Hevea brasiliensis latex, natural products from

Allergy to natural rubber latex, first reported in 1989 in the United States, is a common cause of occupational allergy for health care workers. Natural rubber is a processed plant product from the commercial rubber tree, Hevea brasiliensis. Latex allergens are proteins found in both raw latex and the extracts used in finished rubber products. Latex gloves are the largest single source of exposure to the protein allergens. ... 

The Production of Natural Rubber from Hevea brasiliensis Latex Colloidal Properties, Preservation, Purification and Processing... 

In 1994, the worldwide consumption of rubber was approximately 14.5 million tons a year, of which about 40% consisted of natural rubber. Natural rubber is produced as latex by tropical rubber trees (Hevea brasiliensis). It is processed locally and therefore the quality of natural rubber fluctuates remarkably [ 140]. Due to increasing demand for rubbers, combined with a decreasing production capacity in Asia and a vast increase in labor costs, the price of natural rubber is still rising sharply. In 1990-1994, the average price of natural rubber was about 0.38 /lb, while in 1996 it was already over 0.80 /lb. The remaining 60% of the articles were manufactured from synthetic petroleum-based rubbers such as isoprene rubber, styrene-butadiene rubber, chloroprene rubber and polyurethanes. The quality of synthetic rubbers is constant, and their price varies between 2 and 5 US per kilogram [137-140]. 

Renewable raw materials are made or derived from short-term renewable sources (one to a few years or a few tens of years) such as plants, trees, wood wastes and other agricultural products. Not all these materials are necessarily biodegradable. Natural rubber, for example, comes from the latex of a tree (Hevea brasiliensis) and is not biodegradable. Renewable materials are often considered as opposites to fossil sources such as petroleum that are not renewable on a human timescale. On the other hand, some synthesized plastics such as certain polyesters are biodegradable. 

Rubber is a natural product that exists as a colloidal dispersion named latex in the sap of certain plants from various families such as Moraceae, Compositae or Euphorbiaceae. From this last family, Hevea brasiliensis is the most common plant that produces natural rubber for practical use. The latex has rather large colloidal particles (in aqueous medium) with diameters up to 5 m (although the average is 0.5 jim). 

The modem elastomer industry was founded on the naturally occurring product isolated from the latex of the tree Hevea brasiliensis. It was first used by indigenous South Americans and was called caoutchouc, but, later, simply rubber, when it was discovered by Priestley that the material robbed out pencil marks. 

Natural rubber (NR) is elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by some plants (Hevea brasiliensis, a member of the spurge family, Euphorbiaceae). The plants are tapped by making an incision in the bark of the tree and collecting the sticky, milk-coloured latex sap, which is refined into usable rubber. The purified form of NR is the chemical polyisoprene, which can also be produced synthetically. NR is used in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof. 

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