Fibres and its Sources, Pharmacognosy of cotton, jute, hemp, flax Fibres

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 ยต 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

Post a Comment

0 Comments