RESUMEN
The preparation of biocomposites from renewable and sustainable forestry residues is an effective method to significantly reduce the environmental pollution caused by synthetic materials such as plastics and synthetic fibers. This study is aimed at developing a clean process for the large-scale production of high-performance green biocomposites without involving any chemical adhesive. Adhesive-free biocomposites with superior mechanical properties were prepared using HCl ball milling pretreatment and in situ synthesis. The nano-Fe3O4 was uniformly dispersed in the cellulose matrix, and when the matrix was subjected to external forces, the stress concentration effect around the particles absorbed energy, thus effectively improving the mechanical strength of the matrix. The flexural strength and tensile strength of BWP(Fe3O4) samples were increased by 159.04 and 175.34%, compared to that of regular wood powder control samples. The lignin melts under high temperature and pressure and then forms a carbonized layer on the surface of the biocomposites during the cooling process, which prevents the rapid penetration of water from the surface and also gives the biocomposites good thermal stability. The results of this research can avoid the harmful volatiles generated by chemical adhesive than that of the traditional fiberboard process and effectively replace petroleum-based synthetic materials prepared using the addition of various chemical additives, making it conform to the concept of environmental protection and sustainability.
RESUMEN
Cellulose has attracted considerable attention as the most promising potential candidate raw material for the production of bio-based polymeric materials. In the last decade, significant progress has been made in the production of biopolymers based on different cellulose forms. In this study, cellulose was obtained in an innovative and environmentally friendly way, using boxwood powder. Crude cellulose was obtained by treating Buxus powder with an ethanol-acetic acid-water mixture. Refined cellulose was then obtained by treatment with an acidic sodium hypochlorite solution and alkaline hydrogen peroxide solution. The novel chemistry of cellulose prepared by this method promises to be not only green, but also highly desirable, because of its lower emissions and low cost. It is crucial for the future of the global polymer industry. The refined cellulose was subjected to a high-temperature hydrothermal treatment under two temperatures and time conditions, with temperature gradients of 120, 140, and 160 °C, and time gradients of 1, 2, and 3 h. The samples were subjected to infrared and thermogravimetric analyses. The cellulose undergoes dehydration and thermal degradation reactions during the heat treatment process, and the thermal stability of the residual is enhanced, compared with that of virgin cellulose. Between 120 and 140 °C, the hydroxyl and hypomethyl groups on the surface of cellulose are shed. Groups in the amorphous region of the polymer are the first to be shed. The dehydration reaction reduces the number of free hydroxyl groups on the surface of the cellulose molecules. The dehydration reaction was accelerated by an increase in temperature. Between 140 and 160 °C, the ß-(1,4)-glycosidic bond begins to slowly break and some furans are generated. The structure of cellulose undergoes reorganization during thermal treatment. The thermal stability of the modified material is greater than that of untreated cellulose.
RESUMEN
In the context of high-quality development, environmental issues are being paid more and more attention to, and the release of free formaldehyde has become a major problem that needs to be solved. Glueless plywood mainly adopts natural substances as raw materials, without adding chemical products, such as resin adhesives, and it does not contain harmful substances, such as formaldehyde. Glueless plywood is a green product that causes no pollution in the environment and no harm to the human body. In this study, the corresponding weak-phase components in boxwood were pre-delivered by an acidic environmental treatment, and the high-temperature and high-pressure compacting process produced a glueless boxwood panel with excellent water resistance and mechanical properties, while remaining environmentally friendly.
