Ramie

                                     RAMIE

Egyptian mummies of the pre-dynastic period (5000-3300 n.c.) were wrapped in fabric that has been identified as the bast fibre we now call ramie or China grass.

Botanical Information:-

This fibre comes from plants Boehmeria nivea or Boehmeria tenacissema.

                     

                                                  Ramie

Production and Processing:-

The ramie is a perennial, sending  up many stalks to a height of 1.2-2m (4-6ft). The plants are hardly and grow well in warm climates. They are harvested when the lower stalks turn yellow and the new stalks are beginning to make their appearance.

Decortication:-

The ramie fibers are removed from the stalks by the process of decortications. This is usually out by hand. The process consist in peeling or beating the bark and bast material from the stalks soon after harvesting. The fibers are freed by soaking the bar in water and scraping with knives made from shells, bronze or iron.

The long strands of ramie fibre are then dried and bleached in the sun.

The decortication process varies in detail in different regions. Sometimes the stalks are beaten against rocks before being peeled; the bark is battered with wooden .mallets to free the fibre from adhering woody matter. In Indonesia the" stalks are scraped in such a way as to leave the bast fibres clinging to the woody cores. These are then washed and the fibres are peeled away in the form of long ribbon-like strands.

Degumming:-

Before the ramie fiber can be spun, they must be released from the ribbons or strands in which they are held together by natural gum.

There are many degumming processes in use in different parts of the world. Where fiber production is carried out simply and by hand, the gums are removed by repeated soaking and scraping.

Soda or lime be used if these are available.

Commercial degumming is usually carried out by treating the fibers with caustic soda solution ( less then 1% ) for as long as four hours. The fibers are then treated with bleaching powder, followed by immersion in a bath of dilute acid. The bleaching and acid steeping are repeated until all the gum has been removed. Then the fiber is washed, oiled and dried.

Dyeing:-

Ramie can be dyed with all the classes of dyestuffs used for cotton, including direct, sulphur, basic, azoic and vat dyes. The techniques used are similar and the results are good. Dyeing is level and the fastness to light and washing is comparable with that of the same dyestuffs on cotton.

Structure and Properties:-

Ramie fibre is white and lustrous. Ramie yarns may be as strong as flax line yarns. The fibre is durable but lacks elasticity.

Ramie absorbs water readily. Fabrics made from it will launder easily and dry quickly. They can be dyed readily.

Ramie yarn tends to have a hairy feel, due to the stiffness and coarseness of the fibres, which reduces their cohesion.

The cells of ramie fibre often  45cm (18 in) more than 150 cm (59) long. They are smooth and cylindrical, with thick walls. The surface of the cell is marked by little ridges.

The lumen narrows and disappears towards the ends of the ramie cell, which tapers to a rounded point.

                      

       Ramie

Denier of rami fiber is 4.6-6.4. They are hexagonal and oval in shape.

Physical Properties:-

Specific Gravity    1.51-1.55

Tenacity                6.1g/dtex

Extension               3.8%

Chemical Properties:-

Cellulose                   68.6%

Pectin                         1.9%

Water Soluble         5.5%

Others                        16.4%

Ramie in Use:-

1-    Ramie is made into many types of industrial fabrics, such as canvas and packing materials.

2-    It is an increasing use in upholstery and furnishing and in cloth.

3-    Ramie yarns are used for fishing nets and sewing threads.

4-    The lack of cohesion between ramie fibers and the consequent hairiness of ramie yarn makes it difficult to weave ramie into a smooth fabric. Much of luster lost when it is made into cloth.

This draw back is overcome by mercerization process similar to that used for cotton.

5-    Ramie yarns are maintained under tension and treated with caustic soda. This brings about chemical and physical changes similar to those that take place in cotton.