2. What is rubber?
• It is a polymeric material
• Characterised by reversible deformation
• Deformation rate depends on the structure and molar mass of the deformed rubber
and on external conditions of the deformation
• It is made up of loosely joined molecules
• Different types of rubber exist but natural rubber has the structure of isoprene
• To be useful as an engineering material there is need to undergo a curing stage
known as Vulcanisation
3. History
• 1600 bc latex extraction from the Hivea tree
• Latex is known as the white blood of the forex
• Initially used by the South Americans
• In 1525, Padre d'Anghieria reported that he had seen Mexican tribes people
playing with elastic balls.
• During 16th century documented the many uses of latex such as waterproofing,
shoes
4. History Rubber Barons
• In the 19th century, towns like Manaus Brazil became the opulent heart of the
rubber trade
• A number of people became rich due to the trade in rubber
• Rubber barons owned large pieces of land, hired armies, enslaved the natives
• The Brazilian rubber market was crushed by the rapid development of the more
efficient rubber plantations of Southeast Asia.
• Latex was shipped to Europe but would be spoilt
• Hot weather rubber cape would be sticky and in cold weather it would harden
• Turpentine was discovered to be useful solvent for rubber and revived its
properties
5. History Production
• In 1815, a humble sawyer - Hancock - invented a rubber mattress and through an
association with MacIntosh he produced the famous waterproof coat known as the
"macintosh".
• 1819 masticator was built Hancock. Here products could be made once rubber was
hot
• 1840 Charles goodyear was still trying to make rubber usefull by hiding it from his
wife
• Finally, in 1842, Hancock came into possession of vulcanized rubber produced by
Goodyear, seeking and finding the secret of vulcanization that brought him a vast
fortune.
6. History Europe and Asia
• in 1876, an English planter, Henry Wickham, collected 70,000 seeds and shipped them to
England.
• About 2800 seeds germinated
• In 1895, Henry Ridley, head of Singapore's botanical garden, persuaded two coffee
growers to plant two acres (.8 ha) of Hevea trees.
• Twelve years later more than 300,000 ha of rubber grew in plantations in Ceylon and
Malaya.
• New innovations increased efficiency, and production doubled every two years.
• Rubber could be produced at only a fraction of the cost of collecting wild rubber in Brazil.
• By 1910, Brazilian production had fallen 50 percent. In 1914, Brazil's market share was
down to around 30 percent, in 1918, to 20 percent, and in 1940 to 1.3 percent.
7. Production Cont …
• In 1845, R.W. Thomson invented the pneumatic tire, the inner tube and even the textured
tread.
• In 1850 rubber toys were being made, as well as solid and hollow balls for golf and tennis.
• The invention of the velocípede by Michaux in 1869 led to the invention of solid rubber,
followed by hollow rubber and finally the re-invention of the tire, because Thomson's
invention had been forgotten.
• Finally, Bouchardt discovered how to polymerize isoprene between 1879 and 1882,
obtaining products with properties similar to rubber.
• The first bicycle tire dates back to 1830, and in 1895 Michelin had the daring idea of
adapting the tire to the automobile. Since then, rubber has held an outstanding position
on the global market.
8. Rubber and World War
• However the Second World War threatened to shift the rubber wealth with Japan
occupying prime rubber-producing areas in Southeast Asia.
• The U.S. feared it would run out of the vital material.
• The Rubber Development Corporation, the chief overseer of rubber acquisition,
sought out other sources including establishing a rubber program.
• The ultimate goal of the program was to establish rubber plantations close to
home.
• Extensive work on synthetic rubber yielded a product that, in time, economists
predicted, would replace natural rubber.
• By 1964 synthetic rubber made up 75 percent of the market.
9. Rubber as an engineering material
• To be useful as an engineering material there is need to undergo a curing stage
known as Vulcanisation
• This requires a crosslinking agents and accelerants
• Vulcanisation leads to the creation of crosslinks in-between molecules
• The rubber obtains unique properties after this stage
• During vulcanization other fillers can be added that assist with the processing of
rubber
10. Rubber ....
• Saturated an unsaturated
• Natural and synthetic
• Polar and non-polar
• Crystallizing and non-crystallizing
• Rubbers for general use – they have properties complying with requirements of more
products, often also with different properties, they are relatively cheap, produced and
consumed in big volume
• Special rubbers – except of basic elastic properties they have at least one special property,
e.g. ageing resistance, resistance against chemicals, resistance against swelling in
non-polar oils, resistance against high or low temperatures. Normally they are produced
and consumed in lower volume than general rubbers and they are significantly more
expensive.
11. NAMING OF RUBBER
• In professional literature and also in practice the rubbers are named besides
commercial names also with abbreviations (in accordance with ASTM-D 1418-76 or
ISO-R 1629).
• Basis for the abbreviation creating is the rubber chemical composition.
• The last letter of appropriate abbreviation characterizes typical atom or group that
is present in the rubber macromolecule.
• Other letters of the abbreviation characterize monomers, the rubber was produced
from.
12. NAMING OF RUBBER
• M – rubbers with saturated hydrocarbon chain of methylene type
• N – rubbers containing nitrogen in polymer chain
• O – rubbers containing oxygen in polymer chain
• Q – rubbers containing oxygen and silicium in polymer chain
• R – rubbers with unsaturated hydrocarbon polymer chain (diene)
• T – rubbers containing sulfur in polymer chain
• U – rubbers containing carbon, oxygen and nitrogen in polymer chain
• Z – rubbers containing phosphor a nitrogen in polymer chain
13. NAMING OF RUBBER
• SBR abbreviation means butadiene-styrene rubber
• CR is chloroprene rubber
• EPM is ethylene-propylene rubber
• EPDM is ethylene propylene diene monomer rubber
• BR is butadiene rubber
• OE-SBR is oil extended styrene-butadiene rubber
• L-SBR means styrene-butadiene rubber produced by polymerization in solution
• H-NBR is hydrogenated acrylonitrile-butadiene rubber
• CIIR is chlorinated isobutene-isoprene rubber
• Natural rubber is marked with abbreviation NR