Prospects of Straw-Biomass Wood Plastic Composite Materials

With the increasing shortage of wood resources, the choice of raw materials for traditional wood plastic composite materials has begun to turn to crop stalks. Straw stalks, reed stalks, rice stalks, cotton stalks, etc., Are important crop stalk resources, which are large in quantity and inexpensive, renewable, and degradable. , Has a greater use-value. Traditional utilization methods are difficult to produce high value-added industrial products, and the comprehensive utilization rate is low. A large amount of straw has not been effectively and rationally used for a long time, which has caused it to become a kind of waste resource. In addition, improper treatment methods such as incineration waste valuable resources.

Formed a New Demand For “Substituting Straw For Wood”

In recent years, the industry has gradually formed a new demand for “substituting straw for wood”. In the field of plastic-wood composite material manufacturing, the concept of straw-plastic composite material has been first proposed in recent years. Straw-Biomass wood plastic composite (SPC) is a kind of less than annual plant fiber growth, such as straw, cotton stalk, bagasse, etc. as raw materials, after crushing and interface compatibilization treatment, and a certain proportion of thermoplastic A new type of environmentally friendly and recyclable material that combines the characteristics of bio-based materials and plastics, prepared by extrusion, hot pressing, or injection molding processes with additives. Under the background of current sustainable development, more and more attention is paid to renewable resources, and straw is used in the production of plastic-wood composite materials, turning waste into treasure, and producing green and environmentally friendly wood plastic composite hollow decking products with higher added value, Which not only expands the utilization of straw, relieves the contradiction between the supply and demand of wood resources, but also injects fresh blood into the plastic wood industry, and has far-reaching significance for strengthening the recycling of agricultural and forestry surplus resources and reducing environmental and ecological pressure.

Make It Difficult To Increase The Straw Component Content In The Straw-plastic Composite Material

Studies have shown that the surface of straw fibers contains strong polar hydrophilic groups, which are difficult to form good interface compatibility with plastics with strong surface hydrophobicity. Therefore, how to solve the poor interface compatibility between straw and plastic and optimize the bonding performance of the two interfaces is the top priority of the research on straw-plastic composites. It is worth noting that compared to wood flour/bamboo flour, there is a layer of biomass lipid components on the surface of straw, which inhibits the penetration of glue into the straw. In addition, the direction of the straw powder fiber duct is single and the fiber loading rate is low. , Weaken the penetration of the straw fiber after the plastic is melted, and make it difficult to increase the straw component content in the Straw-Biomass wood plastic composite material. Therefore, when the straw is used to produce wood plastic composite materials, the interface modification process will be different from traditional plastic-wood composite materials and has certain particularities. Related technologies and research results of interface modification in the preparation of straw-plastic composite materials include physical modification, chemical modification, biological modification and other methods.

The chemical composition of straw and wood is similar, but the ratio is different. The ratio of the composition of straw produced in different regions will be slightly different. Taking the chemical composition of straw and spruce as an example, the cellulose content of wheat straw is relatively low, but The content of ash minerals and hot water extracts is much higher than that of wood, and they are mainly concentrated in the outer layer of straw. The main component of the hot-water extract of straw is the waxy layer on the surface of wheat straw. As a major agricultural country in the world, it is also a major consumer of plastic products. A large amount of straw and recycled plastic produced every year has laid a good raw material foundation for the production of straw-plastic composite materials. Overcoming the incompatibility of the interface between straw and plastic is a boost to the straw-plastic composite A key issue that must be solved for the promotion of materials in the wood plastic composite manufacturing industry.

Incompatibility Of The Plastic To The Surface Of The Polar Straw

The interface modification technology of the straw-plastic composite material is different from the traditional interface modification technology of the straw man-made board. The main reason is the incompatibility of the plastic to the surface of the polar straw. For this reason, the interface modification technology of Straw-Biomass wood plastic composite materials mainly promotes mechanical bonding by increasing the specific surface area and voids of the bonding from a physical point of view. Specific implementation methods such as mechanical pulverization, high frequency and high temperature and ion treatment; reduce the surface of straw from a chemical point of view Polarity or increase the polarity of the plastic and enhance the binding ability of the plastic to the straw through the compatibilization of the coupling agent. The specific implementation methods include maleic acid grafted plastic polymer, coupling agent grafted straw and straw alkali, Means of biological treatment.

However, in order to realize the industrialization of the interface modification technology of straw-plastic composite materials, many practical problems still need to be faced. Straw-plastic composite material is a beneficial supplement to the wood-plastic industry. It is completely comparable to wood-plastic materials in terms of raw material costs, product strength, durability, and environmental protection, and even has better mechanical properties. The unique superiority of straw plastic makes its products very promising in the high-end market. Although the new straw-plastic material has a good development prospect, the modification and plasticization process in its production process is more complicated, and the production cost is high, which is not conducive to the competition in the low-end market; its product development is still in its infancy. The production and application of new materials also require continuous R&D and innovation.

Keywords:

Wood Plastic Composite Materials

Substituting Straw For Wood

Straw-plastic Composite Materials

Wood-Plastic Materials

Plastic-Wood Composite Material

Straw-Biomass Wood Plastic Composite