238
Chapter 13 · Elastomers from Nature! - Polyterpenes
13
application. Balata is obtained from the plant
Mimosups balata, which contains up to 50% resins. In the twentieth century, transmission belts
and golf balls were made from balata. Finally,
there is the rubber chicle, a mixture of cis- and
trans-1,4-polyisoprene in a ratio of 1:3, which is
obtained from the juice of the fruits of the sapodilla tree. The American Thomas Adams mixed
small chicle balls with sugar in 1869 and sold
them as “chewing gum”. The brand name “Chiclets” is still known today.
The trans-1,4-polyisoprene (. Fig. 13.1) also occurs
in nature as plant latex. The trans-1,4-polyisoprene
has different properties than the cis isomer and is
crystalline in its pure form.
Gutta-percha (Malayan: getah percha, rubber tree) is extracted from palaquium trees
(Palaquium oblongifolium), whose latex contains up to 15% resins. In the twentieth century,
gutta-percha, which was obtained in Malaysia
and Indonesia, was used for covering cables, but
was then replaced by synthetic plastics in this
. Fig. 13.3 Mayan ball court with stone ring (© diegograndi/Fotolia)
BOX: How Was Natural Rubber Discovered?
In Europe, natural rubber NR
first became known through
Christopher Columbus at the
beginning of the sixteenth
century. However, it already
had a long history in South
and Central America: The
Aztecs were the first to
produce objects made of NR,
e.g. waterproof rubber shoes,
which were manufactured
in a “dipping process” and
stabilized by smoking. The
Mayas in southern Mexico
used to play with rubber
balls made of NR: On the
Yucatán peninsula, more than
500 ball playgrounds were
discovered. The oldest one
dates back to about 1000 BC.
The Mayan ball game had
little to do with our football
game today: The rubber ball
weighed several kilograms and
was never allowed to touch
the ground. The players of
two teams fighting against
each other had to keep the
ball with shoulders, elbows
or hips always in the air.
At the edge of the playing
field, the “goals”, stone rings
(. Fig. 13.3), through which
the ball had to be struck, were
located at a height of approx.
6 m. The team with the most
goals won the game. The
losing team, or at least their
“captain”, was then sacrificed
to the gods. It is not known
how the players liked to take
over the captain’s armband.
The European history of natural
rubber began in 1736, when
the Frenchman Charles Marie
de La Condamine (1701–1774,
. Fig. 13.4) sent a rubber
sample and a detailed report on
rubber production from a South
American expedition to the Paris
Academy of Sciences. This report
also includes the indigenous
designation of the material:
The rubber was made from a
latex, which was obtained by
scratching the “Hévé” trees, now
known as Hevea brasiliensis. The
Indian words for tree (cao) and
tear (ochu) became today’s word
caoutchouc (“tear of the tree”).
Chapter 13 · Elastomers from Nature! - Polyterpenes
13
application. Balata is obtained from the plant
Mimosups balata, which contains up to 50% resins. In the twentieth century, transmission belts
and golf balls were made from balata. Finally,
there is the rubber chicle, a mixture of cis- and
trans-1,4-polyisoprene in a ratio of 1:3, which is
obtained from the juice of the fruits of the sapodilla tree. The American Thomas Adams mixed
small chicle balls with sugar in 1869 and sold
them as “chewing gum”. The brand name “Chiclets” is still known today.
The trans-1,4-polyisoprene (. Fig. 13.1) also occurs
in nature as plant latex. The trans-1,4-polyisoprene
has different properties than the cis isomer and is
crystalline in its pure form.
Gutta-percha (Malayan: getah percha, rubber tree) is extracted from palaquium trees
(Palaquium oblongifolium), whose latex contains up to 15% resins. In the twentieth century,
gutta-percha, which was obtained in Malaysia
and Indonesia, was used for covering cables, but
was then replaced by synthetic plastics in this
. Fig. 13.3 Mayan ball court with stone ring (© diegograndi/Fotolia)
BOX: How Was Natural Rubber Discovered?
In Europe, natural rubber NR
first became known through
Christopher Columbus at the
beginning of the sixteenth
century. However, it already
had a long history in South
and Central America: The
Aztecs were the first to
produce objects made of NR,
e.g. waterproof rubber shoes,
which were manufactured
in a “dipping process” and
stabilized by smoking. The
Mayas in southern Mexico
used to play with rubber
balls made of NR: On the
Yucatán peninsula, more than
500 ball playgrounds were
discovered. The oldest one
dates back to about 1000 BC.
The Mayan ball game had
little to do with our football
game today: The rubber ball
weighed several kilograms and
was never allowed to touch
the ground. The players of
two teams fighting against
each other had to keep the
ball with shoulders, elbows
or hips always in the air.
At the edge of the playing
field, the “goals”, stone rings
(. Fig. 13.3), through which
the ball had to be struck, were
located at a height of approx.
6 m. The team with the most
goals won the game. The
losing team, or at least their
“captain”, was then sacrificed
to the gods. It is not known
how the players liked to take
over the captain’s armband.
The European history of natural
rubber began in 1736, when
the Frenchman Charles Marie
de La Condamine (1701–1774,
. Fig. 13.4) sent a rubber
sample and a detailed report on
rubber production from a South
American expedition to the Paris
Academy of Sciences. This report
also includes the indigenous
designation of the material:
The rubber was made from a
latex, which was obtained by
scratching the “Hévé” trees, now
known as Hevea brasiliensis. The
Indian words for tree (cao) and
tear (ochu) became today’s word
caoutchouc (“tear of the tree”).