What is marijuana?

Summarize the history of hemp planting, processing and utilization, the output at home and abroad, the physical and chemical properties of hemp fiber, and the development and research of hemp textile products at home and abroad.

hemp originated in Asia. In ancient times, cannabis was distributed in China, Central Asia, Himalayas and Siberia. China has the longest history of growing cannabis. Its history can be traced back to the time of Emperor Shennong in 27O BC. Our ancestors planted and retted hemp and started rope-making industry. Later, bast plant fibers were treated by retting and boiling kudzu, and hemp fibers were used as textile raw materials by rubbing, spinning, dropping and pickling techniques. Spin into yarn and weave into cloth. The fabrics include cattle clothes, mourning clothes (commonly known as wearing hemp to mourn), dresses, Korean clothes, battle clothes, tributes and other hemp clothes with different thicknesses. The hats of princes and nobles in the Western Zhou Dynasty were called hemp crowns, which were made of 3 liters of burlap as fine as dacron today. Cannabis fragments unearthed from Shang Dynasty site in Taixi Village, Gaocheng, Hebei Province, China have a history of more than 3,4 years. That is to say, in more than 18 BC, our ancestors mastered hemp retting and textile technology. In some years BC, he mastered the technology of making paper from hemp.

around 15 BC, cannabis was introduced to Europe one after another (some records are in the Middle Ages). It was not until the eighth century that India began to use cannabis. They cultivated cannabis mainly for medicinal purposes. In the middle of last century, France planted 1, hectares of cannabis, mainly for rope making and later for paper making. In World War II, after Japan attacked and occupied Pearl Harbor, the supply line of the United States was cut off. In order to meet the military needs, the United States was forced to develop its own cannabis production.

At present, cannabis is produced almost all over the world, but it is concentrated in countries in Asia, America and Eastern Europe, and Europe is concentrated in France. The world's hemp production, the highest annual output of hemp fiber was 1.14 million tons in 1955, and the lowest in 1993, with an annual output of 18, tons, generally between 2, and 29, tons. The output of cannabis in China was as high as 16, tons in 1958 and as low as 23, tons in 1977, with an average annual output of 4, to 14, tons.

It can be seen that the total output of cannabis in China ranks first in the world. The European isomorphism is concentrated in France. China's main producing areas are Shandong, An Wei, Henan, Hebei, Gansu, Shanxi, Yunnan, Ningxia, Heilongjiang, Jilin, Liaoning and other provinces. Among them, Shandong Laiwu hemp, Shanxi Lu 'an hemp and Hebei Yuxian hemp are the best. Hemp in Shandong Province is mainly distributed in Tai 'an, Laiwu, Philadelphia, Weifang, Jining, Heze and other places. Tai 'an area is a key producing area of traditional cannabis. Because of the high yield, good quality and high hemp yield, especially Taian and Laiwu hemp enjoys a high reputation in the domestic and foreign markets. In the past, 15, mu was planted in Tai 'an area, with an output of 2, tons. Because in recent years, hemp handmade products have been gradually replaced by chemical fiber and plastic products. In 1984, the planting area was reduced to 3, mu, and the output was reduced to 56, tons. In recent years, due to hemp heat and degumming success, the output has rebounded.

Cannabis belongs to Cannabis or Moraceae, which is panicum miliaceum, and the fiber is bast fiber. Cannabis can be harvested after about 15 ~ 2 days after sowing. Cannabis plants are dioecious (monoecious plants have been cultivated). In ancient times, the female of marijuana was called ju hemp, and the male was called xi hemp (the imperial court in the Western Zhou Dynasty set up a ceremonial official). There are also early-maturing and late-maturing varieties of cannabis in China. The quality of hemp fiber is better than that of male plant, and the hemp yield is higher. The female plant is poor and the hemp yield is low. Early maturity hemp fiber is better than late maturity hemp fiber. Hemp single fiber is tubular and has bifurcation at the tip. The surface has knots and longitudinal stripes, without distortion, similar to flax. The cross section is slightly oval or polygonal, with a central cavity. The degummed hemp fiber is torn by hand, and the fibers are bonded by residual strands, showing a network structure. If degumming is too complete, it will become short fiber. Hemp single fiber length is generally 15 ~ 25mm, fiber width is 15 ~ 3mm, and fiber color is yellowish gray to brown). After bleaching, the color is white and shiny, and the cellulose content in the fiber is about 77%, the specific gravity is about 1.49, and the degree of polymerization is 22 ~ 23.

marijuana can be said to be a treasure; Hemp fiber can be used for rope making, paper making, spinning and weaving. Hemp fiber has no odor when burning, and its ash is white, so it is the first-class raw material for making high-grade cigarette paper. Hemp seeds have an oil content of 3%, and are delicious and edible. Besides, they can also be used to make drying oil, paints and dyes. Hemp cake is a kind of concentrated feed with high nutritional value and an organic fertilizer with high fertilizer efficiency. Hemp stalks can be used to make sound insulation boards for buildings. The hemp fiber with large hemp core is used to make paper, which has good quality, low cost and low sewage discharge. The alcohol extract of hemp stems, leaves and flowers can be used as hypnotic and sedative in medicine, and its phosphoric acid preparation can also be used as a tonic for anemia, neurasthenia and other diseases. In Chinese traditional medicine. Cannabis kernel is still used for defecation and birth promotion.

properties of hemp fiber; The spinnability of hemp is inferior to ramie and superior to flax. Hemp has excellent corrosion resistance and water resistance is the highest among all natural fibers.