Tuesday Lecture – Fibers and Dyes

Reading: Textbook, Chapter 15

Collect assignments – plant-derived chemicals added to food products

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

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

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

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

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

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

Plant vs. Animal Fibers

Plant fibers: composed – partly - of cellulose

-

Animal fibers: composed of protein molecules

Fig. 15.2, p. 557

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

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

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

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

Classification of FibersSeed/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 hempMaterial % Cellulose

Cotton 98

Ramie 86

Hemp 65

Jute 58

Deciduous woods 41-42

Coniferous woods 41-44

Cornstalks 43

Wheat straw 42

Classification of FibersSeed/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 hempMaterial % Cellulose

Cotton 98

Ramie 86

Hemp 65

Jute 58

Deciduous woods 41-42

Coniferous woods 41-44

Cornstalks 43

Wheat straw 42

Classification of FibersSeed/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 hempMaterial % Cellulose

Cotton 98

Ramie 86

Hemp 65

Jute 58

Deciduous woods 41-42

Coniferous woods 41-44

Cornstalks 43

Wheat straw 42

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

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

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

Seed Fibers - Cotton Fig. 15.7, p. 562

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

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

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

Cotton – More Recent HistoryHand Labor – Associated with Slavery in U.S.

Cotton Gin – Enhanced Value

Fig. 15.11, p. 565

Cotton - Spinning

Cotton - TodayCotton – Issues:

Chemical Use

Irrigation

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

Dye Plants

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

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

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

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.