A series of investigations was undertaken regarding the biorefining of biomass for the recovery of multiple high-value products. The overall objective was to develop a simple, selective breakdown approach for flax shive, addressing three specific research areas: material properties; extraction processing; and product purification. This thesis includes five published papers and additional research all related to the topic. Flax shive represents the woody residue left over after removing fibre from flax straw. It is composed of lignified xylem tissue. Flax shive is readily available in large quantities, at low cost, and with relatively consistent particle-size and composition characteristics. Frictional behaviour investigations of bulk flax shive showed differing effects for addition of alcohols versus water. Adding any liquid significantly increased internal friction. The wall friction effects, however, depended on the liquid. Friction was increased significantly by water, but not as much by alcohols. Absorptive behaviour of flax shive, specifically liquid-holding capacity, was assessed using five liquids and compared to three other biomass materials. Flax shive was found to be a comparatively poor absorbent, a desirable behaviour for a feedstock used in aqueous- or alcohol-based processing. The first step extraction employed sodium ethoxide catalyst in anhydrous ethanol. Yield of solvent-soluble organics varied linearly with catalyst concentration. At 1.0 M the yield was 54.5 ± 14.5 mg/g dry basis (db). Analyses using 1H NMR consistently showed extracts to be phenolic in nature, and to contain no carbohydrate constituents. The second step extraction of hemicellulose polysaccharides was done using aqueous 1.0 M sodium hydroxide. The yield of carbohydrate precipitates was consistent, 99.4 ± 5.1 mg/g (db), and was unaffected by pretreatment. Analyses of polysaccharide backbone monomers showed consistently high molar ratios of xylose-to-glucose, i.e., 25.5 ± 3.4, with no mannose present. These results suggested a high concentration of glucuronoxylan polymer, likely greater than 90% by mass, with no glucomannan present. Economic evaluation showed two-stage extraction of high-value products to be a potentially viable business. Such processing also tied directly to government polices aimed at increasing value-add from agricultural materials. Overall, flax shive was found to be a desirable feedstock for recovery of high-value bio-products.

A series of investigations was undertaken regarding the biorefining of biomass for the recovery of multiple high-value products. The overall objective was to develop a simple, selective breakdown approach for flax shive, addressing three specific research areas: material properties; extraction processing; and product purification. This thesis includes five published papers and additional research all related to the topic. Flax shive represents the woody residue left over after removing fibre from flax straw. It is composed of lignified xylem tissue. Flax shive is readily available in large quantities, at low cost, and with relatively consistent particle-size and composition characteristics. Frictional behaviour investigations of bulk flax shive showed differing effects for addition of alcohols versus water. Adding any liquid significantly increased internal friction. The wall friction effects, however, depended on the liquid. Friction was increased significantly by water, but not as much by alcohols. Absorptive behaviour of flax shive, specifically liquid-holding capacity, was assessed using five liquids and compared to three other biomass materials. Flax shive was found to be a comparatively poor absorbent, a desirable behaviour for a feedstock used in aqueous- or alcohol-based processing. The first step extraction employed sodium ethoxide catalyst in anhydrous ethanol. Yield of solvent-soluble organics varied linearly with catalyst concentration. At 1.0 M the yield was 54.5 ± 14.5 mg/g dry basis (db). Analyses using 1H NMR consistently showed extracts to be phenolic in nature, and to contain no carbohydrate constituents. The second step extraction of hemicellulose polysaccharides was done using aqueous 1.0 M sodium hydroxide. The yield of carbohydrate precipitates was consistent, 99.4 ± 5.1 mg/g (db), and was unaffected by pretreatment. Analyses of polysaccharide backbone monomers showed consistently high molar ratios of xylose-to-glucose, i.e., 25.5 ± 3.4, with no mannose present. These results suggested a high concentration of glucuronoxylan polymer, likely greater than 90% by mass, with no glucomannan present. Economic evaluation showed two-stage extraction of high-value products to be a potentially viable business. Such processing also tied directly to government polices aimed at increasing value-add from agricultural materials. Overall, flax shive was found to be a desirable feedstock for recovery of high-value bio-products.

Limited information exists regarding the processing parameters and extent of reinforcing potential natural fibers have in polymer matrices. The five natural fiber mats studied were low shive flax, mid shive flax, high shive flax, hemp and kenaf. The parameters characterized were fiber size, wax content, surface contact angle, and shive content. The compressive force and unsaturated permeability was measured for each mat, and composites were constructed and tested using selected mats in a soy-based polyurethane (PU) matrix. All mats exhibited a viscoelastic behavior under compression, and an increase in shive content correlated with an increase in relaxation. The presence of shive and larger fiber size increased the permeability. Higher wax content and contact angle lowered the permeability. The mechanical properties for all composites performed better than the neat PU, showing there was matrix to fiber adhesion and load transfer. Hemp outperformed the other fibers studied in all mechanical tests.