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Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of
polymer A polymer (; Greek ''poly- Poly, from the Greek :wikt:πολύς, πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong inc ...

polymer
s of the organic compound
isoprene Isoprene, or 2-methyl-1,3-butadiene, is a common with the formula CH2=C(CH3)−CH=CH2. In its pure form it is a colorless volatile liquid. Isoprene is an unsaturated hydrocarbon. It is produced by many plants and animals (including humans) and i ...

isoprene
, with minor impurities of other organic compounds.
Thailand Thailand ( th, ประเทศไทย), historically known as Siam, () officially the Kingdom of Thailand, is a country in Southeast Asia Southeast Asia or Southeastern Asia is the United Nations geoscheme for Asia#South-eastern A ...

Thailand
and
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

Indonesia
are two of the leading rubber producers. Types of
polyisoprene Polyisoprene is a collective name for polymers A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy imag ...

polyisoprene
that are used as natural rubbers are classified as
elastomer An elastomer is a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules, or macromolecules, composed of many Repeat unit, repe ...
s. Currently, rubber is harvested mainly in the form of the latex from the
rubber tree ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant Flowering plants include multiple members of the clade Angiospermae (), commonly called angio ...
(''Hevea brasiliensis'') or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale. Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms, it has a large stretch ratio and high resilience, and also is water-proof. Industrial demand for rubber-like materials began to outstrip natural rubber supplies by the end of the 19th century, leading to the synthesis of
synthetic rubber A synthetic rubber is any artificial elastomer An elastomer is a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules, or mac ...
in 1909 by chemical means.


Varieties


Amazonian rubber tree (''Hevea brasiliensis'')

The major commercial source of natural rubber latex is the Amazonian rubber tree (''
Hevea brasiliensis ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge Family (biology), family Euphorbiaceae. It is the most economically importa ...
''), a member of the
spurge ''Euphorbia'' is a very large and diverse genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. Th ...
family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain the well-being of its members and of society. Ideally, families would off ...
, ''
Euphorbiaceae The Euphorbiaceae, the spurge ''Euphorbia'' is a very large and diverse genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that ...

Euphorbiaceae
''. This species is preferred because it grows well under cultivation. A properly managed tree responds to wounding by producing more latex for several years.


Congo rubber (''Landolphia owariensis'' and ''L. spp.'')

Congo rubber ''Landolphia owariensis'' is a species of liana from the family Apocynaceae found in tropical Africa. Latex can be extracted from this plant for the manufacture of natural rubber. Other names for this vine are eta, the white rubber vine and the Co ...
, formerly a major source of rubber, came from vines in the genus ''
Landolphia ''Landolphia'' is a genus of flowering plants in the family (biology), family Apocynaceae first described as a genus in 1806. They take the form of vines that scramble over host trees. ''Landolphia'' is native to tropical Africa. Characteristics ...
'' ('' L. kirkii'', ''L. heudelotis'', and ''L. owariensis'').


Dandelion

Dandelion ''Taraxacum'' () is a large genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may al ...

Dandelion
milk contains latex. The latex exhibits the same quality as the natural rubber from
rubber trees ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or, most commonly, the rubber tree or rubber plant, is a flowering plant belonging to the spurge Family (biology), family Euphorbiaceae. It is the most economically im ...

rubber trees
. In the wild types of dandelion, latex content is low and varies greatly. In
Nazi Germany Nazi Germany, (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945, was ...

Nazi Germany
, research projects tried to use dandelions as a base for rubber production, but failed. In 2013, by inhibiting one key enzyme and using modern cultivation methods and optimization techniques, scientists in the
Fraunhofer Institute for Molecular Biology and Applied Ecology The Fraunhofer Society (german: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., "Fraunhofer Society for the Advancement of Applied Research") is a German research organization with 72institutes spread throughout Germany, ea ...
(IME) in
Germany Germany (german: Deutschland, ), officially the Federal Republic of Germany, is a country in . It is the in Europe after , and the most populous . Germany is situated between the and seas to the north, and the to the south; it covers an area of ...

Germany
developed a cultivar of the Russian dandelion (''
Taraxacum kok-saghyz ''Taraxacum kok-saghyz'', often abbreviated as TKS and commonly referred to as the Kazakh dandelion, rubber root, or Russian dandelion, is a species of dandelion native to Kazakhstan Kazakhstan,, * russian: Казахстан, Kazakhstan, ...

Taraxacum kok-saghyz
'') that is suitable for commercial production of natural rubber. In collaboration with
Continental Tire A Continental tire or a Continental kit is an upright externally-mounted spare tire located behind an automobile's trunk, made popular by the original Lincoln Continental The Lincoln Continental is a series of Mid-size car , mid-sized and Fu ...
s, IME began a pilot facility.


Other

Many other plants produce forms of latex rich in isoprene polymers, though not all produce usable forms of polymer as easily as the Pará. Some of them require more elaborate processing to produce anything like usable rubber, and most are more difficult to tap. Some produce other desirable materials, for example
gutta-percha Gutta-percha is a tree of the genus '' Palaquium'' in the family Sapotaceae The Sapotaceae are a family In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affin ...
(''
Palaquium gutta ''Palaquium gutta'' is a tree in the family Sapotaceae. The specific name (botany), specific epithet ' is from the Malay language, Malay word ''getah'' meaning "sap or latex". It is known in Indonesia as ''karet oblong''. Description ''Palaquium ...
'') and
chicle Chicle () is a natural gum traditionally used in making chewing gum and other products. It is collected from several species of Meso America, Mesoamerican trees in the genus ''Manilkara'', including ''Manilkara zapota, M. zapota'', ''Manilkara chi ...
from ''
Manilkara ''Manilkara'' is a genus of trees in the family (biology), family Sapotaceae. They are widespread in tropical and semitropical locations, in Africa, Madagascar, Asia, Australia, and Latin America, as well as various islands in the Pacific and in ...

Manilkara
'' species. Others that have been commercially exploited, or at least showed promise as rubber sources, include the rubber fig (''
Ficus elastica ''Ficus elastica'', the rubber fig, rubber bush, rubber tree, rubber plant, or Indian rubber bush, Indian rubber tree, is a species of plant in the ficus, fig genus, native to eastern parts of South Asia and southeast Asia. It has become naturali ...

Ficus elastica
''), Panama rubber tree (''
Castilla elastica ''Castilla elastica'', the Panama rubber tree, is a tree native to the tropical The tropics are the region of Earth surrounding the Equator. They are delimited in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the ...
''), various spurges (''
Euphorbia ''Euphorbia'' is a very large and diverse genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV ...

Euphorbia
'' spp.),
lettuce Lettuce (''Lactuca sativa'') is an annual plant of the daisy family, Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of ...

lettuce
(''
Lactuca ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the daisy family, Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the lettuce, ...
'' species), the related '' Scorzonera tau-saghyz'', various ''
Taraxacum ''Taraxacum'' () is a large of s in the family , which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus is native to Eurasia and North America, but the two most ...

Taraxacum
'' species, including common dandelion (''
Taraxacum officinale ''Taraxacum officinale'', the dandelion or common dandelion, is a flowering Herbaceous plant, herbaceous perennial plant of the Dandelion, dandelion genus in the family Asteraceae (syn. Compositae). The common dandelion is well known for its yell ...

Taraxacum officinale
'') and Russian dandelion, and, perhaps most importantly for its hypoallergenic properties, guayule (''Parthenium argentatum''). The term gum rubber is sometimes applied to the tree-obtained version of natural rubber in order to distinguish it from the synthetic version.Heinz-Hermann Greve "Rubber, 2. Natural" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2000, Wiley-VCH, Weinheim.


History

The first use of rubber was by the indigenous cultures of
Mesoamerica Mesoamerica is a historical and important region In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the ...
. The earliest archeological evidence of the use of natural latex from the ''Hevea'' tree comes from the
Olmec The Olmecs () were the earliest known major Mesoamerica Mesoamerica is a historical and important region In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characterist ...
culture, in which rubber was first used for making balls for the
Mesoamerican ballgame The Mesoamerican ballgame ( nah, ōllamalīztli, , myn, pitz) was a sport with ritual associations played since at least 1650 BC by the pre-Columbian people of Mesoamerica, Ancient Mesoamerica. The sport had different versions in different pl ...
. Rubber was later used by the
Maya Maya may refer to: Civilizations * Maya peoples The Maya peoples () are an ethnolinguistic group of indigenous peoples Indigenous peoples, also referred to as First people, Aboriginal people, Native people, or autochthonous people, are cu ...
and
Aztec The Aztecs () were a Mesoamerican culture that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec peoples included different Indigenous peoples of Mexico, ethnic groups of central Mexico, particularly those g ...

Aztec
cultures – in addition to making balls Aztecs used rubber for other purposes such as making containers and to make textiles waterproof by impregnating them with the latex sap.
Charles Marie de La Condamine#REDIRECT Charles Marie de La Condamine Charles Marie de La Condamine (28 January 1701 – 4 February 1774) was a French explorer Exploration is the act of searching for the purpose of discovery of information Information can be thought ...

Charles Marie de La Condamine
is credited with introducing samples of rubber to the '' Académie Royale des Sciences'' of France in 1736. In 1751, he presented a paper by François Fresneau to the Académie (published in 1755) that described many of rubber's properties. This has been referred to as the first scientific paper on rubber. In England,
Joseph Priestley Joseph Priestley (; 24 March 1733 – 6 February 1804) was an English chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin Medieval Latin was the form of Latin Latin (, or , ) is a cla ...
, in 1770, observed that a piece of the material was extremely good for rubbing off
pencil A pencil is a writing Writing is a medium of human communication that involves the representation of a language with written symbols. Writing systems are not themselves human languages (with the debatable exception of computer language ...

pencil
marks on paper, hence the name "rubber". It slowly made its way around England. In 1764, François Fresnau discovered that
turpentine Turpentine (which is also called gum turpentine, spirit of turpentine, oil of turpentine, wood turpentine, terebenthene, terebinthine and (colloquially) turps) is a fluid obtained by the distillation Distillation, or classical distillation, ...
was a rubber
solvent A solvent (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

solvent
.
Giovanni Fabbroni Giovanni Valentino Mattia Fabbroni (13 February 1752 – 17 December 1822) was an Italian Italian may refer to: * Anything of, from, or related to the country and nation of Italy ** Italians, an ethnic group or simply a citizen of the Italian ...
is credited with the discovery of
naphtha Naphtha ( or ) is a flammable liquid hydrocarbon mixture. Mixtures labelled ''naphtha'' have been produced from natural gas condensate Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon In , a ...
as a rubber solvent in 1779.
Charles Goodyear Charles Goodyear (December 29, 1800 – July 1, 1860) was an American self-taught chemist and manufacturing engineer who developed vulcanized rubber, for which he received patent number 3633 from the United States Patent and Trademark Office, Unit ...

Charles Goodyear
redeveloped
vulcanization Vulcanization (British: Vulcanisation) is a range of processes for hardening rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer (; ...

vulcanization
in 1839, although
Mesoamerican Mesoamerica is a historical and important region In geography Geography (from Ancient Greek, Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...
s had used stabilized rubber for balls and other objects as early as 1600 BC. South America remained the main source of latex rubber used during much of the 19th century. The rubber trade was heavily controlled by business interests but no laws expressly prohibited the export of seeds or plants. In 1876, Henry Wickham smuggled 70,000 Amazonian rubber tree seeds from Brazil and delivered them to
Kew Gardens Kew Gardens is a botanical garden, botanic garden in southwest London that houses the "largest and most diverse botany, botanical and mycology, mycological collections in the world". Founded in 1840, from the exotic garden at Kew Park, its li ...

Kew Gardens
, England. Only 2,400 of these germinated. Seedlings were then sent to
India India, officially the Republic of India (Hindi Hindi (Devanagari: , हिंदी, ISO 15919, ISO: ), or more precisely Modern Standard Hindi (Devanagari: , ISO 15919, ISO: ), is an Indo-Aryan language spoken chiefly in Hindi Belt, ...

India
,
British Ceylon Ceylon (Sinhala Sinhala may refer to: * Something of or related to the Sinhalese people of Sri Lanka * Sinhalese people * Sinhala language, one of the three official languages used in Sri Lanka * Sinhala script, a writing system for the Sinhala ...
(
Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකාව, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon, and officially the Democratic Socialist Republic of Sri Lanka, is ...

Sri Lanka
),
Dutch East Indies The Dutch East Indies (or Netherlands East-Indies; nl, Nederlands(ch)-Indië; ) was a Dutch colony The Dutch colonial empire ( nl, Nederlandse koloniale rijk) comprised the overseas territories and trading posts controlled and administer ...
(
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

Indonesia
),
Singapore Singapore (), officially the Republic of Singapore, is a sovereign state, sovereign island city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

Singapore
, and
British Malaya The term "British Malaya" (; ms, Tanah Melayu British) loosely describes a set of states on the Malay Peninsula The Malay Peninsula (: ''Semenanjung Tanah Melayu'') is a in . The runs approximately north–south and, at its terminus, ...
. Malaya (now
Peninsular Malaysia Peninsular Malaysia (Malay language, Malay: ''Semenanjung Malaysia''), also known as West Malaysia or the Malaysian Peninsula, formerly known as Malaya (disambiguation), Malaya, is the part of Malaysia which occupies the southern half of the Ma ...
) was later to become the biggest producer of rubber. In the early 1900s, the
Congo Free State ''(Work and Progress) , national_anthem = Vers l'avenir ''Vers l'avenir'' (, "Towards the future"), less commonly known by its Dutch language, Dutch title ''Naar wijd en zijd'', is a Belgium, Belgian nationalist song which was also the ...
in Africa was also a significant source of natural rubber latex, mostly gathered by
forced labor Forced labour, or unfree labour, is any work relation, especially in modern history, modern or Early Modern period, early modern history, in which people are employed against their will with the threat of poverty, destitution, detention (impri ...
. King Leopold II's colonial state brutally enforced production quotas. Tactics to enforce the rubber quotas included removing the hands of victims to prove they had been killed. Soldiers often came back from raids with baskets full of chopped-off hands. Villages that resisted were razed to encourage better compliance locally. See
Atrocities in the Congo Free State In the period from 1885 to 1908, many well-documented atrocities were perpetrated in the Congo Free State ''(Work and Progress) , national_anthem = Vers l'avenir , capital = Vivi, Democratic Republic of the Congo, Vivi Boma, Democratic Republ ...
for more information on the rubber trade in the Congo Free State in the late 1800s and early 1900s. In
India India, officially the Republic of India (Hindi Hindi (Devanagari: , हिंदी, ISO 15919, ISO: ), or more precisely Modern Standard Hindi (Devanagari: , ISO 15919, ISO: ), is an Indo-Aryan language spoken chiefly in Hindi Belt, ...

India
, commercial cultivation was introduced by British planters, although the experimental efforts to grow rubber on a commercial scale were initiated as early as 1873 at the
Calcutta Kolkata ( or , ; also known as Calcutta , the official name until 2001) is the capital Capital most commonly refers to: * Capital letter Letter case (or just case) is the distinction between the letters that are in larger upperca ...

Calcutta
Botanical Gardens. The first commercial ''Hevea'' plantations were established at Thattekadu in
Kerala Kerala ( ; ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Kerala
in 1902. In later years the plantation expanded to
Karnataka Karnataka (; ISO The International Organization for Standardization (ISO; ) is an international standard are technical standards developed by international organizations (intergovernmental organizations), such as Codex Alimentarius in f ...

Karnataka
,
Tamil Nadu Tamil Nadu (; ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspape ...

Tamil Nadu
and the
Andaman and Nicobar Islands Andaman and Nicobar Islands is a union territory #REDIRECT Union territory#REDIRECT Union territory A union territory ( hi, script=latn, kendraśāsit pradeś, , centrally administered province) is a type of administrative division Admin ...

Andaman and Nicobar Islands
of India. Today, India is the world's 3rd largest producer and 4th largest consumer of rubber. In Singapore and Malaya, commercial production was heavily promoted by Sir Henry Nicholas Ridley, who served as the first Scientific Director of the
Singapore Botanic Gardens The Singapore Botanic Gardens is a -year-old tropical garden located at the fringe of Singapore's Orchard Road shopping district. It is one of three gardens, and the only tropical garden, to be honoured as a UNESCO World Heritage Site. The Bot ...

Singapore Botanic Gardens
from 1888 to 1911. He distributed rubber seeds to many planters and developed the first technique for tapping trees for latex without causing serious harm to the tree. Because of his fervent promotion of this crop, he is popularly remembered by the nickname "Mad Ridley".


Pre–World War II

Before World War II significant uses included door and window profiles, hoses, belts, gaskets, matting, flooring, and dampeners (antivibration mounts) for the industry. The use of rubber in car
tire A tire (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States ...

tire
s (initially solid rather than pneumatic) in particular consumed a significant amount of rubber.
Gloves A glove is a garment File:KangaSiyu1.jpg, A kanga (African garment), kanga, worn throughout the African Great Lakes region Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fa ...

Gloves
(medical, household, and industrial) and toy
balloon A balloon is a flexible bag that can be inflated with a gas, such as helium Helium (from el, ἥλιος, helios Helios; Homeric Greek: ), Latinized as Helius; Hyperion and Phaethon are also the names of his father and son respectiv ...

balloon
s were large consumers of rubber, although the type of rubber used is concentrated latex. Significant tonnage of rubber was used as
adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantag ...
s in many manufacturing industries and products, although the two most noticeable were the paper and the carpet industries. Rubber was commonly used to make
rubber band A rubber band (also known as an elastic band, gum band or lacky band) is a loop of rubber, usually ring or oval shaped, and commonly used to hold multiple objects together. The rubber band was patented in England on March 17, 1845 by Stephen Pe ...
s and pencil
eraser An eraser (also known as a rubber in Commonwealth A commonwealth is a traditional English term for a political community founded for the common good In philosophy Philosophy (from , ) is the study of general and fundamental que ...

eraser
s. Rubber produced as a fiber, sometimes called 'elastic', had significant value to the textile industry because of its excellent elongation and recovery properties. For these purposes, manufactured rubber fiber was made as either an extruded round fiber or rectangular fibers cut into strips from extruded film. Because of its low dye acceptance, feel and appearance, the rubber fiber was either covered by yarn of another fiber or directly woven with other yarns into the fabric. Rubber yarns were used in foundation garments. While rubber is still used in textile manufacturing, its low tenacity limits its use in lightweight garments because latex lacks resistance to oxidizing agents and is damaged by aging, sunlight, oil and perspiration. The textile industry turned to
neoprene Neoprene (also polychloroprene) is a family of synthetic rubber A synthetic rubber is any artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United ...
(polymer of
chloroprene Chloroprene is the common name for 2-chlorobuta-1,3-diene (IUPAC nomenclature of organic chemistry, IUPAC name) with the chemical formula CH2=CCl−CH=CH2. Chloroprene is a colorless volatile liquid, almost exclusively used as a monomer for the pr ...
), a type of synthetic rubber, as well as another more commonly used elastomer fiber,
spandex Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity (physics), elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Vir ...
(also known as elastane), because of their superiority to rubber in both strength and durability.


Properties

Rubber exhibits unique physical and chemical properties. Rubber's stress–strain behavior exhibits the Mullins effect and the
Payne effect The Payne effect is a particular feature of the stress-strain behaviour of rubber, especially rubber compounds containing Filler (materials), fillers such as carbon black. It is named after the British rubber scientist A. R. Payne, who made exten ...
and is often modeled as hyperelastic. Rubber strain crystallizes. Due to the presence of weakened
allyl An allyl group is a substituent with the structural formula H2C=CH−CH2R, where R is the rest of the molecule. It consists of a methylene bridge (−CH2−) attached to a vinyl group (−CH=CH2). The name is derived from the Latin word for garlic, ...

allyl
ic C-H bonds in each
repeat unit In polymer chemistry, a repeat unit or repeating unit is a part of a polymer whose repetition would produce the complete polymer chain (except for the end-groups) by linking the repeat units together successively along the chain, like the beads of ...
, natural rubber is susceptible to vulcanisation as well as being sensitive to
ozone cracking tubing Cracks can be formed in many different elastomers by ozone Ozone (), or trioxygen, is an inorganic molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chai ...
. The two main
solvent A solvent (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

solvent
s for rubber are
turpentine Turpentine (which is also called gum turpentine, spirit of turpentine, oil of turpentine, wood turpentine, terebenthene, terebinthine and (colloquially) turps) is a fluid obtained by the distillation Distillation, or classical distillation, ...
and
naphtha Naphtha ( or ) is a flammable liquid hydrocarbon mixture. Mixtures labelled ''naphtha'' have been produced from natural gas condensate Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon In , a ...
(petroleum). Because rubber does not dissolve easily, the material is finely divided by shredding prior to its immersion. An
ammonia solution Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia Ammonia is a chemical compound, compound of nitrogen and ...
can be used to prevent the
coagulation Coagulation, also known as clotting, is the process by which blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mech ...

coagulation
of raw latex. Rubber begins to melt at approximately .


Elasticity

On a microscopic scale, relaxed rubber is a disorganized cluster of erratically changing wrinkled chains. In stretched rubber, the chains are almost linear. The restoring force is due to the preponderance of wrinkled conformations over more linear ones. For the quantitative treatment see
ideal chainAn ideal chain (or freely-jointed chain) is the simplest model to describe polymers A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecule File:Pentacene on Ni(111) STM.jpg, ...
, for more examples see
entropic force In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through Spa ...
. Cooling below the
glass transition temperature The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous In condensed matter physics Condensed matter physics is the field of that deals with the macroscopic and microscopic physical propert ...
permits local conformational changes but a reordering is practically impossible because of the larger energy barrier for the concerted movement of longer chains. "Frozen" rubber's elasticity is low and strain results from small changes of
bond Bond or bonds may refer to: Common meanings * Bond (finance) In finance Finance is the study of financial institutions, financial markets and how they operate within the financial system. It is concerned with the creation and management of ...
lengths and angles: this caused the ''Challenger'' disaster, when the American
Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbit A low Earth orbit (LEO) is an Earth-centered orbit near the planet, often specified as having a period Period may refer to: Common uses * Era, a length or span of time * ...

Space Shuttle
's flattened
o-ring An O-ring, also known as a packing or a toric joint, is a mechanical gasket Some seals and gaskets A gasket is a Seal (mechanical), mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage fro ...

o-ring
s failed to relax to fill a widening gap. The glass transition is fast and reversible: the force resumes on heating. The parallel chains of stretched rubber are susceptible to crystallization. This takes some time because turns of twisted chains have to move out of the way of the growing
crystallite A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...

crystallite
s. Crystallization has occurred, for example, when, after days, an inflated toy balloon is found withered at a relatively large remaining volume. Where it is touched, it shrinks because the temperature of the hand is enough to melt the crystals.
Vulcanization Vulcanization (British: Vulcanisation) is a range of processes for hardening rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer (; ...

Vulcanization
of rubber creates
di- Numeral or number prefixes are prefix A prefix is an affix In linguistics Linguistics is the scientific study of language A language is a structured system of communication used by humans, including speech (spoken language), ge ...
and
polysulfide Polysulfides are a class of chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together ...

polysulfide
bonds between chains, which limits the
degrees of freedom Degrees of Freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or other physical ...
and results in chains that tighten more quickly for a given strain, thereby increasing the elastic force constant and making the rubber harder and less extensible.


Malodour

Raw rubber storage depots and rubber processing can produce malodour that is serious enough to become a source of complaints and protest to those living in the vicinity. Microbial impurities originate during the processing of block rubber. These impurities break down during storage or thermal degradation and produce volatile organic compounds. Examination of these compounds using
gas chromatography Gas chromatography (GC) is a common type of chromatography In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (g ...
/
mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio The mass-to-charge ratio (''m''/''Q'') is a physical quantity A physical quantity is a physical property of a material or system that can be Quant ...
(GC/MS) and gas chromatography (GC) indicates that they contain sulfur, ammonia,
alkene In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo dur ...

alkene
s,
ketone In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence i ...
s,
ester An ester is a chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together by chemic ...

ester
s,
hydrogen sulfide Hydrogen sulfide is a chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by havi ...

hydrogen sulfide
, nitrogen, and low-molecular-weight fatty acids (C2–C5). When latex concentrate is produced from rubber, sulfuric acid is used for coagulation. This produces malodourous hydrogen sulfide. The industry can mitigate these bad odours with scrubber systems.


Chemical makeup

Latex is the polymer cis-1,4-polyisoprene – with a
molecular weight A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon ...
of 100,000 to 1,000,000 daltons. Typically, a small percentage (up to 5% of dry mass) of other materials, such as
protein Proteins are large biomolecule , showing alpha helices, represented by ribbons. This poten was the first to have its suckture solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, for which they received a No ...

protein
s,
fatty acid In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
s,
resin In polymer chemistry Polymer chemistry is a sub-discipline of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, stru ...

resin
s, and inorganic materials (salts) are found in natural rubber. Polyisoprene can also be created synthetically, producing what is sometimes referred to as "synthetic natural rubber", but the synthetic and natural routes are distinct. Some natural rubber sources, such as
gutta-percha Gutta-percha is a tree of the genus '' Palaquium'' in the family Sapotaceae The Sapotaceae are a family In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affin ...
, are composed of trans-1,4-polyisoprene, a
structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a chemical compound, compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct chemical bond, bon ...
that has similar properties. Natural rubber is an elastomer and a
thermoplastic A thermoplastic, or thermosoft plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular mass, molecular weight. The polymer ch ...
. Once the rubber is vulcanized, it is a
thermoset A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecule File:Pentacene on Ni(111) STM.jpg, ...

thermoset
. Most rubber in everyday use is vulcanized to a point where it shares properties of both; i.e., if it is heated and cooled, it is degraded but not destroyed. The final properties of a rubber item depend not just on the polymer, but also on modifiers and fillers, such as
carbon black Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of heavy petroleum Petroleum, also known as crude oil and oil, is a naturally occ ...

carbon black
, factice, whiting and others.


Biosynthesis

Rubber particles are formed in the
cytoplasm In cell biology Cell biology (also cellular biology or cytology) is a branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes ...
of specialized latex-producing cells called
laticiferA laticifer is a type of elongated secretory cell found in the leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leave ...
s within rubber plants. Rubber particles are surrounded by a single
phospholipid Phospholipids, also known as phosphatides, are a class of lipid In and , a lipid is a macro that is soluble in solvents. are typically s used to dissolve other naturally occurring hydrocarbon lipid s that do not (or do not easily) disso ...

phospholipid
membrane with
hydrophobic In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence ...
tails pointed inward. The membrane allows biosynthetic proteins to be sequestered at the surface of the growing rubber particle, which allows new monomeric units to be added from outside the biomembrane, but within the lacticifer. The rubber particle is an enzymatically active entity that contains three layers of material, the rubber particle, a biomembrane and free monomeric units. The biomembrane is held tightly to the rubber core due to the high negative charge along the double bonds of the rubber polymer backbone. Free monomeric units and conjugated proteins make up the outer layer. The rubber precursor is
isopentenyl pyrophosphate Isopentenyl pyrophosphate (IPP, isopentenyl diphosphate, or IDP) is an isoprenoid precursor. IPP is an intermediate in the classical, HMG-CoA reductase pathway (commonly called the mevalonate pathway) and in the ''non-mevalonate'' MEP pathway of i ...

isopentenyl pyrophosphate
(an
allylic An allyl group is a substituent with the structural formula H2C=CH−CH2R, where R is the rest of the molecule. It consists of a methylene bridge (−CH2−) attached to a vinyl group (−CH=CH2). The name is derived from the Latin word for garlic, ...

allylic
compound), which elongates by Mg2+-dependent condensation by the action of rubber transferase. The monomer adds to the pyrophosphate end of the growing polymer. The process displaces the terminal high-energy pyrophosphate. The reaction produces a cis polymer. The initiation step is catalyzed by
prenyltransferase Prenyltransferases are a class of enzymes that transfer allylic prenyl groups to acceptor molecules. Prenyl transferases commonly refer to prenyl diphosphate syntheses. Prenyltransferases are commonly divided into two classes, cis (or Z) and trans ...
, which converts three monomers of isopentenyl pyrophosphate into farnesyl pyrophosphate. The farnesyl pyrophosphate can bind to rubber transferase to elongate a new rubber polymer. The required isopentenyl pyrophosphate is obtained from the mevalonate pathway, which derives from acetyl-CoA in the cytosol. In plants, isoprene pyrophosphate can also be obtained from the 1-deox-D-xyulose-5-phosphate/2-C-methyl-D-erythritol-4-phosphate pathway within plasmids. The relative ratio of the farnesyl pyrophosphate initiator unit and isoprenyl pyrophosphate elongation monomer determines the rate of new particle synthesis versus elongation of existing particles. Though rubber is known to be produced by only one enzyme, extracts of latex host numerous small molecular weight proteins with unknown function. The proteins possibly serve as cofactors, as the synthetic rate decreases with complete removal.


Production

More than 28 million tons of rubber were produced in 2017, of which approximately 47% was natural. Since the bulk is synthetic, which is derived from petroleum, the price of natural rubber is determined, to a large extent, by the prevailing global price of crude oil. Asia was the main source of natural rubber, accounting for about 94% of output in 2005. The three largest producers,
Thailand Thailand ( th, ประเทศไทย), historically known as Siam, () officially the Kingdom of Thailand, is a country in Southeast Asia Southeast Asia or Southeastern Asia is the United Nations geoscheme for Asia#South-eastern A ...

Thailand
, Indonesia, and Malaysia, together account for around 72% of all natural rubber production. Natural rubber is not cultivated widely in its native continent of South America due to the existence of South American leaf blight, and other natural predators.


Cultivation

Rubber latex is extracted from rubber trees. The economic life period of rubber trees in plantations is around 32 years, up to 7 years of immature phase and about 25 years of productive phase. The soil requirement is well-drained, weathered soil consisting of laterite, lateritic types, sedimentary types, nonlateritic red or alluvium, alluvial soils. The climatic conditions for optimum growth of rubber trees are: * Rainfall of around evenly distributed without any marked dry season and with at least 100 rainy days per year * Temperature range of about , with a monthly mean of * Atmospheric humidity of around 80% * About 2,000 hours sunshine per year at the rate of six hours per day throughout the year * Absence of strong winds Many high-yielding clones have been developed for commercial planting. These clones yield more than of dry rubber per year, under ideal conditions.


Collection

In places such as Kerala and Sri Lanka, where coconuts are in abundance, the half shell of coconut was used as the latex collection container. Glazed pottery or aluminium or plastic cups became more common in Kerala India, Kerala-India and other countries. The cups are supported by a wire that encircles the tree. This wire incorporates a spring so it can stretch as the tree grows. The latex is led into the cup by a Galvanization, galvanised "spout" knocked into the bark. Tapping normally takes place early in the morning, when the internal pressure of the tree is highest. A good tapper can tap a tree every 20 seconds on a standard half-spiral system, and a common daily "task" size is between 450 and 650 trees. Trees are usually tapped on alternate or third days, although many variations in timing, length and number of cuts are used. "Tappers would make a slash in the bark with a small hatchet. These slanting cuts allowed latex to flow from ducts located on the exterior or the inner layer of bark (cambium) of the tree. Since the cambium controls the growth of the tree, growth stops if it is cut. Thus, rubber tapping demanded accuracy, so that the incisions would not be too many given the size of the tree, or too deep, which could stunt its growth or kill it." It is usual to tap a pannel at least twice, sometimes three times, during the tree's life. The economic life of the tree depends on how well the tapping is carried out, as the critical factor is bark consumption. A standard in Malaysia for alternate daily tapping is 25 cm (vertical) bark consumption per year. The latex-containing tubes in the bark ascend in a spiral to the right. For this reason, tapping cuts usually ascend to the left to cut more tubes. The trees drip latex for about four hours, stopping as latex coagulates naturally on the tapping cut, thus blocking the latex tubes in the bark. Tappers usually rest and have a meal after finishing their tapping work and then start collecting the liquid "field latex" at about midday.


Field coagula

The four types of field coagula are "cuplump", "treelace", "smallholders' lump", and "earth scrap". Each has significantly different properties. Some trees continue to drip after the collection leading to a small amount of "cup lump" that is collected at the next tapping. The latex that coagulates on the cut is also collected as "tree lace". Tree lace and cup lump together account for 10%–20% of the dry rubber produced. Latex that drips onto the ground, "earth scrap", is also collected periodically for processing of low-grade product.


= Cup lump

= Cup lump is the coagulated material found in the collection cup when the tapper next visits the tree to tap it again. It arises from latex clinging to the walls of the cup after the latex was last poured into the bucket, and from late-dripping latex exuded before the latex-carrying vessels of the tree become blocked. It is of higher purity and of greater value than the other three types. 'Cup lumps' can also be used to describe a completely different type of coagulate that has collected in smallholder plantations over a period of 1–2 weeks. After tapping all of the trees, the tapper will return to each tree and stir in some type of acid, which allows the newly harvested latex to mix with the previously coagulated material. The rubber/acid mixture is what gives rubber plantations, markets, and factories a strong odor.


= Tree lace

= Tree lace is the coagulum strip that the tapper peels off the previous cut before making a new cut. It usually has higher copper and manganese contents than cup lump. Both copper and manganese are pro-oxidants and can damage the physical properties of the dry rubber.


= Smallholders' lump

= Smallholders' lump is produced by smallholders, who collect rubber from trees far from the nearest factory. Many Indonesian smallholders, who farm paddies in remote areas, tap dispersed trees on their way to work in the paddy fields and collect the latex (or the coagulated latex) on their way home. As it is often impossible to preserve the latex sufficiently to get it to a factory that processes latex in time for it to be used to make high quality products, and as the latex would anyway have coagulated by the time it reached the factory, the smallholder will coagulate it by any means available, in any container available. Some smallholders use small containers, buckets etc., but often the latex is coagulated in holes in the ground, which are usually lined with plastic sheeting. Acidic materials and fermented fruit juices are used to coagulate the latex — a form of assisted biological coagulation. Little care is taken to exclude twigs, leaves, and even bark from the lumps that are formed, which may also include tree lace.


= Earth scrap

= Earth scrap is material that gathers around the base of the tree. It arises from latex overflowing from the cut and running down the bark, from rain flooding a collection cup containing latex, and from spillage from tappers' buckets during collection. It contains soil and other contaminants, and has variable rubber content, depending on the amount of contaminants. Earth scrap is collected by field workers two or three times a year and may be cleaned in a scrap-washer to recover the rubber, or sold to a contractor who cleans it and recovers the rubber. It is of low quality.


Processing

Latex coagulates in the cups, if kept for long and must be collected before this happens. The collected latex, "field latex", is transferred into coagulation tanks for the preparation of dry rubber or transferred into air-tight containers with sieving for ammoniation. Ammoniation preserves the latex in a colloidal state for longer periods of time. Latex is generally processed into either latex concentrate for manufacture of dipped goods or coagulated under controlled, clean conditions using formic acid. The coagulated latex can then be processed into the higher-grade, technically specified block rubbers such as SVR 3L or SVR CV or used to produce Ribbed Smoke Sheet grades. Naturally coagulated rubber (cup lump) is used in the manufacture of TSR10 and TSR20 grade rubbers. Processing for these grades is a size reduction and cleaning process to remove contamination and prepare the material for the final stage of drying. The dried material is then baled and palletized for storage and shipment.


Vulcanized rubber

Natural rubber is often vulcanized – a process by which the rubber is heated and sulfur, peroxide, or bisphenol are added to improve resistance and elasticity (physics), elasticity and to prevent it from perishing. Carbon black is often used as an additive to rubber to improve its strength, especially in vehicle tires, which account for about 70% (~9 million tons) of carbon black production.


Transportation

Natural rubber latex is shipped from factories in Southeast Asia, South America, and West Africa, West and Central Africa to destinations around the world. As the cost of natural rubber has risen significantly and rubber products are dense, the shipping methods offering the lowest cost per unit weight are preferred. Depending on destination, warehouse availability, and transportation conditions, some methods are preferred by certain buyers. In international trade, latex rubber is mostly shipped in 20-foot ocean containers. Inside the container, smaller containers are used to store the latex.


Rubber shortage

Due to various causes (such as plant disease, climate change, falling commodity price of rubber), there is growing concern for the future supply of rubber.


Uses

Uncured rubber is used for cements; for adhesive, insulating, and friction tapes; and for crepe rubber used in insulating blankets and footwear. Vulcanization, Vulcanized rubber has many more applications. Resistance to abrasion makes softer kinds of rubber valuable for the treads of vehicle tires and conveyor belts, and makes hard rubber valuable for pump housings and piping used in the handling of abrasive sludge. The flexibility of rubber is appealing in hoses, tires and rollers for devices ranging from domestic clothes wringers to printing presses; its elasticity makes it suitable for various kinds of shock absorbers and for specialized machinery mountings designed to reduce vibration. Its relative gas permeation, impermeability makes it useful in the manufacture of articles such as air hoses, balloons, balls and cushions. The permeation, resistance of rubber to water and to the action of most fluid chemicals has led to its use in rainwear, diving gear, and chemical and medicinal tubing and as a lining for storage tanks, processing equipment and railroad tank cars. Because of their electrical resistance and conductance, electrical resistance, soft rubber goods are used as insulation and for protective gloves, shoes, and blankets; Ebonite, hard rubber is used for articles such as telephone housings and parts for radio sets, meters, and other electrical instruments. The coefficient of friction of rubber, which is high on dry surfaces and low on wet surfaces, leads to its use for belt (mechanical), power-transmission belting, highly flexible couplings, and for water-lubricated bearings in deep-well pumps. Indian rubber balls or lacrosse balls are made of rubber. Around 25 million tonnes of rubber are produced each year, of which 30 percent is natural. The remainder is synthetic rubber derived from petrochemical sources. The top end of latex production results in latex products such as surgeons' gloves, balloons, and other relatively high-value products. The mid-range which comes from the technically specified natural rubber materials ends up largely in tires but also in conveyor belts, marine products, windshield wipers, and miscellaneous goods. Natural rubber offers good elasticity, while synthetic materials tend to offer better resistance to environmental factors such as oils, temperature, chemicals, and ultraviolet light. "Cured rubber" is rubber that has been compounded and subjected to the vulcanisation process to create cross-links within the rubber matrix.


Allergic reactions

Some people have a serious latex allergy, and exposure to natural latex rubber products such as latex gloves can cause anaphylactic shock. The antibody generator, antigenic proteins found in ''Hevea'' latex may be deliberately reduced (though not eliminated) through processing. Latex from non-''Hevea'' sources, such as guayule, can be used without allergic reaction by persons with an allergy to ''Hevea'' latex. Some allergic reactions are not to the latex itself, but from residues of chemicals used to accelerate the cross-linking process. Although this may be confused with an allergy to latex, it is distinct from it, typically taking the form of Type IV hypersensitivity in the presence of traces of specific processing chemicals.


Microbial degradation

Natural rubber is susceptible to degradation by a wide range of bacteria. The bacteria ''Streptomyces coelicolor'', ''Pseudomonas citronellolis'', and ''Nocardia'' spp. are capable of degrading vulcanized natural rubber.


See also

* Akron, Ohio, center of the United States rubber industry * Crepe rubber * Ebonite * Emulsion dispersion * Fordlândia, failed attempt to establish a rubber plantation in Brazil * Reinforced rubber * Resilin, a highly elastic protein found in insects * Rubber seed oil * Rubber technology * Stevenson Plan, historical British plan to stabilize rubber prices * Charles Greville Williams, researched natural rubber being a polymer of the monomer isoprene


References


Citations


Sources

* (''1999 Granta edition''). * * * * *


Further reading

*Warren Dean (historian), Dean, Warren. (1997) ''Brazil and the Struggle for Rubber: A Study in Environmental History''. Cambridge University Press. *Grandin, Greg. ''Fordlandia: The Rise and Fall of Henry Ford's Forgotten Jungle City''. Picador Press 2010. *Weinstein, Barbara (1983) ''The Amazon Rubber Boom 1850–1920''. Stanford University Press. *Tully, John A. ''The Devil’s Milk; A Social History of Rubber''. New York: Monthly Review Press, 2011.


External links

* {{Authority control Rubber, Adhesives Crops Forestry in Indonesia Forestry in Malaysia Forestry in Thailand History of forestry Natural materials Non-timber forest products Nonwoven fabrics Organic polymers Terpenes and terpenoids Thermoplastic elastomers