synthetic rubber

File:John Boyd Dunlop (c1915) (cropped).jpg ({{circa|1915}})]]

The expanded use of bicycles, and particularly their pneumatic tires, starting in the 1890s, created increased demand for rubber. In 1909, a team headed by Fritz Hofmann, working at the Bayer laboratory in Elberfeld, Germany, succeeded in polymerizing isoprene, making the first synthetic rubber.{{citation|title=The Moving Powers of Rubber |location=Leverkusen, Germany |publisher=LANXESS AG: 20}}{{cite web|url=http://www.pslc.ws/macrog/exp/rubber/synth/methyl.htm |series=The Story of Rubber |title=Destination Germany: A Poor Substitute|date=2000|first1=Mark |last1=Michalovic}}

Studies published in 1930 written independently by the Russian Sergey Lebedev, the American Wallace Carothers and the German scientist Hermann Staudinger led in 1931 to one of the first successful synthetic rubbers, known as neoprene, which was developed at DuPont under the direction of E. K. Bolton. Neoprene is highly resistant to heat and chemicals such as oil and gasoline, and is used in fuel hoses and as an insulating material in machinery. The company Thiokol applied their name to a competing type of rubber based on ethylene dichloride.{{cite book |last1=Edwards |first1=Douglas C. |editor1-last=Bhowmick |editor1-first=Anil K. |editor2-last=Stephens|editor2-first=Howard |title=Handbook of Elastomers, Second Edition |date=2001 |publisher=Marcel Dekker Inc. |isbn=0-8247-0383-9 |page=135 |chapter=Chap. 5 – Liquid Rubber |edition=First |url=https://books.google.com/books?id=ZFwp_jBu0QsC&q=Handbook+of+Elastomers%2C+Second+Edition+%2B+liquid+elastomers |access-date=8 February 2015}}

In 1935, German chemists synthesized the first of a series of synthetic rubbers known as Buna rubbers. These were copolymers, meaning the polymers were made up from two monomers in alternating sequence. Other brands included Koroseal, which Waldo Semon developed in 1935, and Sovprene, which Soviet researchers created in 1940.Current Biography 1940, "SEMON, WALDO LONSBURY" pp. 723–724

File:Sheet of synthetic rubber coming off the rolling mill at the plant of Goodrich.jpg (1941)]]

File:"WATCH FOR THESE MARKS" - NARA - 516054.jpg

Production of synthetic rubber in the United States expanded greatly during World War II since the Axis powers controlled nearly all the world's limited supplies of natural rubber by mid-1942, following the Japanese conquest of most of Asia, particularly in the Southeast Asian colonies of British Malaya (now Malaysia) and the Dutch East Indies (now Indonesia) from where much of the global supply of natural rubber was sourced.{{cite book |last1=Gropman |first1=Alan L. |title=Mobilizing U. S. Industry in World War II |date=1996 |publisher=Institute for National Strategic Studies |isbn=0788136461 |page=115}}

Operation Pointblank bombing targets of Nazi Germany included the Schkopau (50,000 tons/yr) plant and the Hüls synthetic rubber plant near Recklinghausen (30,000, 17%),{{Citation |last=Stormont |first=John W. |date=March 1946 |title=AAFRH-19: The Combined Bomber Offensive; April through December 1943 |location=Dwight D. Eisenhower Presidential Library: Collection of 20th Century Military Records, 1918–1950 Series I: Historical Studies Box 35 |publisher=AAF Historical Office; Headquarters, Army Air Force |pages=74–5, 81 |quote=SECRET ... Classification Cancelled ... JUN 10 1959 |orig-year=summer of 1945 | postscript =.}} and the Kölnische Gummifäden Fabrik tire and tube plant at Deutz on the east bank of the Rhine.{{Citation |last=Gurney |first=Gene |year=1962 |title=The War in the Air: a pictorial history of World War II Air Forces in combat |location=New York |publisher=Bonanza Books |pages=215}} The Ferrara, Italy, synthetic rubber factory (near a river bridge) was bombed August 23, 1944.{{Cite web|url=http://usaaf.net/chron/44/aug44.htm|archive-url=https://web.archive.org/web/20090211103512/http://usaaf.net/chron/44/aug44.htm|archive-date=11 February 2009|title=Army Air Forces in World War II|date=February 11, 2009}} Three other synthetic rubber facilities were at Ludwigshafen/Oppau (15,000), Hanover/Limmer (reclamation, 20,000), and Leverkusen (5,000). A synthetic rubber plant at Oświęcim, in Nazi-occupied Poland, was under construction on March 5, 1944{{citation |last=Williamson |first=Charles C. |others=Hughes, R. D.; Cabell, C. P.;Nazarro, J. J.; Bender, F. P.; & Crigglesworth, W. J. |date=5 March 1944 |title=Plan for Completion of Combined Bomber Offensive (Appendices C & F) |location=Dwight D. Eisenhower Presidential Library: SMITH, WALTER BEDELL: Collection of World War II Documents, 1941–1945; Box No.: 48 |publisher=HQ, U.S.S.T.A.F | quote=DECLASSIFIED ... 4/24/74}} operated by IG Farben and supplied with slave labor, by the SS, from the associated camp Auschwitz III (Monowitz).{{cite book|first=Sybille|last=Steinbacher|translator-first=Shaun|translator-last=Whiteside|title=Auschwitz: a history|date=2005|publisher=Ecco|location=New York|isbn=978-0060825812|page=45|edition=1st Ecco|url-access=registration|url=https://archive.org/details/auschwitzhistory00stei/page/45}}{{cite book| first1=Vernon|last1=Herbert|first2=Attilio|last2=Bisio|title=Synthetic Rubber: A Project That Had to Succeed|series=Contributions in Economics and Economic History|publisher= Greenwood Press|date=December 11, 1985|isbn=978-0313246340|page=32ff}}

The most prevalent synthetic rubber is styrene-butadiene rubbers (SBR) derived from the copolymerization of styrene and 1,3-butadiene. Other synthetic rubbers include:

• polyisoprene, prepared by polymerization of isoprene
• neoprene, prepared by polymerization of 2-chlorobutadiene
• nitrile rubber made from cyanobutadiene or 2-propenenitrile and butadiene

Many variations of these can be prepared with mixtures of monomers and with various catalysts that allow for control of stereochemistry.{{Ullmann| doi=10.1002/14356007.a23_221 |isbn=3527306730| title=Rubber, 1. Survey| year=2000| last1=Greve| first1=Heinz-Hermann| last2=Threadingham| first2=Desmond}}

Polyisobutylene or butyl rubber is commonly used in tire inner tubes or linings because of its resistance to diffusion of air through the lining. It is a much less resilient material than cis-polybutadiene which is frequently used in tire sidewalls to minimize energy losses and heat build-up. It is so resilient that it is used in super balls. An elastomer widely used for external sheet such as roof coverings is Hypalon or chlorosulphonated polyethylene. Synthetic rubbers like EPR can also be used for electrical insulation.

{{main|Silicone rubber}}

Silicone rubber is also a synthetic elastomer composed of silicone polymers. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers are often one- or two-part polymers, and may contain fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures.

File:RubberSyn&Natural.png, the main constituent of natural rubber. Synthetic cis-polyisoprene and natural cis-polyisoprene are derived from different precursors by different chemical pathways.]]

Natural rubber, coming from latex of Hevea brasiliensis, is mainly poly-cis-isoprene.

Synthetic rubber, like most other polymers, is made from various petroleum-based monomers.

Some synthetic rubbers are less sensitive to ozone cracking than natural rubber. Natural rubber is sensitive because of the double bonds in its chain structure, but some synthetic rubbers do not possess these bonds and so are more resistant to ozone cracking. Examples include Viton rubber, ethylene propylene diene monomer (EPDM), and butyl rubber.

A new class of synthetic rubber is the thermoplastic elastomers which can be moulded easily unlike conventional natural rubber vulcanized rubber. Their structure is stabilized by cross-linking by crystallites in the case of polyurethanes or by amorphous domains in the case of SBS block copolymers.

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Category:Rubber

Category:Organic polymers

Category:Polymer structural groups

Category:Elastomers

Category:U.S. Synthetic Rubber Program

Category:Rubber industry