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Tuesday Lecture – Fibers and Dyes Reading: Textbook, Chapter 15.

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Presentation on theme: "Tuesday Lecture – Fibers and Dyes Reading: Textbook, Chapter 15."— Presentation transcript:

1 Tuesday Lecture – Fibers and Dyes Reading: Textbook, Chapter 15

2 Collect assignments – plant-derived chemicals added to food products

3 Fibers - History Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

4 Fibers - History 10,000 yrs ago – linen (from Linum) in Turkey Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

5 Fibers - History 10,000 yrs ago – linen (from Linum) in Turkey 8,000 yrs ago – fiber sandals in Missouri Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

6 Fibers - History 10,000 yrs ago – linen (from Linum) in Turkey 8,000 yrs ago – fiber sandals in Missouri 7,000 yrs ago – sheep domesticated Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

7 Fibers - History 10,000 yrs ago – linen (from Linum) in Turkey 8,000 yrs ago – fiber sandals in Missouri 7,000 yrs ago – sheep domesticated 5,400 yrs ago – cotton fibers used in Mexico Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

8 Fibers - History 10,000 yrs ago – linen (from Linum) in Turkey 8,000 yrs ago – fiber sandals in Missouri 7,000 yrs ago – sheep domesticated 5,400 yrs ago – cotton fibers used in Mexico 5,000 yrs ago – silk in Asia Use of plant fibers seems to predate that of animal fibers Note: relatively few plants or animals produce fibers that can be woven or spun – use seems fairly recent Fig. 15.1, p. 556

9 Plant vs. Animal Fibers Plant fibers: composed – partly - of cellulose - Animal fibers: composed of protein molecules Fig. 15.2, p. 557

10 Plant vs. Animal Fibers Plant fibers: composed – partly - of cellulose - can be heated - hard to dye - attacked by fungi, mold, termites - less elastic but more absorbent of water Animal fibers: composed of protein molecules - denatured by heat  brittle - Fig. 15.2, p. 557

11 Plant vs. Animal Fibers Plant fibers: composed – partly - of cellulose - can be heated - hard to dye - attacked by fungi, mold, termites - less elastic but more absorbent of water Animal fibers: composed of protein molecules - denatured by heat  brittle - readily accept dyes Fig. 15.2, p. 557

12 Plant vs. Animal Fibers Plant fibers: composed – partly - of cellulose - can be heated - hard to dye - attacked by fungi, mold, termites - less elastic but more absorbent of water Animal fibers: composed of protein molecules - denatured by heat  brittle - readily accept dyes - attacked by moths, silverfish Fig. 15.2, p. 557

13 Plant vs. Animal Fibers Plant fibers: composed – partly - of cellulose - can be heated - hard to dye - attacked by fungi, mold, termites - less elastic but more absorbent of water Animal fibers: composed of protein molecules - denatured by heat  brittle - readily accept dyes - attacked by moths, silverfish - more elastic, less absorbent of water Fig. 15.2, p. 557

14 Classification of Fibers Seed/Fruit Fibers – aid in seed dispersal - cotton, coir, kapok Bast Fibers – from phloem of stem - hemp, jute, ramie, linen Hard Fibers – from leaves of monocots - sisal, henequen, Manila hemp Material % Cellulose Cotton 98 Ramie 86 Hemp 65 Jute 58 Deciduous woods Coniferous woods Cornstalks 43 Wheat straw 42

15 Classification of Fibers Seed/Fruit Fibers – aid in seed dispersal - cotton, coir, kapok Bast Fibers – from phloem of stem - hemp, jute, ramie, linen Hard Fibers – from leaves of monocots - sisal, henequen, Manila hemp Material % Cellulose Cotton 98 Ramie 86 Hemp 65 Jute 58 Deciduous woods Coniferous woods Cornstalks 43 Wheat straw 42

16 Classification of Fibers Seed/Fruit Fibers – aid in seed dispersal - cotton, coir, kapok Bast Fibers – from phloem of stem - hemp, jute, ramie, linen Hard Fibers – from leaves of monocots - sisal, henequen, Manila hemp Material % Cellulose Cotton 98 Ramie 86 Hemp 65 Jute 58 Deciduous woods Coniferous woods Cornstalks 43 Wheat straw 42

17 Fiber Extraction Seed Fibers (Cotton) – actually trichomes, not fibers Ginning – separates fibers from seeds Mostly Bast Fibers: Retting – rots away non-fiber parts Scutching – beat and scraping retted plant material to remove broken pieces of woody matter Hackling – drawing a mass of fibers across pins to separate and align fibers Leaf Fibers Decorticating – crushing plant material and scraping away the nonfibrous material

18 Fiber Extraction Seed Fibers (Cotton) – actually trichomes, not fibers Ginning – separates fibers from seeds Mostly Bast Fibers: Retting – rots away non-fiber parts Scutching – beat and scraping retted plant material to remove broken pieces of woody matter Hackling – drawing a mass of fibers across pins to separate and align fibers Leaf Fibers Decorticating – crushing plant material and scraping away the nonfibrous material

19 Fiber Extraction Seed Fibers (Cotton) – actually trichomes, not fibers Ginning – separates fibers from seeds Mostly Bast Fibers: Retting – rots away non-fiber parts Scutching – beat and scraping retted plant material to remove broken pieces of woody matter Hackling – drawing a mass of fibers across pins to separate and align fibers Leaf Fibers Decorticating – crushing plant material and scraping away the nonfibrous material

20 Seed Fibers - Cotton Fig. 15.7, p. 562

21 Cotton – Ancient History G. barbadense G. hirsutum G. herbaceum G. arboreum Tetraploids AADD Diploids AA 4 independent domestications of cotton Problem: New World domesticates – have one genome present in wild only in Old World Possible resolution: AA genome predates continental separation Fig. 15.9, p. 564

22 Cotton – Ancient History G. barbadense G. hirsutum G. herbaceum G. arboreum Tetraploids AADD Diploids AA 4 independent domestications of cotton Problem: New World domesticates – have one genome present in wild only in Old World Possible resolution: AA genome predates continental separation Fig. 15.9, p. 564

23 Cotton – Ancient History G. barbadense G. hirsutum G. herbaceum G. arboreum Tetraploids AADD Diploids AA 4 independent domestications of cotton Problem: New World domesticates – have one genome present in wild only in Old World Possible resolution: AA genome predates continental separation Fig. 15.9, p. 564

24 Cotton – More Recent History Hand Labor – Associated with Slavery in U.S. Cotton Gin – Enhanced Value Fig , p. 565

25 Cotton - Spinning

26 Cotton - Today Cotton – Issues: Chemical Use Irrigation

27 Cotton Cloth - Details Cleaning – boiling in caustic soda, then treat with hydrogen peroxide  removes pectins, waxes; lightens color of fibers Mercerizing (invented by J. Mercer) – soak thread or textile under pressure in caustic soda  fibers swell, change shape Sizing – add starch or gel to thread, fills in irregularities, strengthens Sanforization – ammonia process, swells fibers and prevents shrinking Permanent press – use chemicals to cross-link cellulose polymers  garment retains shape even after washing

28 Dye Plants Paradox: We associate plants with beautiful colors, yet most plant pigments do not make good dyes

29 Dye Plants Paradox: We associate plants with beautiful colors, yet most plant pigments do not make good dyes Resolution: Most plant pigments are chemically instable – when removed from the environment of the plant cell they are quickly degraded or washed away

30 Dye Plants Paradox: We associate plants with beautiful colors, yet most plant pigments do not make good dyes Resolution: Most plant pigments are chemically instable – when removed from the environment of the plant cell they are quickly degraded or washed away Plant Dyes: - must be chemically stable (many oxidize when exposed to air) - must bind to object being dyed (=fastness) Mordant: chemical that increases adherence of dye to fabric - may also change color of dye

31 Reminder This Thursday, April 21 – class will meet at UT Institute of Agriculture Gardens, next to the Vet School. Dress appropriately to be outside and take a garden tour.


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