URENA

                                      URENA

           This is a bast fiber that comes from the plant Urena Lobata.

            

                                         Urena

The leaves and flowers are also a famine food in Africa.

Production and Processing:-

The urena plant is a perennial (means grown once in year), with stalks that grow to a height of 3m (10 ft).

 After harvesting, the stalks are retted like jute in ponds or slow streams for 1 - 2 weeks. The fibres are stripped from the retted stalks by hand and washed to remove unwanted material.

Structure and Properties:-

Urena has an attractive handle and appearance. It is near-white when carefully retted, and is soft to the touch. It has a natural lustre.

The fiber has strength similar to that of jute.

Strands of commercial urena are often 1.2m (4 ft) long.

Individual cells of urena are  generally less than 2.6mm (1/10^th in) long. The lumen as in the kenaf cell is usually irreragular.

Urena in Use:-

1-    Unera is made into yarn and fabrics similar to those that are made from jute.

2-    Much of it is used for sacking. 

Sunn

                                  SUNN

The plant Crotalaria juncea has been grown in India and Pakistan since prehistoric times. It is a source of the bast fiber known as sunn.

Production and Processing:-

It grows to the height of 3m ( 10 ft), with stalks nearly 2.5cm (1 in) thick.

 It is cultivated and harvested in India and Bangladash in a manner similar to jute. In 1976, the world production of sunn amounted to about 6,000 tonnes.

Structure and Properties:-

Sunn is a light coloured fiber when carefully prepared. It has a fine luster.

Sunn fiber is almost strong as hemp, and its strenght is greater when wet.

Strands of commerical sunn are some 150cm (5 ft ) long and consist of many individual fibers held together by natural gums.

Individual cells are about 8.5mm ( 1/3 in)long.The cells of sunn fibers are cylinderical, and are marked here and there by joints. The lumen is not so regular as it is in flax, as it is often filled with a yellow substance. Towards the end of the fiber cell, the lumen disappears. The end of the cell are blunt and rounded.

Seen in the cross section, the cells of sunn fiber are oval. There is a comparatively thick coating of lignin surrounding each cell.

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                                            Sunn

Sunn in Use:-

1- Sunn fiber is used for cordage and paper manufacture.

2- It is made into sacking, carpet and rug material.

3-  It has a good resistance to moisture and micro-organisms. It become strong in wet condition and made the fiber particularly useful for fishing nets.

Basic Textile Termenologies

Tensile properties

Tensile properties indicates how a material will react to the forces being applied in Tension. Some tensile properties are given below -

Tenacity

Tenacity is the maximum strength to break a fibre.

Breaking extension

It is expressed in percentage. It is the ratio of elongation at break to the initial length and multiple of hundred.

Work of rupture

The total energy needed or work done to break a fibre.

Initial modulus

Initial modulus is the stress needed to double the length of a fibre.

Yield stress

Yield stress is the stress for which the fibre or material starts yielding.

Work factor

It is the ratio of work of rupture to the product of breaking load and breaking extension.

Elastic recovery

The tendency of a fibre to recover its original size and shape. It is the ratio of elastic extension to total extension.

Flexural properties

It is the property or behaviour shown by the fibre or material when we bend it. The importance of Flexural properties is required when we wear cloth.

Torsional properties

It is the property of fibre or material when a Torsional force is applied on it. Here Torsional force is a twisting force that is applied on the two ends of the material in two opposite direction.

Frictional properties

Frictional properties is due to the friction between the fibres. This properties are shown during processing. Too high friction and too low friction is not good for yarn. Therefore it is an important property when yarn manufacturing and processing.