Fibres
Content
• Fibres-Sources, Definition; Cotton, Jute, Hemp, Flax
Objectives
• At the end of this lecture, student will be able to:
– Discuss the sources of fibres
– Discuss the Pharmacognosy of cotton, jute, hemp, flax
Fibres
Fibres
• Thin, elongated, pointed
Sources
• Plant
: Cotton, Jute, Hemp, Flax
• Animal :
Silk, Wool
• Mineral :
Glass, Asbestos
• Synthetic :
Nylon, Terelyne
Cotton
Synonym
• Raw cotton
• Cotton wool
• Purified cotton
• Absorbent cotton
• Surgical cotton
Source
• Epidermal hairs or trichomes of the seeds of cultivated
species of Gossypium herbaceum and G. barbadense
Family
• Malvaceae
Geograpical source
• USA, Egypt, India
Preparation
• Plant – grown for fibres
• Flowers, fruits- capsules, 2-3 celled, numerous seeds
• Seeds with hairs- Bolls
• Bolls- collected, dried
• Trichomes – collected in ginning press
• Short & long hairs separated from each other
• Longs- cloths
• Shorts (Linters) – Surgical dressings-absorbent cotton
• Raw cotton- wax, fat, colouring matter, veg debris
• Raw cotton – cotton opener- dilute soda solution or soda
ash solution under pressure for 10-15 hrs
• Washed and bleached Bleaching:
Description
• 5 % cholrinated lime for 10-18 hrs
• Washed, very dilute HCl for 4 hrs
• Washed, very dilute HCl for 20 minutes
Cotton
Description
• White, odourless, tasteless, 2.5-5 cm in length, 25 – 32 µ
in dia
Standards
• Staple length: NLT 15mm
• Water soluble extractive: NMT 0.5%
• Sulphated ash: NMT 0.5%
• Should comply with the test for fluorescence, acidity,
adsorbency, oxidizing substances
Constituents
• 90% cellulose, 7-8% moisture, wax, fat, protoplasmic
remains
• Pure cotton- entirely cellulose, 6-7% moisture
Chemical tests
• Ignition test
• Iodine, dry + 80% Sulphuric acid: Purplish blue or bluish
green
• CUOXAM
• Dil NaOH, HCl- insoluble
• Cold 80% Sulphuric acid- dissolves
• 66% Sulphuric acid – insoluble
• Shirlastain A- wash, shades of blue, lilac, purple
• Shirlastain C- Raw- reddish brown, absorbent- pink
• Phloroglucinol + Conc HCl – No pink
• 90% formic acid, 90% phenol, acetone – insoluble
Uses
• Surgical dressings
• Filtering media
• Insulating material
• Absorbs blood, mucus, pus and prevent wound from infections
Flax
Source
• Strands of pericyclic fibres from the stems of linseed
plant, Linum ussitatissimum
Family
• Linaceae
Preparation
• Annual plant, 40-60 cm height
• Flowers blue
Description
• Length 50 cm
• Hygroscopic and takes 20% moisture
• Good conductor of heat
• Have good lustre
Constituents
• Pecto cellulose
Uses
• Lint
• Filtering medium
Tests
• Responds to all reactions under cotton but differ from
cellulose in its behaviour towards certain colouring reagents like fuschine,
cyanine, and methylene blue
Hemp
Source
• Strands of pericyclic fibres from the stems of Cannabis
sativa
Family
• Cannabinnaceae
Preparation
• Rippling, Retting, Heckling
Constituents
• Cellulose, with traces of lignins
Uses
• Ropes, twine, sail cloths
Jute
Source
• Phloem fibres from the plant Corchorus olitorius, C.
capsularis
Family
• Tiliaceae
Preparation
• Rippling, Retting, Heckling; middle lamella destroyed by
oxidising agents
Constituents
• Cellulose, hemicellulose and lignin
Uses
• Splints, filtering and straining media, gunny bags
Summary
• Fibres – thin, elongated pointed
• Fibres – Plant, animal, mineral, synthetic
• Cotton – Gossypium herbaceum, G. barbadense
• Bolls-Linters-raw cotton
• Raw cotton – absorbent cotton
• Surgical dressings
• Flax – pericyclic fibre – cellulose, pectin
• Hemp – pericyclic fibre – cellulose, lignin
• Jute – phloem fibre – cellulose, lignin
• Rippling, Retting and heckling process