Wood Plastic Composites

Wood-plastic compositematerial is a new type of material which is based on wood or lignocellulose and other fibrous materials. This paper studies the characteristics of wood surface, explores the formation process of wood-plastic composite interface, and studies the main factors affecting the properties of wood-plastic composites, providing theoretical and technical basis for the development of high-performance wood-plastic composites. The properties of wood-plastic composite interface, the formation process and mechanism, and the effects of various composite factors on wood-plastic composite materials were analyzed.

The factors that affect the mechanical properties of composite materials include the surface free energy, surface polarity, and surface chemical functional groups. The change of surface free energy and surface polarity is the thermodynamic manifestation of the change of functional groups on the wood surface. Strongly polar wood surface hydroxyl groups will change their association state and quantity under different conditions, which will lead to changes in the free energy and polarity of the wood surface.

The physical and surface properties of plastics have an important effect on wood-plastic composites. The closer the surface polarities of the two, the better the compatibility.

The formation and strength of the wood-plastic composite interface are determined by the following conditions and measures:

The total surface free energy and non-polar surface free energy of the wood need to be higher than the surface free energy of the plastic to ensure that the plastic can wet and penetrate the wood surface; properly increase the surface roughness of the wood; eliminate small molecular substances on the wood surface and reduce wood-plastic composites The formation of a weak boundary layer at the interface; the surface of wood and plastic is modified to enhance the mutual adsorption and fusion of wood and plastic molecules.

In recent years, the research of wood-plastic composite materials has made rapid progress both theoretically and practically. Especially with the increase in the amount of used and discarded plastic materials, a large amount of discarded plastics cause pollution to the environment, and wood-plastic composite materials have become an important issue in the field of environmental protection as an effective way to recycle discarded plastics.