) technique to reinforced polymer molding products made of vegetable fibers. Kenaf (Hibiscus cannabinus L. Malvaceae) bast fibers were preformed into mat by means of a cold press. The unsaturated polyester resin was infused into the preforms at a vacuum pressure of 1.3-1.6 kPa. The examination of the mechanical properties and microstructure of the prepared composites indicated that the modulus of elasticity (MOE), modulus of rapture (MOR), and tensile strength (TS) of the VARTM composites were increased by 65.5%, 30.7%, and 41.7%, respectively, compared to the traditional hot-pressing composites. The dynamic mechanical analysis (DMA) revealed that the VARTM composite moduli in the temperature range of -50°C-200°C were doubled. The observations by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and mercury porosimetry confirmed that the interfacial compatibility between the kenaf fibers and the polyester resin was substantially improved.

Electromagnetic shielding properties of iron oxide impregnated kenaf bast fiberboard

“…As the Fe content increased from 0% to 6.8%, 15.9% and 18.0%, MOE was decreased from 2,875MPa to 2,729MPa, 2,487MPa and 2,007MPa accordingly. Xia et al (2015) reported that, the MOE of the kenaf fiber-unsaturated polyester composites was 4,186 MPa, which was in the same range of these presented results.…”

Dual-functional natural-fiber reinforced composites by incorporating magnetite

“…The composites were fabricated using the un-treated kenaf fibers, Kenaf/magnetite20, Kenaf/magnetite30, and Kenaf/magnetite40 through vacuum-assisted resin transfer molding (VARTM) process described in the previous research [43]. Briefly, the kenaf preform, with a dimension of 110 × 165 × 10 mm (width × length × thickness), was placed on the mold that was covered with a flexible polyethylene vacuum bag.…”

“…However, in this work the MOE was significantly increased. It might be contributed to the VARTM process, which could enhance MOE considerably compared with the traditional hot-pressing process [43]. TE, TS, and TEB of the four types of composites are compared in Fig.…”

“…To fabricate the kenaf fiber based composites with electromagnetic shielding and paramagnetic properties, magnetite particles were physically mixed with kenaf fibers. The mixture was fabricated into composite through the vacuum assisted resin transfer molding (VARTM) process, which was expected to improve the mechanical property of composites [43].…”

Growth, productivity, and utilization of kenaf (Hibiscus cannabinus L.): A promising fiber and fuel crop for Iowa

“…Other potential applications for bast and core are reinforcements in bioplastics and biocomposites, biofuel production, and other chemical end-use products Inoue et al, 2007;. Particularly, numerous studies have highlighted the competitiveness of kenaf bast fibers in the production of reinforced polymer products, using vacuum-assisted resin transfer molding (Xia et al, 2016a;Xia et al, 2015b). It has also been pointed that a kenaf fiber/polyester composites can replace glass fiber in the automotive industry, when impregnated and treated for water resistance, and that mechanical properties are often dramatically enhanced (Xia et al, 2015a;Xia et al, 2015c;Xia et al, 2016b).…”