Coordination And Incompatibility Of Hemp Fibers

China is a large country of hemp fiber production. At the end of last century, the processing capacity of ramie fiber was only 700 thousand spindles. In recent years, for various reasons, China's production capacity has stabilized at 250 thousand ingots, down from 700 thousand yuan at the end of the last century. ramie The planting area also decreased (1 million 990 thousand mu in 2006, and 500 thousand mu in 2010). Of course, the world's hemp fiber processing industry also has the same situation.

Glass fiber reinforced with traditional reinforced materials. carbon fibre Compared with the composites made of hemp fibers as reinforcing materials. Price Low cost, low density, reproducible and biodegradable, with high strength and modulus, it can be used as fireproofing and sound insulation materials in construction industry, sulphur materials, cement templates, ecological packaging materials, cushioning materials in the packaging industry, interior decoration boards, automotive parts and other functional materials in the automotive industry.

The developed countries have invested a lot in the application of hemp fiber composites. According to the information provided by the European cannabis Industry Association, about 15 to 20 companies in the European Union are mainly engaged in the production and processing of hemp fibers, and 5 to 10 such companies are distributed in Eastern Europe. The main companies are Hemcore in the UK, HempFlax and Hemp2ron in Holland, LCOA in France, and BaFa in Germany.

Even in developing countries, much attention has been paid to the research of hemp composites. Turkey, Bangladesh, Malaysia, India, Brazil and other countries all have hemp fibers for the study of composite materials. Only India has several national research institutes to study the application of hemp. The applications of these composites are concentrated in the automotive and construction industries.

For automobiles, lightweight, safety, comfort and environmental protection are the main trends of the development of the world's automobile industry. Plastic and its composite materials are important automotive materials. On average, the amount of non-metallic materials per vehicle has reached 105kg, which accounts for 8% to 12% of the total vehicle quality. The number of spare parts based on PP is different depending on the type of vehicle, involving 60~70 kinds of products, and plastics can reduce the weight of parts by about 40%.

Hemp composite materials are used as automotive parts with green products, reducing vehicle weight, reducing manufacturing costs, improving vehicle collision resistance, sound insulation, and material recovery.

In the automotive industry, hemp fiber composites are mainly used for door panels for car interior panels, sundries for drivers, freight car floors, spare tire covers, seat backs, and can also be used for dashboards, seat armrest, roof interior, sun visors, luggage compartment decorative panels, etc.

The biggest advantage of hemp composite material used as building materials is that the maintenance workload is small, no crack deformation, moth proofing, rat biting prevention, good durability, long service life, long water absorption rate, no decay, etc. It can be used for the manufacture of structural parts, such as horizontal trunk, handrail, window sill, doorframe, footplate, station shed, etc. there are fences, arches, ornaments and so on for non structural materials. It is mostly used for commercial and civilian buildings.

Linen fibers are made of heat insulation panels and device liners in European patents. Germany also has the patent of using hemp as storage tank. By applying a conductor or semiconductor to the exterior, it can also be used for electrical engineering.

The advantages of hemp fibers as composite materials are low cost, recyclability, and less energy consumption. They can be used in some or all of them instead of glass fiber. The reason is that it has high specific modulus and low specific gravity (~40Pa and 1.29), and glass fiber is ~30GPa and 2.5. The main drawback of natural fibers is strong water absorption and poor adhesion to resin.

Therefore, the main objective of the research and development work is to improve the surface morphology of hemp fibers through various means, choose or synthesize new coupling agents to increase the bonding strength between fiber and resin, reduce the affinity between fiber and water vapor through various pre-treatment, and reduce its hygroscopicity so as to make the environmental coordination materials more coordinated.

China is a large country of hemp fiber production, and hemp fiber reinforced composites will have a wide range of applications.