ABSTRACT
The present paper describes the application of two types of food-industry by-products, brewers' spent grain (BSG), and coffee silverskin (LK) as promising alternatives for the conventional beech wood flour (WF) for wood-polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and LK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and LK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 °C guarantees a safe processing window for polyethylene-based materials.
ABSTRACT
Due to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different raster angles (45°, 55°, 55'°, 60° and 90°) on the static, as well as rarely investigated, dynamic mechanical properties of 3D printed acrylonitrile butadiene styrene (ABS) materials. Configuration named 55'° was based on the optimal winding angle in filament-wound pipes, which provides them exceptional mechanical performance and durability. Also in the case of 3D printed samples, it resulted in the best impact strength, comparing to other raster angles, despite relatively weaker tensile performance. Interestingly, all 3D printed samples showed surprisingly high values of impact strength considering their calculated brittleness, which provides new insights into understanding the mechanical performance of 3D printed structures. Simultaneously, it proves that, despite extensive research works related to FDM technology, there is still a lot of investigation required for a proper understanding of this process.
