Manufacturing and Characterization of Green Composites with Partially Biobased Epoxy Resin and Flaxseed Flour Wastes

Abstract

In the present work, green-composites from a partially biobased epoxy resin (BioEP) reinforced with lignocellulosic particles, obtained from flax industry by-products or wastes, have been manufactured by casting. In this study, the flaxseed has been crushed by two different mechanical milling processes to achieve different particle sizes, namely coarse size (CFF), and fine size (FFF) particle flaxseed flour, with a particle size ranging between 100–220 µm and 40–140 µm respectively. Subsequently, different loadings of each particle size (10, 20, 30, and 40 wt%) were mixed with the BioEP resin and poured into a mold and subjected to a curing cycle to obtain solid samples for mechanical, thermal, water absorption, and morphological characterization. The main aim of this research was to study the effect of the particle size and its content on the overall properties of composites with BioEP. The results show that the best mechanical properties were obtained for composites with a low reinforcement content (10 wt%) and with the finest particle size (FFF) due to a better dispersion into the matrix, and a better polymer-particle interaction too. This also resulted in a lower water absorption capacity due to the presence of fewer voids in the developed composites. Therefore, this study shows the feasibility of using flax wastes from the seeds as a filler in highly environmentally friendly composites with a wood-like appearance with potential use in furniture or automotive sectors.

Upgrading Recycled Polypropylene from Textile Wastes in Wood Plastic Composites with Short Hemp Fiber

“…It is observed that the addition of short hemp fiber as reinforcement has a direct impact on the water absorption capacity of composite materials. As the amount of fiber in the structure increases, the ability of the composites to absorb water tends to increase as well, mainly due to the hydrophilic nature of natural fibers as a result of the large amount of -OH groups present in hemicellulose and cellulose that tend to interact with water molecules easily [71,72]. The incorporation of PP-g-MA in the structure of the composites is noteworthy since this agent has an inhibiting effect on the water absorption capacity.…”

“…Figure 7a shows the obtained materials, and it is evident that the visual aspect significantly changed acquiring wood aspect. As can be seen in Figure 7b, the incorporation of SHF modified the color coordinates so that they acquired the appearance of woods like teak or eucalyptus [72,[76][77][78]. In this instance, rPP-H30-M took an appearance very similar to oak wood.…”

Green epoxy resin/date stone flour biocomposites: Effect of filler chemical treatments on elastic properties

“…Compared to inorganic fillers, the main advantages of natural fillers are their low cost, low density, renewal capacity, biodegradability, availability, and so on. [3][4][5] However, the lack of adhesion with polymer matrices presents a drawback for the widespread use of natural fillers in composites. The hydrophobic character of most polymers and the hydrophilic character of natural fillers negatively affect adhesion.…”

Manufacturing and Characterization of High‐Density Polyethylene Composites with Active Fillers from Persimmon Peel Flour with Improved Antioxidant Activity and Hydrophobicity

“…The existence of these voids in the internal structure of the composite materials enables water to enter, thus increasing their water absorption. [ 66 ] Another factor is the hydrophilic nature of the biofillers, due to the large number of hydroxyl groups present in PPF, belonging to phenols, proanthocyanidins, condensed tannins and fiber content (cellulose, hemicellulose and lignin), which promote water absorption by hydrogen bonding. [ 7,67,68 ] This effect is evident after the first week of immersion, especially in composites containing untreated PPF.…”