Urea-formaldehyde plastics

Mouldings from melamine-formaldehyde powders are superior to the urea-formaldehyde plastics in a number of respects. 

Urea is used to make urea-formaldehyde plastics and resins and, increasingly, as a nitrogenous fertilizer (46.7% N). World production of urea was 23 million tonnes in 1984. 

Severe corrosion can be caused by organic acid fumes such as acetic or formic acids. These can be liberated by new wood, especially oak, and also by varnishes, glues, urea formaldehyde, plastics, fabrics and drying-oil paints, which can liberate fumes for a considerable time after application ... 

A typical cellulose-filled urea plastic has a tensile strength of 55,000 kPa, an Izod impact strength of 16 cm N/per centimeter of notch, and a coefficient of linear expansion of 3 X 10 3 cm/cm C. Urea-formaldehyde plastics have good electric insulating properties. Unlike phenolic plastics, urea plastics do not carbonize when an electric arc is placed on their surfaces. They also have a high dielectric strength. 

The plastic foam of 0.2mm dispersiry was homogenized with the expl components pre-ground in an edge runner. Thus, a mixt of 78.5% AN, 14.5 TNT, 5 urea-formaldehyde plastic foam, and 2% PETN was homogenized to have product of d 0.7 ]... 

In spite of Baekeland s success, it was another two decades before the Age of Polymers can really be said to have been born. The 1920s and 1930s saw the invention and/or commercialization of a number of new polymeric products ("plastics") that most consumers now consider to he essential chemicals in their lives. These products include the urea formaldehyde plastics (1923), polyvinyl chloride (PVC 1926), polystyrene (1929), nylon (1930), polymethylmethacrylate (acrylics 1931), polyethylene (1933), the melamine plastics (1933), polyvinylidene chloride (Saran 1933), polyvinyl acetate (PVA 1937), and tetrafluoroethylene (Teflon 1938). 

Urea. H2NCONH2, is excreted in the urine as the chief nitrogen-containing end product of protein metabolism. It is synthesized on a large scale for use as a fertilizer and as a raw material in the manufacture of urea-formaldehyde plastics and of drugs. 

Urea is used in the manufacture of urea-formaldehyde plastics, adhesives, polymers, synthetic fibers, dyes etc. 

Glassine A thin, transparent, and very flexible paper obtained by excessive beating of wood pulp. It may contain an admixture such as urea-formaldehyde plastic to improve strength. 

These inventions were in many fields from food products to cracked petroleum but his preference was polymer technology. He was awarded patents by the U.S. Patent Office on the first automobile enamel, urea formaldehyde plastics and fiberglass-reinforced polyester plastics. 

Ammonia is easily liquefied, and the liquid is used as a nitrogen fertilizer. Ammonium salts, such as the sulfate and nitrate, are also sold as fatilizers. Large quantities of ammonia are converted to urea, NH2CONH2, which is used as a fertilizer, as a livestock feed supplement, and in the manufacture of urea—formaldehyde plastics. Ammonia is also the starting compound for the preparation of most other nitrogen compounds. 

The only other major group of thermosets are the phenol formaldehyde and urea formaldehyde plastics. These are often used for closures in the cosmetic industry and are either coated to colour co-ordinate the component or vacuum metallised. 

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