Structure And Properties Of Hemp Fiber

Hemp fiber refers to the general term for fibers obtained from various kinds of hemp plants.

There are many varieties, including phloem fiber and leaf fiber.

The fibers obtained from various hemp plants include the phloem fibers of the cortex and dicotyledonous leaf fibers of the annual or perennial herbaceous dicotyledonous plants.

The bast fiber crops are ramie, jute, hemp, hemp (Han Ma), linen, Apocynum venetum and hibiscus hemp.

Ramie, linen, Apocynum and other cell walls are not lignification. The length and thickness of the fibers are similar to those of cotton. They can be used as textile raw materials, woven into various cool linen and summer cloth, and can be blended with cotton, wool, silk or chemical fiber.

Leaf fiber is thicker than phloem fiber and can only be made into rope.

Bast crops can also be used as raw materials for chemical, pharmaceutical and papermaking.

The linen fibers are bonded by glue, and the fibers must be removed when preparing.

Ramie and linen can be separated into single fibers.

Jute fibers are short and can only be separated into bundles of suitable size for spinning. This fiber bundle is called process fiber.

In the linen fibers used for textile industry, gum and other cellulose have more biological products. After scouring, the cellulose content of hemp fiber is still lower than that of cotton fiber.

The cellulose content is close to cotton (above 95%), the flax cellulose content is slightly lower than ramie, and the cellulose content of jute and Ye Xianwei is only about 70% or less.

The degree of orientation of cellulose macromolecules in Ramie and linen fibers is larger than that in cotton fibers, and crystallinity is good. Therefore, the strength of hemp fiber is higher than that of cotton fiber, up to 6.5 g / Dan, and the elongation is small, only half of cotton fiber, about 3.5%, which is more brittle than cotton fiber.

Ramie and linen fibers are smooth in surface, easy to absorb moisture, and moisture exudes faster in the atmosphere. The fibers are more straight and not easy to deform.

Egyptians used flax fibers for 8000 years, and the Egyptian mummy in the tomb was more than 900 meters long.

China used ramie as textile material as early as 4000 B.C. in the Neolithic age.

The remnants of ramie fabrics found in the relics excavated from Qianshan Yang, Wuxing, Zhejiang, were relics left before 2700 B.C.

It is the first choice of knitted fabrics in summer.

All hemp fibers are cellulose fibers, the basic chemical components are cellulose, and other non fibrous substances such as pectin, hemicelluloses, lignin, fatty waxes (collectively referred to as "colloid"), which are all associated with cellulose.

To remove the available fibers, it is necessary to separate them from the colloid (called degumming).

The content of cellulose in the chemical components of all kinds of hemp fiber is about 75%, which is similar to that of silk fiber.

The presence of components provides three important chemical properties for hemp fibers. It is very important for obtaining hemp fibers with spinnability. The acidic hydrolysis of cellulose means that 1 of the cellulose macromolecules and the 4- beta glycoside bonds will break up at suitable hydrogen ion concentration, temperature and time, resulting in the decrease of the degree of polymerization of cellulose and the change of cellulose properties to varying degrees.

After hydrolysis, the degree of polymerization of cellulose decreased, the strength decreased, the dissolution increased in the lye, and the moisture absorption ability changed.

Therefore, in the process of degumming, proper treatment of technological parameters should be followed.