PLANT AND SOCIETY ESTELLE LEVETIN KAREN MCMAHON Chapter

PLANT AND SOCIETY ESTELLE LEVETIN & KAREN MCMAHON Chapter 18

CLOTH MAKING • • • Plant fibers Fibers used to wave cloths-Textile fibres Cordage fibers Filling fibres Animal fibres (wool, silk) protein Plant fibres cellulose

• Surface fibres on covering of seed, leaves or fruits • Linen are soft fibres or bast fibres (dicot trees) • Hard fibre from vascular bundles in veins (both xylem and phloem) • Monocot leaves source of hard fibres (Manila Hemp) • Hard fibres have high lignin than soft fibres

Extracting Fibres • Fibres separated from source material through Ginning • Soft fibres extracted from stem through Retting • Degradation of soft tissues through microbial action, leaving tough fibres strand intact and freed • Decortication-Unwanted tissues scraped away by hand or machine for hard fibres

Spinning into yarn • Fibres freed from source then cleaned • Fibres are combined and laid parallel to each other to form a strand • Strand stretched or pulled with fingers and individual strands are twisted together to form thread • Spindle made spinning easier • Rotation of spindle that twists and holds the fibres together forming a yarn

Cotton • Arab introduced cotton to Muslim Spain • Qutn • Top cotton producing country China • United States, India, Pakistan, Egypt, Brazil

THE COTTON PLANT • Most popular natural fiber accounting for half of world’s textiles • Cloth made from seed fibres from Gossypium sp. • Malvaceae • 20 -30 species in genus Gossypium native to parts of Asia, Africa and Central America

• Cotton is shrubby plant with palmately lobed leaves • Most species perennial • Grows best in warm climate • Flower color from white to purple • Fruit is capsule (commercially called ball) when open splits along five seams, revealing white mass of fibres

• In cotton plant, fibres are hairs that extending from seed coat of each of 10 or so seeds in every fruit • 20, 000 seed hairs may grow from single seed • Each cottonseed hair (actually a single seed coat cell) is twisted, hollow strand of cellulose upto 7. 62 cm (3 inches) in length and flattens at maturity

• • • Seed hairs may be Lint or staples (long, slender fibres) Linters (shorter, fuzzy hairs) High quality cotton from longest of lint Purity of cotton cellulose (90 %) and natural twist make cotton excellent fibre for spinning into yarn

SEM Cotton fibers

Cotton Gin • Cotton balls mature 50 -80 days after fertilization • Defoliants sprayed, leaving only bolls for picking • Machine process • Harvested bolls or fibres sent to a gin • During ginning lint is removed from seed

Old and New Varieties of cotton • Commercially new important sp. are G. hirsutum and G. barbadense • G. arboreum and G. herbaceum old varieties

Operation of Cotton Gin

• Saw gin a roller studded with spikes covered by metal mesh • Spikes draw in lint but seeds do not pass through mesh and left behind • Whitney’s Gin separates cotton fibers from seed much quickly • Whitney’s Gin produce 50 pounds (22. 5 kg) of cotton fibres per day

• Cotton seeds source of cottonseed oil • Ginning fibres packed into large bales and graded for quality • Graded bales shipped to yarn or cloth manufacturers • Lint is straightened, sorted into parallel bundles of similar size in preparation for spinning into yarn

Finishing and Sizing • May alter the appearance and modify function of textile • Plant fibres bleached to remove natural color • Bleaching may involve soaking into sour milk or cow’s dung • A bath in buttermilk followed • After washing cloth spread on grass until exposure to sun bleached it white

• Macerization, finishing process improves strength, luster and affinity for dyes • Cotton macerization involves passing cotton through caustic soda (Na. OH) • Permanent press involves shape-retentive finish • Cellulose fibres like cotton wrinkle and crush easily • Chemicals applied that cross-link cellulose fibres giving built-in-memory , shape of garment retained even after laundering, ironing

Bio-engineered Cotton • Bollgard trade name for transgenic cotton • Incorporation of toxin producing genes from Bacillus thurigiensis • Bt toxin effective insecticide against three particularly noxious pest of cotton-cotton bollworm , pink bollworm, tobacco budworm

• Agracetus-biotech company • Working on transgenic cotton plants that combine breathability and feel of cotton cloth with low-maintenance and heatretaining properties of polyester • Created transgenic cotton plant that fill the hollow middle of cellulose seed hairs with small amount of polyester material