Carbon-nitrogen-phosphorus polymers

In the following sections some examples are given of the ways in which these principles have been utilized. The first example is the use of these techniques for the low temperature preparation of oxide ceramics such as silica. This process can also be used to produce alumina, titanium oxide, or other metal oxides. The second example describes the conversion of organic polymers to carbon fiber, a process that was probably the inspiration for the later development of routes to a range of non-oxide ceramics. Following this are brief reviews of processes that lead to the formation of silicon carbide, silicon nitride, boron nitride, and aluminum nitride, plus an introduction to the synthesis of other ceramics such as phosphorus nitride, nitrogen-phosphorus-boron materials, and an example of a transition metal-containing ceramic material. 

Inorganic polymers have backbone chains that do not contain carbon, as organic polymers do, but atoms such as oxygen, nitrogen, phosphorus, boron, silicon, and metals or alternating combinations of them. The side groups attached... 

Polyhydroxyalkanoate is a polyester identified in 1925 by the microbiologist Maurice Lemoigne. It can be synthesised by various bacteria (Alcaligenes Eutrophus, cyanobacteria). Lower concentrations of carbon, nitrogen and phosphorus sources increase the yield and the quality of the polymers produced (Steinbiichel, 2002). There are numerous potential applications for PHA (cosmetics containers, disposable articles, medical implants, paper coatings). Moreover, PHA can be formulated in many grades, from elastic products to crystalline ones, it is a good candidate for blends and easy to process with traditional equipment (Whitehouse, 2000). 

Because of the processes carried out in the plant, the expected compounds in wastewater are formaldehyde, urea, and polymers of these compounds. The global effluent of this kind of factory is characterized by a high chemical oxygen demand (COD) (due mainly to formaldehyde), relatively high values of nitrogen (arising from urea and copolymers) and a low content of phosphorus and inorganic carbon. The main characteristics of the effluent of a resin factory are showed in Table 19.1. 

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