Introduction
The word flax is derived from the old english word fleax. The tutons referred to it as flakso, coming from the teutonic root flesh, to plait. The linen is the term applied to the yarn spun from the flax fibers and to the cloth or woven fabrics from this yarn. The flax fiber is classified as a natural, cellulose, bast and considered to be a heavy fibre. It is for this reason that most linen textile materials are of light construction. Thick linen textile materials would be uncomfortably heavy to wear.

Cultivation
Flax is a bast fiber and occur in dicotyledonous plants between the outer bark and the woody central cylinder. Each fiber consist of sclerenchymous cells (also known as bast and hence the name) overlapped in such a way that they produce continuous filaments. There are more than hundered species of flax plant but Linum Usilatissimum is the commercially most important variety.

Flax plants are grown in a region from sea-level to four thousand feet. Flax grows in almost any climate or on any soil. However, the best fibers are grown in temperate regions, but light, sandy and clayey soils should be avoided. The luxurious growth of the plant exhaust the soil so that flax can be grown at an interval of about seven years in the same ground. The soil which is moist, friable, fertile and well drained is the most suitable for flax cultivation.

Collection of fibers from the plant
The first stage for obtaining the fibers from the flax plant is called retting which consist in softening of flax in water. In the farmentation, bacteria developed in the process degrade the partitions of the softer cells of the bark, leaving the fibre cells unaffected thereby facilitating the separation of the fiber bundles from the bark and the woody core of the stalk. The retting process takes place in about three days after which the straw is removed and drained. A conveyor belt takes it to a drier, where hot air is passed to and fro through the straw. The straw is stacked for about six weeks to mature.

After drying it is subjected to breaking, the first mechanical process done either mechanically or in a stamping mill in which driven rollers crush and break the flax. Scutching is the next mechanical operation carried out in which the broken flax stalks are placed over the edge of scutching bench and worked with a wooden knife, when the wooden particles are separated from the fibers. The third process which is carried out to split up and separate the fibers clinging together without breaking them is the combing or hackling of the flax. This is carried out in a flax-comb, consisting of a board set with steel spikes; usually simple hand combs with teeth set in a series of circles of decreasing size are used. The final product thus obtained is the fine, long flax fiber with pale golden lusture.

Macro structure of flax
The flax is a thick, regular fiber with a subdued lusture. It ranges in length from about 10 cm to 100 cm, averaging about 50 cm. As flax fibers are strand of cells, its thickness depends upon the number of cells in one fiber cross-section. Generally there are three to six cells present in a fiber cross-section. The cells are about 25 mm long. The length to breadth ratio for flax fiber varies from 15000 : 1 to 1500 : 1 for the long and short fibers respectively.

The colour of flax varies from light blonde to grey blond depending upon the agricultural and climatic conditions during growth and the quality of retting.

Polymer system of flax
Chemically flax polymer is composed of cellulose. The degree of polymerisation is about 18000 which means flax polymer is made up of about 18000 cellobiose units. The polymer is about 18000 nm long and about 0.8 nm thick which makes it the longest known, linear textile polymer. These spirals about each other at approximately six degrees to the fiber axis, thereby contributing towards the tenacity and durability of the fiber. The greater crystallinity of flax fibers is demonstrated by the fact that their stronger, crisper and stiffer in handle.

Physical properties of flax
(1) Tenacity - Flax is a very strong fiber because of its highly crystalline structure which permits its long polymers to form more hydrogen bonds than other natural cellulosic fibers. Wet tenacity of flax is considerably higher also.
(2) Elastic plastic nature - Flax is very inelastic because of its highly crystalline polymer system. It tends to lock polymers in to positions with the aid of countless hydrogen bonds which form between the polymers. Hence the polymers cannot yield, and they resist being displaced from their positions in the polymer system.
(3) Thermal properties - Flax has the best heat resistance and conductivity of all the commonly used textile fibres. Unfortunately no satisfactory explanation can be offered for this.