A Method of Managing Waste Oak Flour as a Biocomponent for Obtaining Composites Based on Modified Soybean Oil

The aim of the present research was the development of a management method for wood-processing waste that was obtained during the production of parquet flooring. Currently mostly useless, such waste mainly ends up in landfills. The oak waste flour was used as a reinforcement material for epoxy biocomposites based on the polyaddition product of epoxidized soybean oil and bisphenol-A (ESBO_BPA). The biofiller was subjected to mercerization, acetylation, and diisocyanate modification to increase the typically poor compatibility between the highly hydrophilic wood fibers and the hydrophobic polymer matrix. Among the analyzed epoxy biocomposites, which contained about 60% raw materials of natural origin, it was found that the best mechanical properties were recorded for cured samples of the ESBO_BPA composition filled with 5 wt % of oak flour mercerized using a 5% solution of NaOH. It was also proven that a higher concentration of alkali deteriorated the mechanical-strengthening properties of the wood filler. The acetylation of the biofiller independently in the best elimination of hydroxyl groups from its structure also removed irregular strips and smoothed its surface. This resulted in a poorer wettability of the oak flour surface by the polymer and consequently an easier pullout of the filler from the polymer matrix and worse mechanical properties of the wood/epoxy composite. To the best of the authors' knowledge, the present research was the first to examine the possibility of the application of parquet flooring post-production wood flour in biomaterials based on a polyaddition product of epoxidized soybean oil and bisphenol-A.