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Bio334Plnts&Ppl > Latex > Flashcards

Latex Flashcards

1
Q

What is latex? Where is it produced

A
  • Milky emulsion, secondary metabolites
  • Produced by laticifers, special secretory cells
  • Has very different compositions
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2
Q

Where are laticifers found?

A
  • Sporadically in flowering plants
  • Mostly dicots, approx. 20 families
  • Many in Euphorbiaceae, spurge family (poinsettias)
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3
Q

Where does latex form in plant

A
  • Vessels and networks
  • Bark/stem (lettuce)
  • Fruit (fig, papaya)
  • Seed capsule (poppy)
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4
Q

What is the function of latex for the plant?

A
  • Defensive

- Contain numerous different compounds

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5
Q

Rubber

A
  • Latexes w/ elastic properties
  • Long unbranched terpene polymer chain gives flexibility
  • Up to 6000 isoprene units
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6
Q

Where does the name ‘rubber’ come from?

A
  • Discovered that latex, when rubbed on paper, removes pencil marks
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7
Q

Rubber containing plants, where from

A
  • Mostly tropical, over 2000 species

- First used in tropical america, seen by Spanish in 1500’s

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8
Q

What where some of the first human uses of rubber?

A
  • Bouncing ball for Aztec games (Castilla elastic, Moraceae, fig family)
  • Amazonians used for rubber shoes, smoking feet dipped in sap (coagulation by heat made coating waterproof)
  • ‘Rubberizing’ as waterproof coating by Charles Macintosh
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9
Q

‘Rubberizing’

A
  • 1823, Charles Macintosh
  • Dissolve rubber in solvent
  • Water proof coating, called the Macintosh
  • But coating cracked in cold, became sticky in heat
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10
Q

What fixed the problem of ‘Rubberizing’?

A
  • Vulcanization
  • Discovered by Charles Goodyear in 1839
  • Add sulfur w/ heating
  • Adds cross-links to isoprene chain
  • Improved elasticity too
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11
Q

What are the uses of rubber?

A
  • Boots, gloves, electric wire coating, hose, drive belt, tires, etc.
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12
Q

Why is rubber so useful?

A
  • Elastic and waterproof
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13
Q

How much rubber is used for tire manufacturing?

A
  • About 2/3 of total produced rubber

- Not just car tires

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14
Q

When was rubber no longer harvested from the wild?

A
  • 1880
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15
Q

Where does natural rubber mostly come from?

A
  • 98% harvested from Hevea brasiliensis, Euphorbiaceae, spurge family
  • Tree native to Amazonian basin
  • Abundant laticifers in inner bark, high rubber content in latex
  • Tapped from spiral cuts into bark, drip into cup
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16
Q

What did British explorer Wickam do?

A
  • Worked for Kew Gardens
  • Took rubber tree seeds out of Brazil
  • Plantations then established in British, French, and Dutch colonies in SE Asia in late 1800’s
  • 50 million trees by 1910
17
Q

Where is the most modern natural rubber produced?

A
  • SW China and SE Asia
18
Q

What happened to Amazonian plantations of Rubber trees?

A
  • Destroyed by fungal blight
19
Q

What did Henry Ford try to do?

A
  • Massive rubber plantation in Brazil in 1930’s
  • Failed because didn’t use local Brazilian knowledge to grow
  • Succumbed to fungal blight
20
Q

Synthetic Rubber

A
  • Polymers of units similar to isoprene

- Not the same, natural is stronger and more flexible

21
Q

What led to development of synthetic rubber?

A
  • Rubber supply to US cut off in WWII
22
Q

‘High Performance’ use calls for what kind of rubber?

A
  • Natural
23
Q

What percentage of rubber used is from trees?

A
  • 40%
24
Q

How long does it take to get enough latex to make one tire?

A
  • One months drip of latex from 4 trees
25
Q

Possible alternate sources of rubber?

A
  • Guyule, Parthenium argentatum, sunflower family, Asteraceae
26
Q

Guyule plant and how used

A
  • Shrub grows in arid areas
  • Plant that makes Rubber alternative
  • Latex not in laticifers
  • Plant can be mechanically harvested and crushed
  • Latex extracted with solvent
  • Hypo-allergenic
27
Q

What led to the US sanctioned import of rubber to China?

A
  • Korean war 1950-53
28
Q

China’s expansion of rubber growth

A
    • Selected varieties to grow in cooler climes
  • Established state-run plantations
  • plantations bring wealth to people but are environmentally dangerous
29
Q

What is the environmental result of China’s rubber production?

A
  • Expanding into ecologically vulnerable/valuable areas
  • Rubber trees consume large amounts of water
  • Clearing forest for growing rubber increasing in Laos, Myanmar, Cambodia, Vietnam, Thailand, Malaysia, Indonesia
30
Q

Nootkatone

A
  • Fragrant
  • 1st found in Alaska cedar
  • Scent may win fight against ticks, natural insect repellant
31
Q

Ambergris

A
  • Whale vomit, sperm whales

- used to put scents on body b/c allows scent to stick to body longer

32
Q

Why does the skin often feel ‘cool’ when applying scents?

A
  • Because perfumes/aftershaves are often having scent suspended in alcohol
33
Q

What is used to remove ski wax?

A
  • Limonene

Bio334Plnts&Ppl (30 decks)

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