Ramie Fibre
Introduction

The ramie plant Boechmeria Nivea L, is a member of the neetle family and is a shrub with a heavy perennial root stock. This sends numerous short-lived stems which are annual in temperate climate. There are about 200 species, mostly tropical, though several occur north of the Tropic of Cancer in Asia and North America. It is grown in China, Egypt, Australia, Philippines, India, Russia, France, Italy, Spain, West Indies etc. In India its is grown mainly in Assam and West Bengal.

A warm, humid climate with well distributed abundant rainfall throughout the year is ideal for ramie cultivation. Well drained rich sandy loam is the best suited soil for ramie. Lighter soils with fertility and little water-holding capacity are not suitable. Ramie is planted just before monsoon (April - May) so that the whole rainy season can be used for its rapid growth. There is another planting season (September - October) in which frequent irrigation may be necessary.

Harvesting

Harvesting is done when small flower buds begin to appear and the lower leaves of the plant begin to yellow and fall on the ground. At this time, the stalks reach a height of 5-7 feet depending on the soil and the seasonal conditions. After the stems are cut, new shoots grow from the root stalks left in the field. In this way, 2-4 cuttings are obtained in a year. This may be increased to 5-6 cuttings under proper irrigation practices.

Extraction

Being a bast fiber, ramie fiber is obtained from the bark of the stems. However unlike jute, ramie cannot be retted in water to loosen the fibers from the stalks. The fibers have to be separated from the green stems either by manual methods or by machine decorticators. Decortication by hand is practised in China, India and other Asian countries. In India the soft outer tissues of the harvested plants are scrapped off with a bamboo knife or a blunt iron knife and then dried. The dried stems are broken at the bottom and the crude fibers are peeled off from the stalks. The fibers are beaten, washed and dried. Further cleaning is necessary when it is hand spun for making threads. Manual decortication is labourious, expensive and imperfect. Mechanical decortications have solved most of the problems associated with the separation of fibers from the stalks.

Decortication does not completely remove wax and gummy substances adhering to the fibers. These are removed by degumming and the individual fiber strands are separated and the fiber becomes soft and clean. When hand decortication is followed, degumming is done by repeated scrapping, soaking fibers. In another method (chemical degumming) the crude fibers are boiled with a solution of sodium hydroxide along with a soap. Bacteriological degumming method is carried out in large vats in which bacteria containing water is placed. These bacteria attack waxes and gums, leaving cellulose unaffected when the material is under an expert supervision. This method requires considerable time and careful washing.

Ramie Stem

The ramie stem is similar in structure to those of the other bast fibers. The cross section of a young ramie stem shows the following tissues.

1. On the periphery is the epidermis composed of small cells and exhibiting small hairs.
2. Below this is the collenchyma consisting of cells with reinforced at the corners.
3. Next is the parenchyma composed of small cells with inclusions in the form of chlorophyll grains and oxalate crystals.
4. Then follows the inner bark with a few isolated fiber cells recognisable by their thickend wall.
5. Below this is the phloem composed of slender cells.
6. Between the phloem and hylem or the woody part lies the cambium.
7. The central part of the stem is filled with pith.

Ultimate Ramie Fibers

The ultimate ramie fibers vary in length from 1 inch to 12 inches and in diameter from 0.025 to 0.075 mm. So that they have a length breadth ratio of about 3000. The cells usually have a well defined lumen and are thick walled.The orientation of molecules in ramie is extremely regular and the fiber gives an x-ray difraction which is as sharp as that obtained from some micro crystalised material.

Physical properties

Well prepared ramie fibers are silky white and lustrous in appearance. The degree of lustre depends on the method of extraction, degumming and bleaching. Completely degummed fiber is light cream in colour. Snow-White fiber is obtained by suitable bleaching. The moisture content of degummed rammie is 6-8%. Wettability and absorbancy of ramie fiber are of high order. Ramie is very strong and durable, ranking first among all vegetable fibers in this respect. The fiber has a tenacity of 5.3-7.4 gm per denier and a breaking elongation of 1.5-2.4 %. It has three times the strength of hemp and the fibers can be separated almost to the fineness of silk. Ramie is least affected by moisture and has exceptional resistance to micro organisms.

Chemical Composition
Cellulose 68.6 %
Hemicellulose 13.1 %
Pectin 1.9 %
Lignin 0.6 %
Water-Solubles 5.5 %
Fat and Wax 0.3 %
Moisture 10.0 %