Natural rubber is an elastomer An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred when referring to vulcanisates. Each of the monomers (an elastic In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform is removed. The relative amount of deformation is called the strain hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls. Aromatic hydrocarbons , alkanes, alkenes, cycloalkanes and alkyne-based compounds are different types of hydrocarbons polymer A polymer is a large molecule composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a wide variety of properties) that was originally derived from a milky colloidal suspension A colloidal system consists of two separate phases: a dispersed phase and a continuous phase (or dispersion medium). A colloidal system may be solid, liquid, or gaseous, or latex LaTeX is a document markup language and document preparation system for the TeX typesetting program. Within the typesetting system, its name is styled as . The term LaTeX refers only to the language in which documents are written, not to the editor used to write those documents. In order to create a document in LaTeX, a .tex file must be created, found in the sap of some plants. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically. Natural rubber is used extensively in many applications and products, as is synthetic rubber.

Contents

Varieties

The commercial source of natural rubber latex is the Para rubber tree The Pará rubber tree , often simply called rubber tree, is a tree belonging to the family Euphorbiaceae and the most economically important member of the genus Hevea. It is of major economic importance because its sap-like extract (known as latex) can be collected and is the primary source of natural rubber (Hevea brasiliensis), a member of the spurge family, Euphorbiaceae The family is a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti. This is largely because it responds to wounding by producing more latex.

Other plants containing latex include Gutta-Percha Gutta-percha is a genus of tropical trees native to Southeast Asia and northern Australasia, from Taiwan south to the Malay Peninsula and east to the Solomon Islands. It is also an inelastic natural latex produced from the sap of these trees, particularly from the species Palaquium gutta. Chemically, gutta-percha is a polyterpene, a polymer of (Palaquium gutta),[1] rubber fig (Ficus elastica It is a fat bush in the banyan group of figs, growing to 30–40 metres (rarely up to 60 metres/200 feet) tall, with a stout trunk up to 2 metres (6.6 ft) diameter. The trunk develops aerial and buttressing roots to anchor it in the soil and help support heavy branches. It has broad shiny oval leaves 10–35 centimetres (3.9–14 in) long and 5–1), Panama rubber tree (Castilla elastica Castilla elastica, the Panama Rubber Tree, is a tree native to the tropical areas of Mexico, Central America, and northern South America. It was the principal source of latex among the Mesoamerican peoples in pre-Columbian times. The latex gathered from Castilla elastica was converted into usable rubber by mixing the latex sap with the juice of), spurges (Euphorbia Euphorbia is a genus of plants belonging to the family Euphorbiaceae. Consisting of about 2160 species, Euphorbia is one of the most diverse genera in the plant kingdom, maybe exceeded only by Senecio . Members of the family and genus are sometimes referred to as Spurges. Euphorbia antiquorum and Euphorbia serrata are the type species for the spp.), lettuce Lettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold, raw, in salads, sandwiches, hamburgers, tacos, and in many other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as, common dandelion (Taraxacum officinale Taraxacum officinale, commonly called Dandelion, is a herbaceous perennial plant of the family Asteraceae . It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks and shores of water ways, and other areas with moist soils. T. officinale is considered a weedy species, especially in lawns and along), Russian dandelion (Taraxacum Taraxacum is a large genus of flowering plants in the family Asteraceae. They are native to Europe and Asia, and two species, T. officinale and T. erythrospermum, are found as weeds worldwide. Both species are edible in their entirety. Named for their sharp, serrated leaves that resemble lion's teeth. The common name Dandelion (pronounced /ˈdænd kok-saghyz), Scorzonera It comprises about 100 species, the best-known of which is the edible black salsify . Scorzonera tau-saghyz produces rubber (tau-saghyz), and Guayule Parthenium argentatum, commonly known as the Guayule , is a shrub in the family Asteraceae, native to the southwestern United States and northern Mexico, in the US states of New Mexico and Texas; and the Mexican states of Zacatecas, Coahuila, Chihuahua, San Luis Potosí, Nuevo Leon, and Tamaulipas. The plant can be used as an alternate source of (Parthenium argentatum). Although these have not been major sources of rubber, Germany Nazi Germany and the Third Reich are the common English names for Germany under the government of Adolf Hitler and the National Socialist German Worker's Party , from 1933 to 1945. Third Reich (German: Drittes Reich) denotes the Nazi state as the historical successor to the mediæval Holy Roman Empire (962–1806) and to the modern German Empire (1 attempted to use some of these during World War II Albania · Australia · Austria · Azerbaijan · Belarus · Belgium · Brazil · Bulgaria · Burma · Cambodia · Canada · Ceylon (Sri Lanka) · Channel Islands · China · Czechoslovakia · Denmark · Dutch East Indies · Egypt · Estonia · Finland · France · Germany · Gibraltar · Greece · Greenland · Hong Kong · Hungary · Iceland · when it was cut off from rubber supplies[citation needed]. These attempts were later supplanted by the development of synthetic rubbers Synthetic rubber is any type of artificial elastomer, invariably a polymer. An elastomer is a material with the mechanical property that it can undergo much more elastic deformation under stress than most materials and still return to its previous size without permanent deformation. Synthetic rubber serves as a substitute for natural rubber in. To distinguish the tree-obtained version of natural rubber from the synthetic version, the term gum rubber is sometimes used.

Discovery of commercial potential

The para rubber tree initially grew in South America South America is the southern continent of America, situated in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean; North America and the Caribbean Sea lie to the northwest. Charles Marie de La Condamine Charles Marie de La Condamine was a French explorer, geographer, and mathematician is credited with introducing samples of rubber to the Académie Royale des Sciences The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at the forefront of scientific developments in Europe in the 17th and 18th centuries. It is one of the earliest academies of sciences of France France (pronounced /ˈfrænts/ frantss or /ˈfrɑːnts/ frahnts; French pronunciation (help·info): [fʁɑ̃s]), officially the French Republic (French: République française, pronounced: [ʁepyblik fʁɑ̃sɛz]), is a state in Western Europe with several of its overseas territories and islands located on other continents and in the Indian, in 1736.[2] In 1751, he presented a paper by François Fresneau François Fresneau was a French scientist, and is credited for having written the first scientific paper on rubber.He also was known for having the first early idea of water proof material to the Académie (eventually published in 1755) which described many of the properties of rubber. This has been referred to as the first scientific paper on rubber.[2]

When samples of rubber first arrived in England The area now called England has been settled by people of various cultures for about 35,000 years, but it takes its name from the Angles, one of the Germanic tribes who settled during the 5th and 6th centuries. England became a unified state in AD 927, and since the Age of Discovery, which began during the 15th century, has had a significant, it was observed by Joseph Priestley Joseph Priestley (13 March 1733 – 6 February 1804) was an 18th-century English theologian, Dissenting clergyman, natural philosopher, educator, and political theorist who published over 150 works. He is usually credited with the discovery of oxygen, having isolated it in its gaseous state, although Carl Wilhelm Scheele and Antoine Lavoisier also, in 1770, that a piece of the material was extremely good for obliterating pencil A pencil is a writing implement or art medium usually constructed of a narrow, solid pigment core inside a protective casing. The case prevents the core from breaking, and also from marking the user’s hand during use marks on paper, hence the name rubber.

South America remained the main source of the limited amounts of latex rubber that were used during much of the 19th century The 19th century was a period in history marked by the collapse of the Spanish, Portuguese, Chinese, Holy Roman and Mughal empires. This paved the way for the growing influence of the British Empire, the German Empire and the United States, spurring military conflicts but also advances in science and exploration. However in 1876, Henry Wickham Sir Henry Alexander Wickham was a British explorer. He was responsible for stealing about 70,000 seeds from the rubber-bearing tree, Hevea brasiliensis, in the Santarém area of Brazil in 1876. These seeds he accompanied to the Royal Botanic Gardens, Kew, London, from where seedlings were dispatched to Malaysia, Africa, Batavia, and other tropical gathered thousands of para rubber tree seeds from Brazil Brazil (pronounced /brəˈzɪl/ ; Portuguese: Brasil, IPA: [bɾaˈziw]), officially the Federative Republic of Brazil (Portuguese: República Federativa do Brasil, listen (help·info)), is the largest country in South America and the only Portuguese-speaking country in the Americas. It is the world's fifth largest country, both by geographical, and these were germinated in Kew Gardens The Royal Botanic Gardens, Kew, usually referred to simply as Kew Gardens, are 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. The director is Professor Stephen D. Hopper, who succeeded Professor Sir Peter Crane. The Royal Botanic Gardens, Kew is also the name of the organisation that runs, England. The seedlings were then sent to Ceylon Sri Lanka , officially the Democratic Socialist Republic of Sri Lanka and known as Ceylon (/sɪˈlɒn/) before 1972, is an island country in South Asia, located about 31 kilometres (19.3 mi) off the southern coast of India (Sri Lanka Sri Lanka , officially the Democratic Socialist Republic of Sri Lanka and known as Ceylon (/sɪˈlɒn/) before 1972, is an island country in South Asia, located about 31 kilometres (19.3 mi) off the southern coast of India), Indonesia Indonesia , officially the Republic of Indonesia (Indonesian: Republik Indonesia), is a country in Southeast Asia and Oceania. Indonesia comprises 17,508 islands. With a population of around 230 million people, it is the world's fourth most populous country, and has the world's largest population of Muslims. Indonesia is a republic, with an, Singapore Singapore, officially the Republic of Singapore, is an island country off the southern tip of the Malay Peninsula, 137 kilometres north of the equator, in the Southeast Asian region of the Asian continent. It is separated from Malaysia by the Straits of Johor to its north, and from Indonesia's Riau Islands by the Singapore Strait to its south. A and British Malaya British Malaya loosely described a set of states on the Malay Peninsula that were colonized by the British from the 18th and the 19th until the 20th century. Before the formation of Malayan Union in 1946, the colonies were not placed under a single unified administration. Instead, British Malaya comprised the Straits Settlements, the Federated. Malaya (now Malaysia ^ b. The current terminology as per government policy is Bahasa Malaysia but legislation continues to refer to the official language as Bahasa Melayu (literally Malay language). English may continue to be used for some official purposes under the National Language Act 1967) was later to become the biggest producer of rubber. About 100 years ago, the Congo Free State The Congo Free State was a government privately controlled by Leopold II, King of the Belgians through a dummy non-governmental organization, the Association Internationale Africaine. Leopold was the sole shareholder and chairman, who increasingly used it for rubber, copper and other minerals in the upper Lualaba River basin . The state included in Africa Africa is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people (as of 2009, see table) in 61 territories, it accounts for about 14.72% of the world's human population was also a significant source of natural rubber latex, mostly gathered by forced labour Unfree labour is a generic or collective term for those work relations, especially in modern or early modern history, in which people are employed against their will by the threat of destitution, detention, violence (including death), or other extreme hardship to themselves, or to members of their families. Many of these forms of work may be. Liberia Liberia /laɪˈbɪəriə/ , officially the Republic of Liberia, is a country on the west coast of Africa, bordered by Sierra Leone, Guinea, Côte d'Ivoire, and the Atlantic Ocean. As of the 2008 Census, the nation is home to 3,476,608 people and covers 111,369 square kilometres (43,000 sq mi) and Nigeria Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising thirty-six states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in the north. Its coast in the south lies on also started production of rubber.

In India India, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with 1.18 billion people, and the most populous democracy in the world. Mainland India is bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal on the, commercial cultivation of natural rubber was introduced by the British Planters, although the experimental efforts to grow rubber on a commercial scale in India were initiated as early as 1873 at the Botanical Gardens, Calcutta Kolkata ( Kolkata (Bengali: কলকাতা) ; IPA: [ˈkolkat̪a], formerly called Calcutta (help·info)), is the capital of the Indian state of West Bengal. Kolkata is the cultural capital of India and the commercial capital of Eastern India. It is located in eastern India on the east bank of the Hooghly River. The Kolkata metropolitan area. The first commercial Hevea plantations in India were established at Thattekadu in Kerala Kerala (Malayalam: കേരളം, pronounced [Kēraḷam]) is a state in the south-western part of India. It was created on 1 November 1956, with the passing of the States Reorganization Act bringing together the areas where Malayalam is the dominant language in 1902. In the 19th and early 20th century The 20th century of the Common Era began on January 1, 1901 and ended on December 31, 2000. According to the Gregorian calendar, 2000 was the first century leap year since 1600, it was often called "India rubber." Some rubber plantations were also started by the British in Pakistan Pakistan (Urdu pronunciation: [paːkɪsˈtaːn] ( listen)), officially the Islamic Republic of Pakistan (Urdu: اسلامی جمہوریہ پاکِستان), is a country in South Asia. It has a 1,046-kilometre (650 mi) coastline along the Arabian Sea and Gulf of Oman in the south, is bordered by Afghanistan and Iran in the west, and India in the.

Properties

Rubber latex

Rubber exhibits unique physical and chemical properties. Rubber's stress-strain behavior exhibits the Mullins effect The Mullins effect is the stress-strain response in filled rubbers which typically depends on the maximum loading previously encountered. The phenomenon, named for British rubber scientist Leonard Mullins, working at MBL Group in Leyland, can be idealized for many purposes as an instantaneous and irreversible softening of the stress-strain curve, the Payne effect The Payne effect is a particular feature of the stress-strain behaviour of rubber, especially rubber compounds containing fillers such as carbon black. It is named after the British rubber scientist A. R. Payne, who made extensive studies of the effect . The effect is sometimes also known as the Fletcher-Gent effect, after the authors of the first, and is often modeled as hyperelastic. Rubber strain crystallizes.

Owing to the presence of a double bond in each repeat unit, natural rubber is sensitive to ozone cracking.

Solvents

There are two main solvents for rubber: turpentine and naphtha (petroleum). The former has been in use since 1763 when François Fresnau made the discovery. Giovanni Fabronni is credited with the discovery of naphtha as a rubber solvent in 1779. Because rubber does not dissolve easily, the material is finely divided by shredding prior to its immersion.

An ammonia solution can be used to prevent the coagulation of raw latex while it is being transported from its collection site.

Chemical makeup

Latex is a natural polymer of isoprene (most often cis-1,4-polyisoprene) - with a molecular weight of 100,000 to 1,000,000. Typically, a small percent (up to 5% of dry mass) of other materials, such as proteins, fatty acids, resins and inorganic materials (salts) are found in natural rubber. Polyisoprene is also created synthetically, producing what is sometimes referred to as "synthetic natural rubber".

Some natural rubber sources called gutta percha are composed of trans-1,4-polyisoprene, a structural isomer which has similar, but not identical, properties.

Natural rubber is an elastomer and a thermoplastic. However, it should be noted that as the rubber is vulcanized, it will turn into a 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.

Elasticity

In most elastic materials, such as metals used in springs, the elastic behavior is caused by bond distortions. When force is applied, bond lengths deviate from the (minimum energy) equilibrium and strain energy is stored electrostatically. Rubber is often assumed to behave in the same way, but it turns out this is a poor description. Rubber is a curious material because, unlike metals, strain energy is stored thermally. Also, natural rubber is so elastic that when force is applied, on natural rubber when it is on a surface similar to carpet, it may be difficult to 'pull' across the surface. It will stick.

In its relaxed state, rubber consists of long, coiled-up polymer chains that are interlinked at a few points. Between a pair of links, each monomer can rotate freely about its neighbour, thus giving each section of chain leeway to assume a large number of geometries, like a very loose rope attached to a pair of fixed points. At room temperature, rubber stores enough kinetic energy so that each section of chain oscillates chaotically, like the above piece of rope being shaken violently. The entropy model of rubber was developed in 1934 by Werner Kuhn.

When rubber is stretched, the "loose pieces of rope" are taut and thus no longer able to oscillate. Their kinetic energy is given off as excess heat. Therefore, the entropy decreases when going from the relaxed to the stretched state, and it increases during relaxation. This change in entropy can also be explained by the fact that a tight section of chain can fold in fewer ways (W) than a loose section of chain, at a given temperature (nb. entropy is defined as S=k*ln(W)). Relaxation of a stretched rubber band is thus driven by an increase in entropy, and the force experienced is not electrostatic, rather it is a result of the thermal energy of the material being converted to kinetic energy. Rubber relaxation is endothermic, and for this reason the force exerted by a stretched piece of rubber increases with temperature (Metals, for example, become softer as temperature increases). The material undergoes adiabatic cooling during contraction. This property of rubber can easily be verified by holding a stretched rubber band to your lips and relaxing it. Stretching of a rubber band is in some ways equivalent to the compression of an ideal gas, and relaxation is equivalent to its expansion. Note that a compressed gas also exhibits "elastic" properties, for instance inside an inflated car tire. The fact that stretching is equivalent to compression may seem somewhat counter-intuitive, but it makes sense if rubber is viewed as a one-dimensional gas. Stretching reduces the "space" available to each section of chain.

Vulcanization of rubber creates more disulfide bonds between chains, so it shortens each free section of chain. The result is that the chains tighten more quickly for a given length of strain, thereby increasing the elastic force constant and making rubber harder and less extendable.

When cooled below the glass transition temperature, the quasi-fluid chain segments "freeze" into fixed geometries and the rubber abruptly loses its elastic properties, although the process is reversible. This is a property it shares with most elastomers. At very cold temperatures, rubber is actually rather brittle; it will break into shards when struck or stretched. This critical temperature is the reason that winter tires use a softer version of rubber than normal tires. The failing rubber o-ring seals that contributed to the cause of the Challenger disaster were thought to have cooled below their critical temperature. The disaster happened on an unusually cold day.

Current sources

Close to 21 million tons of rubber were produced in 2005 of which around 42% was natural. Since the bulk of the rubber produced is the synthetic variety which is derived from petroleum, the price of even natural rubber is determined to a very large extent by the prevailing global price of crude oil.[citation needed] Today Asia is the main source of natural rubber, accounting for around 94% of output in 2005. The three largest producing countries (Indonesia, Malaysia and Thailand) together account for around 72% of all natural rubber production.

Cultivation

Rubber is generally cultivated in large plantations. See the coconut shell used in collecting latex, in plantations in Kerala, India

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 of the plant is generally well-drained weathered soil consisting of laterite, lateritic types, sedimentary types, nonlateritic red or alluvial soils.

The climatic conditions for optimum growth of Rubber trees consist of (a) Rainfall of around 250 cm evenly distributed without any marked dry season and with at least 100 rainy days per annum (b) Temperature range of about 20°C to 34°C with a monthly mean of 25°C to 28°C (c) High atmospheric humidity of around 80% (d) Bright sunshine amounting to about 2000 hours per annum at the rate of 6 hours per day throughout the year and (e) Absence of strong winds.

Many high-yielding clones have been developed for commercial planting. These clones yield more than 2,000 kilograms of dry Rubber per hectare per annum, when grown under ideal conditions.

Collection

A woman in Sri Lanka in the process of harvesting rubber

In places like Kerala, where coconuts are in abundance, the half shell of coconut is used as the collection container for the latex but glazed pottery or aluminium or plastic cups are more common elsewhere. The cups are supported by a wire that encircles the tree.This wire incorporates a spring so that it can stretch as the tree grows. The latex is led into the cup by a galvanised "spout" that has been 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 alternate or third daily although there are many variations in timing, length and number of cuts. The latex, which contains 25 - 40% dry rubber, is in the bark so the tapper must avoid cutting right through to the wood or the growing cambial layer will be damaged and the renewing bark will be badly deformed making later tapping difficult. It is usual to tap a pannel at least twice, sometimes three times, during the trees' 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 annum. The latex 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 will 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 then start collecting the latex at about midday. Some trees will continue to drip after the collection and this leads to a small amount of cup lump which 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.

The latex will coagulate in cup if kept for long. The latex has to be collected before coagulation. The collected latex is transffered in to coagulation tanks for the preparation of dry rubber or transferred into air tight containers with sieving for ammoniation. Ammoniation is necessary to preserve the latex in colloidal state for long.

Latex is generally processed into either latex concentrate for manufacture of dipped goods or it can be 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 TSR3L or TSRCV or used to produce Ribbed Smoke Sheet grades.

Naturally coagulated rubber (cup lump) is used in the manufacture of TSR10 and TSR20 grade rubbers. The processing of the rubber for these grades is basically a size reduction and cleaning process in order to remove contamination and prepare the material for the final stage drying.

The dried material is then baled and palletized for shipment.

Uses

Compression molded (cured) rubber boots before the flashes are removed

The use of rubber is widespread, ranging from household to industrial products, entering the production stream at the intermediate stage or as final products. Tires and tubes are the largest consumers of rubber. The remaining 44% are taken up by the general rubber goods (GRG) sector, which includes all products except tires and tubes.

Pre-historical uses

The first use of rubber was by the Olmecs, centuries later passed on the knowledge of natural latex from the Hevea Tree in 1600 BC to the Ancient Mayans.[citation needed] They boiled the harvested latex to make a ball for sport.[citation needed]

Manufacturing

Other significant uses of rubber are door and window profiles, hoses, belts, matting, flooring and dampeners (anti-vibration mounts) for the automotive industry in what is known as the "under the bonnet" products. Gloves (medical, household and industrial) and toy balloons are also large consumers of rubber, although the type of rubber used is that of the concentrated latex. Significant tonnage of rubber is used as adhesives in many manufacturing industries and products, although the two most noticeable are the paper and the carpet industry. Rubber is also commonly used to make rubber bands and pencil erasers.

Textile applications

Additionally, rubber produced as a fiber sometimes called elastic, has significant value for use in the textile industry because of its excellent elongation and recovery properties. For these purposes, manufactured rubber fiber is made as either an extruded round fiber or rectangular fibers that are cut into strips from extruded film. Because of its low dye acceptance, feel and appearance, the rubber fiber is either covered by yarn of another fiber or directly woven with other yarns into the fabric. In the early 1900s, for example, 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. Seeking a way to address these shortcomings, the textile industry has turned to Neoprene (polymer form of Chloroprene), a type of synthetic rubber as well as another more commonly used elastomer fiber, spandex (also known as elastane), because of their superiority to rubber in both strength and durability.

Vulcanization

Main article: Vulcanization

Natural rubber is often vulcanized, a process by which the rubber is heated and sulfur, peroxide or bisphenol are added to improve resilience and elasticity, and to prevent it from perishing. Vulcanization greatly improved the durability and utility of rubber from the 1830s on.[citation needed] The development of vulcanization is most closely associated with Charles Goodyear in 1839.[3] Carbon black is often used as an additive to rubber to improve its strength, especially in vehicle tires.

Allergic reactions

Main article: Latex allergy

Some people have a serious latex allergy, and exposure to certain natural rubber latex products such as latex gloves can cause anaphylactic shock. Guayule latex is hypoallergenic and is being researched as a substitute to the allergy-inducing Hevea latexes. Unlike the sappable Hevea tree, these relatively small shrubs must be harvested whole and latex extracted from each cell. Chemical processes may also be employed to reduce the amount of antigenic protein in Hevea latex, resulting in alternative Hevea-based materials such Vytex Natural Rubber Latex that, while not completely hypoallergenic, do provide lessened exposure to latex allergens.

Some allergic reactions are not from the latex but from residues of other ingredients used to process the latex into clothing, gloves, foam, etc. These allergies are usually referred to as multiple chemical sensitivity (MCS).

See also

References

  1. ^ Burns, Bill. "The Gutta Percha Company". History of the Atlantic Cable & Undersea Communications. http://www.atlantic-cable.com/Article/GuttaPercha/. Retrieved 2009-02-14.
  2. ^ a b Untitled Document
  3. ^ Slack, Charles. "Noble Obsession: Charles Goodyear, Thomas Hancock, and the Race to Unlock the Greatest Industrial Secret of the Nineteenth Century". Hyperion 2002. [ISBN 9780786867899]

Hobhouse, Henry (2003, 2005). Seeds of Wealth: Five Plants That Made Men Rich. Shoemaker & Hoard. pp. 125–185. ISBN 1-59376-089-2.

Bibliography

External links

Look up natural rubber in Wiktionary, the free dictionary.
Wikimedia Commons has media related to: Rubber

Categories: Natural materials | Organic polymers | Terpenes and terpenoids | Rubber | Elastomers | Adhesives | Nonwoven fabrics

 

The above information uses material from Wikipedia and is licensed under the GNU Free Documentation License.
Some facts may not have been fully verified for accuracy. [Disclaimers]
This page was last archived by our server on Sun Jul 18 03:21:56 2010. [ refresh local cache ]
Displaying this page or its contents does not use any Wikimedia Foundation's resources.
The owners of this site proudly support the Wikimedia Foundation.

[Hide]▼
'Natural Rubber' News
Will sustain co's margins above 15%: Apollo Tyres - Moneycontrol.com
news.google.com
Will sustain co's margins above 15%: Apollo Tyres

Moneycontrol.com

Raw material as far as rubber is concerned we require a correction in this prices. Today imports of natural rubber coming in landed with duty paid are ...
Google News Search: natural rubber,
Sun Jul 18 03:22:00 2010
'Natural Rubber' Images
Natural Rubber SIR 20 jpg
img.alibaba.com
Natural Rubber SIR 20 jpg
113px x 163px | 11.20kB

[source page]

Natural Rubber SIR 20

Yahoo Images Search: natural rubber,
Sun Jul 18 03:22:00 2010
'Natural Rubber' Blogs
Ulysse Nardin natural rubber over Tokyo
dc2wjrpqck.linkvolume.com
Ulysse Nardin natural rubber over Tokyo

dc2wjrpqck

hu, 01 Jul 2010 11:02:16 GM

Shanghai copper Lundun Tong's guide began to rise; . natural rubber. over Tokyo, Japan,Ulysse Nardin, the world's largest . natural rubber. futures market,AirKing Replica Rolex, futures on the spot guidance to more clearly; fuel often out of ...

Google Blogs Search: natural rubber,
Sun Jul 18 03:22:01 2010
'Natural Rubber' Answers
Are natural latex rubber nipples better or Silicon nipples ?
Q. My daughter is 8 months is it healthy to use the natural latex rubber or is the silicon better?
Asked by Randa - Sat Dec 6 13:59:47 2008 - - 5 Answers - 0 Comments

A. teats??? I was told silicone are more hygienic and last longer, the latex (yellowish ones) go tacky/ sticky when stsrilised a few times. Silicone are better but latex is softer for baby.
Answered by Kitt - Sat Dec 6 15:19:32 2008

Yahoo Answers Search: natural rubber,
Sun Jul 18 03:22:01 2010
[Hide]▲