Introduction
These fibres are grown as the skin of plant stem.Bast fibres also known as plant fibre or skin fibre,collected from the inner bark like Flax, Ramie, Hemp, Jute etc.
1) Linen Fibre (Flax fibre)
Linen fibre is very oldest and useful fibre obtain from the stalk of flax plant. The hair like fibres, are held together by a gummy substances known as pectin. Linen is composed of 70 % cellulose and 30 % pectin, woody tissue, ash and moisture. Linen is popularly used as a generic term to describe bed, bath, table, and kitchen textiles and furnishing as it was traditionally used for towels, sheets etc.It is very expensive fibres ,grown in small quantities in various parts of the world.
Chemical composition
| Cellulose | 92% |
| Hemicellulose | 2% |
| Lignin | 4% |
| Others | 2% |
Physical characteristics
- This fibre is smooth ,staight and lustrous.
- It is more brittle and less flexible than cotton,so difficult to spin in to yarn.
- It has long staple fibre than cotton
Properties: Linen fibre has number of properties use in home furnishing and apparels.
- Strength-Linen is a durable fibre and it is 2-3 times stronger than cotton fibre.it is second in strength to silk.
- Elasticity-Linen is the least elastic natural fibre.
- Resilience-Linen is quit stiff and wrinkles easily
- Absorbancy-It is excellent for manufacturing towels and handkerchiefs.
- Heat conductivity-Heat conductivity refers to the extent to which heat can be conveyed through a fibre.it is most suitable in summers,as the fibre allows the heat to escape,leaving a cool effect.
Applications(Uses)
Linen fibres are widely used in-
- Apparels
- Home furnishing
- Commercial furnishing
- Upholstery
- Industrial applications.
2) Jute Fibre
Jute is truly one of the most versatile fibres gifted to man nature that fiinds various uses in the form of of handicrafts.Jute is a long, soft, shiny bast fiber that can be spun into coarse, strong threads known as raw material of sacks.
Chemical Composition:
| Cellulose | 65.2% |
| Hemicellulose | 22.2% |
| Lignin | 10.8% |
| Water soluble | 1.5% |
| Fats and wax | 0.3% |
Characteristics
- It is one of the cheapest fibre
- It is second only to cotton in amount produced and variety of uses.
- Jute fibres are composed primarily of the plant material cellulose,lignin and pectin.
Physical Properties
- Specific gravity-1.48
- Moisture-M.R 13.75 & Absobs 35-40 water of its dry weight.
- Strength-Tenacity-dry 3.5-5 g/d wet lower than dry.
- Elasticity-1.8 recovery %
- Specific heat-0.325
- Resiliency-Bad,Abrasion resistance moderate.
- Dimension stability-Good
Chemical Properties
- Acid:Easily damaged by hot dilute or cold concentrated acids.
- Alkalies:Resistance to alkalies
- Organic solvent:Resistance to organic solvents
- Sun light and heat:Poor resistance
- Stains:Poor resistance to water borne stains
- Biological properties:Scoured jute has good resistance to microorganism and insects.
- Heat:Burns rapidly
- Conductivity:Moderate conductor of electricity and heat.
Applications (Uses)
- Use in packing as sacking ,hessian and carpet backing .
- Used in value added applications like upholstery, furnishing, garments and bags etc. due to light weight yarn.
- Jute is chiefly used to make cloth for wrapping bales of raw cotton and to make gunny sacks and gunny cloths.
- These fibres also woven in to curtains, chair covering and carpets.
- Fibres are used alone or blended with other type fibres to make twines and rope.
3) Ramie Fibre
It is a bast fibre, and the fibre used for textiles comes from the inner bark of the vegetative stalks and not the woody stem or outer bark. Ramie is normally harvested two to three times a year, but under good growing conditions can be harvested up to six times per year. Unlike other bast crops, ramie requires chemical processing to de-gum the fibre. Ramie has been grown in china for many centuries, and farmers in ancient China are known to have used the fibre to weave clothing. It may have been used in cloth for wrapping mummies in Egypt. Though ramie and flax are difficult to distinguish in ancient cloth, ramie’s resistance to bacteria and mildew would make it appropriate for mummy wrapping. When the plant being on max fibre content, it is harvested and stem are harvested by cutting by bending the stem or above the roots. This enables the core to be broken and the cortex can be stripped from the plant in situ. Stem are skinned while the plants are fresh and the bark ribbon is dried out to prevent bacteria and fungi.
Fibre Extaction: There are 3 stages of extraction of fibre.
a) Cortex(Bark) is removed-Called decortication.
b) Cortex is scraped to remove most of the outer bark (gums and pectins).
c) Residual cortex material is washed, dried and degummed to extract the spinnable fibre.
Properties
- Ramie fibre has greater strength when wet.
- It is one of the strongest natural fibre.
- Ramie fibre have lack of resiliece .
- It have low elasticity and microscopic appearance.
- This fibre is famous to hold shape,reduce wrinkling and give silky luster to fabric appearance.
- It is similar to Flax fibre in absorbancy,density and microscopic appearance.
- It have high molecular crystallinity that why not dye as well as cotton.
- Ramie is stiff and broken if folded repeatedly in the same place.
Physical and chemical properties
| Cellulose | 68.6 – 76.2% |
| Lignin | 0.6-0.7% |
| Hemicelllose | 13.1-16.7% |
| Pectin | 1.9% |
| Wax | 0.3% |
| Moisture content | 8.0% |
| Density | 1.5g/cm3 |
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