CMG INTERNATIONAL TRADING DALIAN CO. ,mainly in regard of foreign trade of rubber machinery,manages all kinds of rubber machinery&equipment such as rubber mixing mill,internal mixer(banbury),dispersion mixe(kneader) ,rubber calender,rubber extruder,plate vulcanizer machine,rotary curing machine,precure tread liner moulding press machine,rubber powder and reclaimed rubber equipment,rubber hoses production line,rubber strip production line,tire building machine,heating water deaerator,tire shaping& curing press,cord splitting machine,cycle tire equipment,raw material machinery,check & measuring equipment,etc.
We warmly welcome new and old customers home and abroad,friends from all walks of life to negotiate and cooperate with us.Let's co-create a better future!
Natural rubber is an elastomer—an elastic hydrocarbon polymer—that was originally derived from a milky colloidal suspension, or latex, 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. The entropy model of rubber was developed in 1934 by Werner Kuhn.
Varieties
The major commercial source of natural rubber latex is the Para rubber tree (Hevea brasiliensis), a member of the spurge family, Euphorbiaceae. This is largely because it responds to wounding by producing more latex.
Other plants containing latex include Gutta-Percha (Palaquium gutta),rubber fig (Ficus elastica), Panama rubber tree (Castilla elastica), spurges (Euphorbia spp.), lettuce, common dandelion (Taraxacum officinale), Russian dandelion (Taraxacum kok-saghyz), Scorzonera tau-saghyz, and Guayule (Parthenium 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 rubbers. To distinguish the tree-obtained version of natural rubber from the synthetic version, the term gum rubber is sometimes used.
Discovery of commercial potential
Charles Marie de La Condamine is credited with introducing samples of rubber to the Académie Royale des Sciences of France in 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 referred to as the first scientific paper on rubber.
The para rubber tree initially grew in South 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. When samples of rubber first arrived in England, it was observed by Joseph Priestley, in 1770, that a piece of the material was extremely good for rubbing out pencil marks on paper, hence the name "rubber".
South America remained the main source of what limited amount of latex rubber was consumed during much of the 19th century. However in 1876, Henry Wickham gathered thousands of seeds from Brazil, and these were germinated in Kew Gardens, UK. The seedlings were then sent to Ceylon (Sri Lanka), Indonesia, Singapore and British 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 labor. Liberia and Nigeria also started production of rubber.
In 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. The first commercial Hevea plantations in India were established at Thattekadu in Kerala in 1902.
CMG International Trading Dalian Co,Ltd
Contact Person: William Yang
MSN: williamy98@hotmail.com
Telephone: 86-0411-82766648
Fax: 86-0411-82766647
E-Mail: williamy98@yahoo.com.cn
Address: 22th floor,wan ke mansion,NO.67 Tong Xing street,zhong shan district,Dalian,Liaoning provice,China
