close

Вход

Забыли?

вход по аккаунту

код для вставкиСкачать
Resins
David S. Seigler
Department of Plant Biology
University of Illinois
Urbana, Illinois 61801 USA
[email protected]
http://www.life.illinois.edu/seigler
OUTLINE: RESINS AND TURPENTINE
Importance
o Turpentine
o Naval stores
o Adhesives
o Varnishes
Incense
Antiseptics
o Amber
Botanical
Properties
o Lipid soluble
Economics
Isolation
Reading
• CHAPTER 10 IN THE TEXT, p. 257
Introduction
• Resins have played an important role in many
cultures. They are part of paints, incense, and
ship caulking.
• Most have been replaced by synthetic
materials, whereas a few have not been.
• In the plant, resins are actively synthesized
and secreted into specialized canals or ducts.
• Resins are involved in wound responses or in
limiting herbivory to the plants.
• In contrast to gums, resins are insoluble in
water. Most gum plants came from the Old
World; the same thing is true for resin plants,
although a few important ones came from the
New World as well.
• One of the most ancient uses of resins was
as part of incense. Most resins are
hydrocarbon-like and burn.
• Two classical resins used for this purpose
were frankincense (Boswellia carteri,
Burseraceae) and myrrh (Commiphora
myrrha, Burseraceae).
Myrrh, Commiphora aff.
Myrrha, Burseraceae
Courtesy Dr. Dorothea Bedigian
Myrrh, Commiphora aff. myrrha, Burseraceae
S. Colenette. An Illustrated Guide to the Flowers of Saudi Arabia. 1985
Boswellia carteri, Burseraceae
National Geographic
Boswellia carteri, Burseraceae
National Geographic
• The value of these resins in the time of Christ
is illustrated by the fact that the wise men
brought them as gifts along with gold.
• Both plants are native to East Africa
(Ethiopia). They were early products of trade.
They are removed as drops from the trees.
Neither is especially valuable today.
• Many of these resins were also used for
embalming by the Egyptians.
• Other important resins are mastic and
lacquer (not to be confused with liquor) [(or
shellac)].
• Mastic comes from Pistachia lentiscus,
Anacardiaceae. Sometimes used for
chewing gum.
• Lacquer (one kind) comes from Rhus
verniciflua, Anacardiaceae. Both are
used for sealing articles such as wood
carvings. The Chinese and Japanese
made an art form out of use of this type
of finish.
• Many people are highly sensitive to the
Japanese and Chinese ones as that
type of lacquer contains compounds
similar to those in poison ivy.
Copal and dammar
• Copal (from Copaifera or Hymenaea species
and from Agathis, Araucariaceae) are used to
coat art work, e.g., oil paintings. The resin
from Copaifera is sometimes called copaiba
balsam.
• Dammars from members of the family
Dipterocarpaceae (especially Shorea
species) are used in a similar manner.
Aceite, Copaifera
sp., Fabaceae
Hymenaea coubaril,
Fabaceae
T. D. Pennington & J. Sarukhan, Arboles
Tropicales de Mexico, 1968
Shorea robusta,
Dipterocarpaceae
Indian Subcontinent
Trees of Dipterocarpaceae
in Bogor, Indonesia
• Other natural resins are used in adhesives,
soaps, sizing, floor coatings, pharmaceuticals,
fireworks, incense, leather finishes, and
lithography.
• Resins are used in varnishes, but have largely
been replaced by better quality synthetic
materials.
Balsam-of-Peru
• Balsam-of-Peru resin comes from a tree,
Myroxylon balsamum, Fabaceae or
Leguminosae that grows mostly in Central
America. Most of the supply comes from El
Salvador.
• This resin is used for medicinal purposes as
an antiseptic, as a fixative for perfumes and in
soaps.
Balsam-of-Peru, Myroxylon balsamum,
Fabaceae or Leguminosae
• In the old days, it was shipped through the
port of Callao in Peru.
• The tree is about 100 feet tall. The collectors
cut out a small panel from the tree and stuff it
full of rags. Then, they burn and bruise the
tree above the cut open area. Later, they
collect these rags and remove the resin.
Turpentine and rosin
• Turpentine is tapped from a number of trees.
In the U.S., the most important one was Pinus
palustris, the long leaf pine.
• The material obtained is then distilled to
remove the volatile essential oils that are
called "spirits of turpentine".
• These are still used as a solvent, but have
largely been replaced by petroleum- derived
hydrocarbons.
Long leaf pine previously
tapped for terpentine
Terpentine tapping in India
from Pinus species
Courtesy Dr. Ted Hymowitz
• Tapping now often involves application of
plant hormones, sulfuric acid or the herbicide
paraquat to improve yields. The wood is used
after the trees have been tapped extensively,
but is not of as good quality.
• Much turpentine is derived from tall oil from
the paper industry.
• The distillation is now carefully controlled and
done in more sophisticated plants.
• The remaining material (made up
largely of diterpene acids) is called
rosin.
• Rosin is used for violinist bows, for
boxing gloves, and baseball pitchers.
• Rosin is also used in printer's inks,
paper coatings, soaps, varnishes,
sealants, tin can linings, and plywood
manufacture.
• Rosin used to be used to make linoleum. This
material has almost completely been
replaced by vinyl flooring.
• A number of adhesives contain rosin. Others
are purely synthetic.
• The crude material sticks to everything,
including the worker's heels and they used to
be called "tar-heels". The name stuck in North
Carolina.
Naval stores
• Resins from gymnospermous trees
(especially Pinus species) have been used
for millenia to caulk ships. This was done in
Europe and later in the U.S.
• These materials were also used to waterproof
containers of various types in the Old World,
but also by the American Indians.
Amber
• Amber is fossilized rosin. The source in the
temperate areas of the world tends to be
gymnosperms whereas that in the tropics
tends to be legumes. Amber is widely used
for jewelry.
Lac
• Lac used to make shellac is actually an insect
product. The insects live on several trees of
the Fabaceae (Butea, Cajanus, Acacia),
Rhamnaceae (Zizyphus), Sapindaceae
(Schleicheria). The insect (Laccifer lacca) is a
scale insect.
• The reddish translucent material from the
insect (called "seed lac") is treated with
minerals and other resins to make "shellac".
• Shellac is used in high polish interior spirit
varnishes and waxes. Most of it comes from
India.
1/--страниц
Пожаловаться на содержимое документа