Nitrogen-containing plastics

M. Watanabe, C. Nakata, W. Wu, K. Kawamoto, and Y. Noma, Characterization of semi-volatile organic compounds emitted during heating of nitrogen-containing plastics at low temperature, Chemosphere, 68(ll) 2063-2072, August 2007. 

FIGURE 5.1 Tests for group II, nitrogen-containing plastics. 

The composition of combustion gases from nitrogen-containing plastics (such as polyacrylonitrile, polyamides, polyurethanes, urea and melamine resins) is by no means clear. In most cases, carbon monoxide is accompanied by hydrogen cyanide, ammonia, and nitrous gases in the gas mixture. Their concentrations are greatly influenced by the burning conditions. 

In a rotary kiln, the burner can produce both thermal and fuel NO, if the fuel contains nitrogen. Many soHd waste streams also contain nitrogen, typically as much as 20 wt %, which contributes to the fuel NO pathway. Key sources of soHd waste fuel nitrogen include plastics, nylons, dyes, and other process wastes. Nylon, for example, is 33 wt % nitrogen. 

Plastics produced by the reaction of formaldehyde and melamine or cyanuramide were introduced commercially in 1939. Today urea is also em ployed as a nitrogen-containing reactant. These are often discussed under the... 

Among the most frequently used nitrogen containing polymers in electrical, electronic, and automotive applications are PA and ABS. Pyrolysis proved to be a suitable method for recycling plastic waste. 

With these many requirements, it is obvious that each group of polymers has its own plasticizers, although some types of plasticizers have been developed which are suitable for several plastics. They belong to the groups of esters, ketones, ethers, acetals, epoxides, and nitrogen containing compounds like the sulfonamides. 

Ammonia is used for the manufacture of fertilizers or for the manufacture of other nitrogen-containing compounds used for fertilizer or, to a lesser extent, explosives, plastics, and fibers. Explosives made from ammonia are ammonium nitrate and (via nitric acid) the nitroglycerin used in dynamite. Plastics include (via urea) urea-formaldehyde and melamine-formaldehyde resins. Some ammonia ends up in fibers, since it is used to make hexameth-ylenediamine (HMDA), adipic acid, or caprolactam, all nylon precursors. 

Ammonia X X X X Fertilizer and animal feed production manufacture of fibre, plastics, explosives, paper and rubber coolant metal processing starting production for many nitrogen-containing compounds cleaning agents food additive diuretic 311/2,3210,341, 351,3523,3529, 355, 38... 

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. 

Octacarbonyldicobalt (3.42 g., 10 mmoles) is weighed out in a nitrogen-filled plastic glove bag and transferred to a 250-ml. singlenecked flask containing 50 g. 1% sodium amalgam in 100 ml. of anhydrous tetrahydrofuran. The mixture is stirred for 3 hours under... 

Watanabe and Sato (1972) observed that this product adds a slightly caramel-like character to the flavor of cooked beef, but Peterson et al. (1975), on the contrary, considered that it confered to canned beef stew an unpleasant antiseptic-like aroma, reminiscent of plastic. Buttery (1999) compared several 2-acyl nitrogen-containing heterocycles with a cracker, popcorn-like aroma character 2-acetylpyrrole is the less potent with a threshold of 170ppm in water (the 3,4-dihydro-2//-pyrrolyl derivative has a threshold of 0.1 ppb and the pyridyl derivative, N.22, of 19ppb). 

---