Strengthen the Development and Application of High Value-Added WPC Materials
With the continuous expansion of the output and application range of wood-plastic composites, problems such as poor toughness and creep are gradually exposed. At present, there are many types of research on the strengthening and toughening of wood-plastic composites. The main methods include adding reinforcers (rigid particles, reinforced fibers), improving the toughness of plastic matrix (plastic modification treatment), and using compatibilizers to improve the interface compatibility between biomass fibers and polymers. Reinforced fiber has been widely used in polymer composites, and it also has more effective strengthening and toughening effect on plastic wood. Adding the fiber to the WPC composite material to prepare the multi-component composite material composed of thermoplastic plastic, wood powder and fiber can greatly improve the strength of WPC composite material. With the rapid development of material science, more and more kinds of fiber are used to strengthen composite materials, such as glass fiber, carbon fiber, basalt fiber, mineral cotton, polyester fiber, etc. In recent decades, natural cellulose fiber has been increasingly used to strengthen polymer materials due to its advantages of environmental protection and no pollution. These fibers can be used to improve the mechanical properties of wood-plastic composites. Plastic wood composite materials with its unique environmental advantages have developed rapidly for more than 20 years. After experiencing the bottleneck period at the present stage, the next step is bound to develop towards high efficiency, high performance and high value-added WPC materials. It is an effective method to add reinforced fiber to improve the strength of wood-plastic composites, especially to improve the impact resistance of wood-plastic composites, and it is of great significance to expand the application of wood-plastic composites. However, fibre-reinforced plastic and wood composites are still in the research stage, and there is still a long way to go before they are industrialized. Just for the ordinary plastic wood composite material, domestic current extrusion production efficiency is generally low, improve the stability of the production efficiency can be from the raw material, formulation optimization, the improvement of equipment and technological level and improve the aspects such as one of the most important is the “extrusion equipment and process improvements, implement efficient plasticizing, cold extrusion, accurate setting and effective cooling is the key to improve the efficiency of extrusion production. For fiber reinforced high performance, High value-added WPC materials, to achieve rapid industrialization, the improvement of production efficiency is imperative. The fibers are easy to be “bridged” during feeding, and they are not easy to disperse evenly and agglomerate in the matrix. In addition, the excessive dispersing shear will lead to the fracture of most of the fibers, especially for the soft flexible fibers, which are more obvious. To solve these technical problems, it is necessary to perfect and improve existing equipment. For example, in the mixing equipment, the special screw can be arranged for the melt of plastic-wood composite material with high viscosity characteristics, so as to achieve the effect of fiber dispersion and not to produce excessive shear to the fiber. Continuous fiber has been widely used in reinforced polymer composites, and there are many molding methods, such as pultrusion method, injection method, winding method, impregnation hot pressing method, etc., whose strengthening effect is obviously better than short cut fiber. At present, there are few types of research on continuous fiber reinforcement of wood-plastic composite materials, and no mature reinforcement technology has been formed. The difficulties still lie in the low fluidity of the melt of wood-plastic composite materials and the limitations of molding processing. Current render the WPC in public for the vast majority of added value is not high, the low performance of decorative materials, such as outdoor flooring, a pavilion, fences, exterior wall hangs Taiwan, indoor hanging tent and interior wall decorative plate, there is the little higher value of car seats, interior and doors and windows, furniture and other requirements for strength and shock resistance high value-added WPC materials. The expansion of these market areas will increase the demand for high-performance wood plastic composite decking materials, thus driving the industrial development of fibre-reinforced plastic-wood composite materials.