Composite parts, used in transportation industries, are manufactured using vacuum‐assisted resin transfer molding (VARTM) and non‐woven glass fiber mats that are optimized for impregnation, fiber volume fraction (Vf), and composite properties. However, such optimized hemp and flax mats are not available. Extending the research on hemp mats manufactured using air‐laying, the effect of needle depth (2 or 8 mm) and punch density (0–72 punches/cm2) used to bind the fibers in the mat together, as well as consolidation pressure (101–560 kPa) applied during manufacturing, on mat permeability and composite properties were studied. Non‐woven flax mats exhibited heterogeneity in spatial distribution of areal density (GSM) and fiber distribution. This, together with the distribution in flax fiber diameter and properties, resulted in large scatter in the measured composite properties. The out‐of‐plane permeability and the consolidation of the mat decreased with increase in punch density and depth. This, together with the variation of Vf in the starting mat, resulted in complex variation in the Vf in the composite. 30‐P mat, with tightly bound fibers, resulted in optimal composite properties at VARTM (101 kPa) pressure while 0‐P and 72‐P mats, with loosely bound fibers, resulted in optimal properties at 560 kPa.

Vacuum-assisted resin transfer molding (VARTM), used in manufacturing medium to large-sized composites for transportation industries, requires non-woven mats. While non-woven glass mats used in these applications are optimized for resin impregnation and properties, such optimized mats for natural fibers are not available. In the current research, cattail fibers were extracted from plants (18–30% yield) using alkali retting and non-woven cattail fiber mat was manufactured. The extracted fibers exhibited a normal distribution in diameter (davg. = 32.1 µm); the modulus and strength varied inversely with diameter, and their average values were 19.1 GPa and 172.3 MPa, respectively. The cattail fiber composites were manufactured using non-woven mats, Stypol polyester resin, VARTM pressure (101 kPa) and compression molding pressures (260 and 560 kPa) and tested. Out-of-plane permeability changed with the fiber volume fraction (Vf) of the mats, which was influenced by areal density, thickness, and fiber packing in the mat. The cattail fibers reinforced the Stypol resin significantly. The modulus and the strength increased with consolidation pressures due to the increase in Vf, with maximum values of 7.4 GPa and 48 MPa, respectively, demonstrating the utility of cattail fibers from waste biomass as reinforcements.

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Vacuum Assisted Resin Transfer Molding (VARTM), used to manufacture medium to large sized composites for transportation industries, require non-woven mats. While non-woven glass mats used in these applications are optimized for resin impregnation and properties, such optimized mats for natural fibers are not available. In the current research, cattail fibers were extracted from plants (18–30% yield) using alkali retting and nonwoven cattail fiber mat was manufactured. The extracted fibers exhibited a normal distribution in diameter (davg. = 32.1 µm) and the modulus and strength decreased with increase in diameter with average values of 19.1 GPa and 172.3 MPa, respectively. The cattail fiber composites were manufactured using non-woven mats, Stypol polyester resin, and VARTM (101 kPa) and compression molding pressures (260 and 560 kPa) and tested. Out-of-plane permeability changed with Vf of mats, which was influenced by areal density, thickness, and fiber packing in the mat. The cattail fibers reinforced the stypol resin significantly. The modulus and the strength increased with consolidation pressures due to increase in fiber volume fraction (Vf), with maximum values of 7.4 GPa and 48 MPa, demonstrating the utility of Cattail fibers from waste biomass as reinforcements.

No abstract