Manufacturing processes, natural/organic

Manufactured fibers produced from natural organic polymers are either regenerated or derivative. A regenerated fiber is one which is formed when a natural polymer or its chemical derivative is dissolved and extmded as a continuous filament, and the chemical nature of the natural polymer is either retained or regenerated after the fiber-formation process. A derivative fiber is one which is formed when a chemical derivative of the natural polymer is prepared, dissolved, and extmded as a continuous filament, and the chemical nature of the derivative is retained after the fiber-formation process. 

Petroleum asphalts, compared to native asphalts, are organic with only trace amounts of inorganic materials. They derive their characteristics from the nature of their cmde origins with some variation possible by choice of manufacturing process. Although there are a number of refineries or refinery units whose prime function is to produce asphalt, petroleum asphalt is primarily a product of integrated refineries (Fig. 1). Cmdes may be selected for these refineries for a variety of other product requirements and the asphalt (or residuum) produced may vary somewhat in characteristics from one refinery-cmde system to another and even by cut-point (Table 2) and asphalt content (Fig. 2) (5,6). The approximate asphalt yields (%) from various cmde oils are as follows ... 

Natural nuclear reactors, 17 589 25 397 Natural organic polymers, manufactured fibers produced from, 24 616 Natural photocatalytic processes, in the environment, 19 100-101 Natural plant growth regulators, 13 22-28 Natural polymer hollow fibers, 16 23... 

The presence of organic contaminants as small as 1 /tm or films as thin as 1 /rm on silicon wafers during the manufacturing process of integrated circuits can be readily identified (38). These contaminants can affect the performance of the device and must be identified. Figure 3-8 shows the identification of possible Teflon contaminants. Other techniques, such as IR, X-ray diffraction, Auger and electron microprobe, are insensitive in identifying the nature of the contaminant. 

Many of the natural organic colors in this category are extracts of a specific planf or insecf. These exfracfs are then processed into a usable form. Because of the different sources of these materials, the properties vary greatly for each colorant and also exhibit batch-to-batch variation. Because of the types of raw materials used and the difficulties in manufacture, these materials tend to be very costly. 

The chemical nature of the surface of carbon black is crucial to its applications-related behavior and in the first instance is a function of the manufacturing process. In addition to physically adsorbed organic substances, chemically combined surface oxygen is present on the surface, which is formed upon pyrolysis in the presence of sufficient oxygen and accounts for the acidity of gas blacks. Furnace blacks produced in oxygen-poor conditions with feedstocks with low sulfur contents have an excess of basic metal oxides on their surfaces and have neutral to alkaline properties. The content of physically and chemically bonded species is known as the volatile content, since it can be removed by heating to 950°C in the absence of air. 

The previously described manufacturing processes for flavour chemicals and flavour extracts primarily regard the physical and physico-chemical isolation and purification of naturally occurring flavour chemicals derived from plant and animal tissue. The huge area of organic chemical synthesis of nature-identical and synthetical flavour chemicals is not within the scope of this book. 

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