In many parts of Asia, the fiber hemp has been in use since prehistoric times. Ancient records describe the use of hemp fiber in China 2800 B.C. during the early Christian era, production of hemp spread to the countries of Mediterranean Europe, and since then the fiber has come into widespread use throughout the world.
Like flax, hemp is a bast fibre. It becomes from the plant cannabis sativa, an annual of the family Moraceae, which grows to a height of 3m (10 ft) or more. The hemp plant is now cultivated in almost every European country and in any parts of Asia. Important producing countries include the Soviet Union, Yogoslavia, Roumania ad Hungary.
Production and Processing of Hemp Fiber:
The hemp plant is harvested and processed in a manner similar to that used for flax. Fiber is freed from woody matter by dew retting or water retting, followed by breaking and scotching. The fiber is softened by pounding it mechanically or by hand.
Hemp can be separated from the straw by a mechanical process more easily than in the case of flax. Green hemp is now produced commercially in this way.
Dyeing:
Hemp is used very largely in its natural state. When dyeing is necessary direct colors are often used. Basic dyestuffs provide bright shades, the fiber being mordanted with antimony and tannin.
Structure and Properties of Hemp Fiber:
Hemp is coarser fiber than flax fiber. It is dark in color and difficult to bleach. The fiber is strong and durable and is used very largely for making string, cord and rope.
Some Italian hemp is produced with great care. They are light in color and have an attractive luster similar to that of flax fiber.
Strands of hemp may be 2m in length. The individual cells are on average 13-26mm long. They are cylindrical in shape with joints, cracks, swellings and other irregularities on the surface.
Like flax fiber, the cells of hemp fiber are thick walled. They are polygonal in cross section. The central canal or lumen is broader than that of flax, however and the ends of the cells are blunt. The hemp is more lignified than flax fiber and is consequently stiffer.
Strength and Durability:
- High Tensile Strength: Hemp fiber is one of the strongest natural fibers, making it highly resistant to wear and tear.
- Durability: The fiber’s durability makes it ideal for products that require long-term use. Hemp fabrics can withstand repeated washings without degrading.
Absorbency:
- Moisture-Wicking: Hemp fiber is highly absorbent, quickly wicking away moisture from the skin. This property makes it ideal for clothing and textiles that need to remain dry and comfortable.
- Breathability: The fiber allows air to circulate, making hemp fabrics breathable and comfortable in hot climates.
Antibacterial Properties:
- Natural Resistance to Bacteria and Mold: Hemp fiber has inherent antibacterial and antifungal properties, which help in reducing odors and maintaining hygiene in textiles.
Thermal Conductivity:
- Insulating: Hemp fiber provides good thermal insulation, keeping the wearer warm in cool climates and cool in warm climates. This makes it suitable for all-season wear.
Sustainability:
- Eco-Friendly: Hemp is a highly sustainable crop. It grows quickly, requires minimal pesticides, and improves soil health through phytoremediation.
- Low Water Usage: Compared to other fibers like cotton, hemp requires significantly less water to grow, making it an environmentally friendly choice.
UV Resistance:
- Protection from UV Rays: Hemp fiber naturally offers some protection against ultraviolet (UV) rays, making it suitable for outdoor clothing.
Texture:
- Softens with Use: Although initially coarse, hemp fabric softens with each wash, becoming more comfortable over time. This makes it comparable to linen in texture.
Biodegradability:
- Environmentally Friendly Disposal: As a natural fiber, hemp is biodegradable, reducing its environmental impact at the end of its life cycle.
Uses of Hemp Fiber:
During its long history, hemp has been used for almost every form of textile material. It has been made into fine fabrics by skillful spinning and weaving or carefully produced fibre, notably in Italy where a hemp fabric is similar to linen is made. Now a day, hemp is used mainly for coarse fabrics such as sacking and canvas and for making ropes and twines.
Hemp can be cottonized by a process similar to that used for flax, so that the individual fibers are freed. Cottonized hemp does not spin easily alone but it gives useful yarns when mixed with cotton.
Textiles:
- Clothing: Hemp is used to produce a wide range of garments, including t-shirts, jeans, dresses, and outerwear. Its breathability and durability make it suitable for both casual and workwear.
- Home Textiles: Hemp is used in the production of home textiles like bed linens, towels, tablecloths, and curtains due to its strength and absorbency.
- Rope and Twine: Due to its tensile strength, hemp has historically been used to make ropes, cords, and twines, particularly for maritime uses.
Industrial Applications:
- Construction Materials: Hemp fiber is used to make hempcrete, a sustainable building material with excellent insulating properties. It’s also used in making fiberboards and insulation.
- Automotive Industry: Hemp is increasingly being used in the automotive industry for manufacturing biocomposite materials for car interiors.
- Paper Production: Hemp fiber is used in producing high-quality, sustainable paper products, as it has a higher yield per acre compared to wood pulp.
Personal Care Products:
- Skincare and Hygiene: Hemp fiber is used in making natural, biodegradable personal care products like exfoliating scrubs, bath mitts, and wipes.
Environmental Uses:
- Phytoremediation: Hemp plants are used to clean up contaminated soils through phytoremediation, as they can absorb heavy metals and toxins from the ground.
- Erosion Control: Hemp fibers are used in erosion control mats and blankets due to their strength and biodegradability.
Composites:
- Eco-Friendly Plastics: Hemp fibers are increasingly being used in the production of biodegradable plastics and composites, which are used in various industries, including packaging and construction.