Natural rubber From Wikipedia, the free encyclopedia
Jump to: navigation navigation,, search "Rubber" redirects here. For other uses, see Rubber see Rubber (disambiguation). (disambiguation). This article is about the polymeric material natural rubber . For man-made rubber materials, see Synthetic rubber .
Latex being collected from a tapped rubber tree Natural rubber is an elastomer elastomer (an (an elastic hydrocarbon hydrocarbon polymer polymer ) that was originally derived from a milky colloidal suspension, suspension, or latex or latex,, found in the sap of some plants. The purified form of natural rubber is the chemical polyisoprene, which can also be produced produc ed synthetically. Natural rubber is used extensively in many applications and products, as is synthetic rubber.
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1 Va Varie rietie tiess 2 Discovery of commerc commercial ial potential 3 Prop Properti erties es 4 So Solve lvent ntss 5 Che Chemica micall mak makeup eup 5.1 Elas Elastic ticity ity o 6 Cur Current rent sources source s 6.1 Cult Cultiva ivatio tion n o 6.2 Coll Collect ection ion o 7 Uses 7.1 Pre-historical uses o 7.2 Man Manufa ufactur cturing ing o 7.3 Textile applications application s o 8 Vul Vulcan caniza ization tion 9 Allergic reactions reaction s 10 Se Seee als also o 11 Ref Referen erences ces
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[ edit edit ] Varieties The major commercial source of natural rubber latex is the Para rubber tree ( Hevea Hevea brasiliensis), brasiliensis), a member of the spurge family, Euphorbiaceae Euphorbiaceae.. This is largely because it responds to wounding by producing more latex. Other plants containing latex include Gutta-Percha ( Palaquium Palaquium gutta), gutta),[1] rubber fig ( Ficus Ficus elastica), elastica elastica), spurges ( Euphorbia spp.), lettuce ), Panama rubber tree (Castilla (Castilla elastica), lettuce,, officinale), Russian dandelion (Taraxacum common dandelion (Taraxacum (Taraxacum officinale), (Taraxacum kok-saghyz ), ), Scorzonera (tau-saghyz), (tau-saghyz), and Guayule ( Parthenium Parthenium argentatum). argentatum). Although these have not been major sources of rubber, Germany attempted to use some of these during World War II when it was cut off from rubber supplies[citation needed ]. These attempts were later supplanted by the development of synthetic of synthetic rubbers. rubbers. To distinguish the tree-obtained version of natural rubber from the synthetic version, the term gum rubber is sometimes used.
[ edit edit ] Discovery of commercial potential Charles Marie de La Condamine is credited with introducing samples of rubber to the Académie Royale des Sciences of France of France in 1736. 1736.[2] In 1751, he presented a paper by François Fresneau to the Académie (eventually published in 1755) which described many
of the properties of rubber. This has been be en referred to as the first scientific paper on [2] rubber. The para rubber tree initially grew in South America, America, and the first European to return to Portugal from Brazil with samples of water-repellent rubberized cloth so shocked people that he was brought to court on the charge of witchcraft.[citation needed ] When samples of rubber first arrived in England England,, it was observed by Joseph Priestley, Priestley, in 1770, that a piece of the material was extremely good for obliterating pencil obliterating pencil 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. However in 1876, Henry Wickham gathered thousands of para rubber tree seeds from Brazil, and these were germinated in Kew Gardens,, UK. The seedlings were then sent to Ceylon (Sri Gardens (Sri Lanka), Lanka), Indonesia Indonesia,, Singapore and British Malaya. Malaya. Malaya (now Malaysia) was later to become the biggest producer of rubber. About 100 years ago, the Congo Free State in Africa was also a significant source of natural rubber latex, mostly gathered by forced labour . Liberia and Nigeria and Nigeria also started production of rubber. In India India,, 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, Kolkata Kolkata.. The first commercial Hevea commercial Hevea plantations in India were established at Thattekadu in Kerala in 1902.
[ edit edit ] Properties
Rubber latex Rubber exhibits unique physical and chemical properties. Rubber's stress-strain behavior exhibits the Mullins effect, effect, the Payne effect, effect, and is often modeled as hyperelastic hyperelastic.. Rubber strain crystallizes. crystallizes. Owing to the presence of a double bond in each repeat unit, unit, natural rubber is sensitive to ozone cracking. cracking.
[ edit edit ] Solvents There are two main solvents for rubber: turpentine and naphtha ( petroleum). 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. 177 9. 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.
[ edit edit ] Chemical makeup Latex is a natural polymer natural polymer of of isoprene 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 as proteins,, fatty acids, 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 isomer which has similar, but not identical, properties. Natural rubber is an elastomer elastomer and and a thermoplastic thermoplastic.. However, it should be noted that as the rubber is vulcanized, it will turn into a thermoset thermoset.. Most rubber in everyday use is vulcanized to a point p oint where it shares properties of both; i.e., if it is heated and cooled, it is degraded but not destroyed.
[edit edit]] Elasticity In most elastic materials, such as metals used in springs 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 electrostatically.. Rubber is often assumed to behave in the same way, but it turns out this is a poor description. d escription. Rubber is a curious material because, unlike metals, strain energy is stored thermally 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, 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. 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 endothermic,, and for this reason the force exerted by a stretched piece of rubber increases 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 gas expansion.. Note that a compressed gas also exhibits "elastic" properties, for instance inside an inflated car tire 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. gas. Stretching reduces the "space" available to each section of chain. Vulcanization of rubber creates more disulfide bonds between 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 of strain,, thereby increasing the elastic force constant and making rubber harder and less extendable. When cooled below the glass transition temperature, 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 rubber o-ring seals that contributed to the cause of the Challenger disaster were disaster were thought to have cooled below their critical temperature. The disaster happened on an unusually cold day.
[ edit edit ] 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.
[edit edit]] Cultivation
Rubber is generally cultivated in large plantations. See the coconut shell used in collecting latex, in plantations in Kerala 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 gen erally well-drained weathered soil consisting of laterite, lateritic types, sedimentary types, nonlateritic red or alluvial soils. The climatic conditions for optimum growth of Rub ber trees consist of (a) Rainfall of around 250 cm evenly ev enly 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. w inds. 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.
[edit edit]] Collection
A woman in Sri Lanka in the process of harvesting rubber In places like Kerala 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 econo mic 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 2 5 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 p reparation
of dry rubber or transferred into air tight containers with sieving for ammoniation. Ammoniation is necessary to preserve the latex in c olloidal state for long. Latex is generally processed into either latex co ncentrate 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.
[ edit edit ] Uses
Compression molded (cured) rubber boots 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 ex cept tires and tubes.
[edit edit]] Pre-historical uses The first use of rubber was natural latex from the Hevea Tree in 1600 160 0 BC by the Ancient [citation needed ] Mayans.. Mayans They boiled the harvested latex to make a ball for sport.[citation needed ]
[edit edit]] 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 toy balloons 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 the paper and the carpet industry. Rubber is also commonly used to make rubber bands and pencil erasers.. erasers
[edit edit]] Textile applications elastic, has significant value Additionally, rubber produced as a fiber sometimes called elastic, 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 to Neoprene (polymer form of Chloroprene of Chloroprene), ), a type of synthetic rubber as well as another ano ther more commonly used elastomer fiber, spandex (also known as elastane), because of their superiority to rubber in both strength and durability.
[ edit edit ] Vulcanization Main article: Vulcanization Natural rubber is often vulcanized vulcanized,, a process by which the rubber is heated and sulfur , peroxide or bisphenol are added to improve resilience and elasticity elasticity,, and to prevent it from perishing 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 Goodyear in 1839.[3] Carbon black is black is often used as an additive to rubber to improve its strength, especially in vehicle tires.
[ edit edit ] Allergic reactions Main article: Latex allergy Some people have a serious latex allergy, 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 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).
[ edit edit ] See also • •
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Akron, Ohio, Ohio, center of the rubber industry Charles Greville Williams, Williams, researched natural rubber being a polymer of the monomer isoprene Elastomer Emulsion dispersion Fordlândia,, failed attempt to establish a rubber plantation in Brazil Fordlândia Guayule,, a useful, non-allergenic alternate source for Hevea Guayule Hevea derived natural rubber, native to North America Ozone cracking Rubber seed oil Resilin,, a rubber substitute Resilin Rubber tapping, tapping, the process of harvesting the rubber sap Rubber technology Stevenson Plan, Plan, historical British plan to stabilize rubber prices Latex,, the main raw material for rubber Latex
[ edit edit ] References Company" . History of the Atlantic Cable & Undersea 1. ^ Burns, Bill. "The Gutta Percha Company". http://www.atlantic-cable.com/Article/GuttaPercha/.. Retrieved 2009Communications. http://www.atlantic-cable.com/Article/GuttaPercha/ 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 978078686789 9780786867899 9] • •
Rubbery Materials and their Compounds by J.A Brydson Rubber Technology by Maurice Morton
Mitsubishi Heavy Industries, Ltd. Technical Review Vol.41 No.1 (Feb. 2004)
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Development of Smar t Polymer Materials and its Various Applications 1. Introduction Polymer materials are applied in various forms in our products such as air conditioning and refrigeration equipments, aircrafts, etc., and Mitsubishi Heavy Industries, Ltd. (MHI) is engaged in product improvement also in terms of materials. We developed the shape memory polymers and the chain curing polymers, which are the unique and
smart materials. And they are expected to be used more widely in various application fields than the field they were initially developed for. . 2-3 Expansion of application By making an effective use of the polymer's function as a temperature sensor, a mechanism was developed to carry out automatic choking in cold season, and was applied to the small-size engines. Further, the polymer was adopted for the handgrips of spoon, toothbrush, razor and kitchen knife by making use of its function of having the shape freely changeable, and then keeping the shape intact. By making use of its property of getting soft at body temperature and outstanding tactile feature, the polymer has come to be applied in medical field as the self-retaining needle for drip (instillation), catheter, catheter, etc. By making use of the temperature change of water vapor permeation, epochal clothing have been successfully developed which keep you warm in cold season and cool in hot season. Study is now under way to apply the FRP (fiber reinforced plastics) where the SMP is used as matrix resin to the inflatable structure in space. This program aims at compact folding of the FRP molded to final shape to transport to the space before expanding it to the original shape in space (Fig. 2). Further, porous foam with similar function is also under development (Fig. 3). filler solution Thermal cation curing
Future Developments of Man-made Fibres D. Entwistle 1 1 Courtaulds Ltd, Coventry
ABSTRACT The growing domination of the whole textile scene by man-made fibres is discussed. There is an industrial and commercial problem of introducing on a large scale a radically new fibre of broadly based textile utility. This is discussed in relation to the great versatility and potential of the existing range of man-made fibres. The significance of the increasing integration of the whole textile industry, from the fibre maker to the garment maker, is discussed and, finally, the new and interesting fibrous structures being introduced are described.
Development of Plastics The first important plastic, celluloid celluloid,, was discovered (c.1869) by the American inventor John W. Hyatt and manufactured by him in 1872; it is a mixture of cellulose nitrate, camphor, and alcohol and is thermoplastic. However, plastics did not come into modern industrial use until after the production (1909) of Bakelite by the American chemist L. H. Baekeland. Bakelite, made by the polymerization of phenol and formaldehyde, is thermosetting. New uses for plastics are continually being discovered. Following World War II optical lenses, artificial eyes, and dentures of acrylic plastics, splints that X rays may pierce, nylon fibers, machine gears, gear s, fabric coatings, wall surfacing, and plastic lamination were developed. More recently a
hydrophilic, or water-attracting, plastic suitable for use in non-irritating contact lenses has been developed. Among the trade names by which many plastic products are widely known are Plexiglas, Lucite, Polaroid, Cellophane, Vinylite, and Koroseal. Plastics reinforced with fiberglass are used for boats, automobile bodies, furniture, and building panels.
plastic plastic, any organic material with the ability to flow into a desired shape when heat
and pressure are applied to it and to retain the shape when they are withdrawn.
Composition and Types of Plastic A plastic is made up principally prin cipally of a binder together with plasticizers, fillers, pigments, and other additives. The binder bin der gives a plastic its main characteristics and usually its name. Thus, polyvinyl chloride is both the name of a binder and the name of a plastic into which it is made. Binders may be natural materials, e.g., cellulose derivatives, casein, or milk protein, but are more commonly synthetic resins. In either case, the binder materials consist of very long chainlike molecules called polymers polymers.. Cellulose derivatives are made from cellulose, a naturally occurring polymer; casein is also a naturally occurring polymer. Synthetic resins are polymerized, or built up, from small simple molecules called monomers. Plasticizers are added to a binder to increase flexibility and toughness. Fillers are added to improve particular properties, e.g., hardness or o r resistance to shock. Pigments are used to impart various colors. Virtually any desired color or shape and many combinations of the properties of hardness, durability, elasticity, and resistance to heat, cold, and acid can be obtained in a plastic. There are two basic ba sic types of plastic: thermosetting, which cannot be resoftened after being subjected to heat and pressure; and thermoplastic, which can be repeatedly softened and remolded by heat and pressure. When heat and pressure are applied to a thermoplastic binder, the chainlike polymers slide past each other, giving the material “plasticity.” However, when heat and pressure are initially applied to a thermosetting binder, the molecular chains become cross-linked, thus preventing any slippage if heat and pressure are reapplied.
See epoxy resins; resins; polyacrylics polyacrylics;; polycarbonates polycarbonates;; polyethylene polyethylene;; polyolefins polyolefins;; polypropylene;; polystyrene polypropylene polystyrene;; polyurethanes polyurethanes;; polyvinyl chloride; chloride; vinyl plastics. plastics.
Environmental Considerations Plastics are so durable that they will not rot or decay as do natural products such as those made of wood. As a result great amounts of discarded plastic products accumulate in the environment as waste. It has been suggested that plastics could be made to decompose slowly when exposed to sunlight by adding certain chemicals to them. Plastics present the additional problem of being difficult to burn. When placed in an incinerator, they tend to melt quickly and flow downward, clogging the incinerator's grate. They also emit harmful fumes; e.g., burning polyvinyl chloride gives off hydrogen chloride gas.
polyvinyl chloride polyvinyl chloride (PVC), thermoplastic that is a polymer of vinyl chloride. Resins
of polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can be made. This plastic pla stic has found extensive use as an electrical e lectrical insulator for wires and cables. Cloth and paper can be coated with it to produce fabrics that may be used for upholstery materials and raincoats. WORKING WITH NATURE As new applications for polymers were being found, some researchers wondered whether they could also play a role in the human body, perhaps in repairing or replacing body tissues and cartilage. The idea was not n ot entirely new. The natural polymer collagen, found in animal connective tissue, had been used as surgeon's thread for more than 2,500 years. And as early as the 1860s, an artificial polymer called collodion, invented a decade earlier by the French chemist Louis Ménard, was used as a liquid dressing for minor wounds. Collodion, made from a solution of cellulose nitrate in alcohol and ether, formed a solid film that could be peeled off after the wound healed. The excellent barrier properties of polymers were also central to an exp eriment in 1933 by Italian biologist Vincenzo Bisceglie, who implanted tumor cells encased in a nitrocellulose membrane in a guinea pig. The cells survived, protected by the membrane against attack by the host animal's immune cells. Meanwhile, the question of contending with the body's immune system was becoming a critical one in medicine. Scientists were beginning to recognize that many diseases of the heart, liver, and kidney actually involved failures of these organs, and they were initiating efforts to replace damaged organs with healthy ones. However, the body's immune cells-which are designed to seek out and destroy any foreign tissue--are unable, for example, to distinguish between an unwanted bacterial infection and a much-desired transplanted
kidney. Although some early drugs, such as a s corticosteroids, azathioprine, and 6mercaptopurine, helped in combating rejection, the problem began to fade only after 1969, when Swiss microbiologist Jean Borel discovered that a soil fungus, cyclosporin A, would selectively interfere with the specific immune cells that drive the rejection reaction. The 1983 approval app roval of cyclosporin A by the U.S. Food and Drug Administration (FDA) gave transplant surgeons a tool that has since saved the lives of thousands of patients with heart, liver, or kidney failure.
Rubber – Properties, Development, Tyres, Tyres, Earthquake Protection Systems and Recycling Topics Covered Background Rubbers Blend of Properties History and Development of Rubber Rubber and Tyres Recycling of Tyres Rubber in Earthquake Protection Systems for Bridges and Buildings Summary
Background With its distinctive tactility and unique smell, rubber is a veritable feast for the senses, providing idiosyncrasy and the potential for design ingenuity in equal measures. Its influence ranges from the practical to the aesthetic, the functional to the fun, and it is finding increasing application in projects characterised by their environmentally-sound objectives, a move that is placing the material at the forefront of contemporary ecofriendly design.
Rubbers Blend of Properties Rubber's physical flexibility seems to be a nod to its amazing versatility. Its durability, elasticity mouldability and waterproof properties have made rubber the material of choice for end users ranging from tyre manufacturers and sportswear designers, to Hollywood special effects creators and fetishists even. Marks and Spencer is in on the rubber scene, having recently used barasol, a type of rubber, as the basis of its new hea d office furniture.
History and Development of Rubber In terms of the material’s history, natural rubber originally derived from the rubber tree (hevea brasiliensis) in South America, and it has been used there for thousands of years. It was only recently that English chemist Joseph Priestly coined the term ‘rubber’ in 1770 upon discovering its erasing capabilities. In the years that followed, while designers could foresee that rubber’s impressive physical properties could be harnessed in terms of possible applications, there remained no way to make it viable for manufacturers. Only in 1839 that Charles Goodyear patented sulphur as a stabilising agent during the processing of rubber, and vulcanisation was born.
Rubber and Tyres In addition to rubber bands and rubber ducks, one of the first things we associate with this material is the humble tyre. Initially invented for tricycles by John Boyd Dunlop in the late 19th century, tyre manufacturing took off in a major way with the invention of the motor car, and commercial rubber production has since gone through the roof. However, in recent years this has caused a major concern for environmental groups.
Recycling of Tyres But while in its natural state the material is biodegradable, the extensive processing that it undergoes (tyres use rubber mixed with synthetic substances such as plastics and chemical curatives to ensure that, when cars reach high speeds, ‘burning rubber’ is a theoretical description rather than a frightening reality) renders rubber much more durable, and is therefore a major recycling problem. One group that is currently attempting to address the threat of endless ‘tyre mountains’ is Earthship, USA. The organisation uses local reclaimed materials to construct environmentally friendly housing that does not use fossil fuels and is completely c ompletely self-sustainable. Earth-rammed tyres are used for the foundations of the housing’s walls, and are then consolidated with w ith straw bale and finally rigid insulation to stabilise the comfort of the interior space. An other company, Remarkable, UK, is adopting a similar attitude to reuse, albeit on a slightly smaller scale. Everything it designs and manufactures from stationery to handbags, comes from identifiable recycled or sustainable resources. The company transforms rubber tyres from having a purely practical original existence to playing an integral part in the aesthetic appeal of a product.
Rubber in Earthquake Protection Systems for Bridges and Buildings Dynamic Isolation Systems (DIS), USA, while not overtly marketing itself as motivated by altruistic environmental concerns, is nonetheless making great use of synthetic rubber’s capacity for extreme longevity, and in do ing so, is helping to ensure that the material it uses will not crowd landfill sites in years to come. The company is responsible for matching earthquake protection systems to the specific n eeds of individual structures,
