Effect of enzymatic treatment of flax on fineness of fibers and mechanical performance of composites

Abstract

The application of enzymes as alternative to dew retting of flax was studied in correlation to the characteristics of composites reinforced with these natural fibers. Fiber fineness and mechanical properties of biocomposites were evaluated. Furthermore, moisture absorption by biocomposites was studied and fracture surfaces were investigated using Scanning Electron Microscopy. Compared to dew retted fiber composites, improvements in mechanical performance can be observed for composites impregnated with fibers extracted after enzymatic treatments. All enzymatic treatments resulted in finer fibers than green fibers and led to biocomposites with a reduced equilibrium moisture content and lower diffusion coefficient. This study illustrates the high potential of enzymatic retting, in particular with polygalacturonase. Also, the manual extraction procedure used, produced fibers with an E-modulus up to 84 GPa and strength up to 800 MPa, likely due to reduced fiber damage, which illustrates the hidden potential of flax fibers.

Structures, Properties and Potential Applications of Corncob Residue Modified by Carboxymethylation

“…Furthermore, the growing concern about environment problems and the potential shortage of fossil resources have promoted the interest in developing sustainable materials. Therefore, many scientists have investigated the possibilities to prepare composites with plant fibers such as flax, cotton, hemp, corncob and various grasses [1][2][3]. Currently, the agricultural and forestry residues have been considered as the rich and important natural fibers resources.…”

Flax treatment with strategic enzyme combinations: Effect on chemical fiber composition and ease of fiber extraction

“…Previous studies on enzymatic treatment of flax stems within our research group have shown that polygalacturonase, pectate lyase and xylanase showed most potential for the extraction of flax fibers [11,12]. Hereby, chemical characteristics as well as mechanical properties, e.g.…”

“…unidirectional longitudinal and transversal composite strengths, were evaluated. Purified fibers with a cellulose content of 79 w/w % were obtained after enzymatic treatment with polygalacturonase while exhibiting improved mechanical properties [11,12]. The improvement of mechanical properties of composites impregnated with fibers extracted after enzymatic treatment of flax can be attributed to the increase in cellulose content of the fibers combined with a good orientation of the micro fibrils and the reduction in pectin content [11,12].…”

“…Purified fibers with a cellulose content of 79 w/w % were obtained after enzymatic treatment with polygalacturonase while exhibiting improved mechanical properties [11,12]. The improvement of mechanical properties of composites impregnated with fibers extracted after enzymatic treatment of flax can be attributed to the increase in cellulose content of the fibers combined with a good orientation of the micro fibrils and the reduction in pectin content [11,12]. Zhang et al [13] also reported the key role of polygalacturonase in the retting process by degradation of non-methylated polygalacturonic acid in the middle lamella pectin which was later on confirmed by Evans et al [14].…”

Surface Modification of Flax Yarns by Enzymatic Treatment and Their Interfacial Adhesion with Thermoset Matrices

“…In particular, the use of enzymes for textile and natural fibre modification is swiftly growing. The enzymatic treatment represents a green way to modify natural fibres, and in literature enzymatic treatments have been used with two final aims: (i) the extraction of bast fibres from non-fibrous tissues in stems as an alternative to dew retting [24,25], and (ii) the surface modification of fibres already extracted in order to reduce hydrophilicity and increase thermal stability [21,26]. In these latter studies, the enzymatic treatment was reported to be able to remove undesirable substances like pectin, hemicelluloses, lignin and waxes from the surface of the fibres, improving fibre/matrix adhesion, moisture resistance and thermal stability.…”