The article is devoted to solving of actual questions linked with improving of the technological properties of flax fiber to expand the possibilities of its use in the composites industry. The multidirectional dependences of the influence of the polymer components content of scutched flax on the linear density, flexibility and specific strength of flax complexes was estimated. The multidirectional influence of different lignin structural formations to change the indicators with the optimum residual content of lignin is 3 wt% was demonstrated. A variant of enzymatic treatment for the development of the fiber pore structure was proposed. This variant provides the use of products forming after polysaccharide enzymatic destruction as reagents to destruct the large inter-fiber lignifications lowering the crushing uniformity of bast fiber bundles and the material strength properties impair. A 4-fold increase in the internal free volume and formation of nanoscale cavities on the fiber surface was demonstrated using the low-temperature adsorption of nitrogen and scanning electron microscope method. This is useful to improve the interfacial adhesion of the polymer binder. The transformation of lignin into a nanodisperse state was confirmed by the dynamic light scattering, Fourier-transform infrared and ultraviolet spectroscopy methods. As a result of the migration of depolymerized lignin into the structure of elementary fibers increases the strength of a linen fabric by 1.4–1.7 times and decreases its variation coefficient for breaking load by 2–2.7 times, and also improves its lightfastness and decreases the strength losses during insolation by 1.6–2 times.
