Petroleum sources, synthetic polymer materials

Polymers are an indispensable commodity within modern society that is found in all sectors of a consumer economy, such as materials, pharmaceuticals, and energy. Typically derived from nonrenewable petroleum sources, synthetic polymers account for 7% of the gas oil consumed [1]. As of 2013, total US demand for crude oil was approximately 1 bUhon metric tons per year [2], and as humankind enters the twenty-first century, the search for renewable energy and materials is at an all-time high. To solve this problem, efforts have been focused on utilizing available renewable feedstocks. 

The first plastic made was cellulose nitrate, which is a derivative of cellulose, obtained from wood pulp. The first truly synthetic polymer material was phenolic resin, which was synthesized from phenol and formaldehyde derived from coal. Today, the source of organic chemicals for the production of polymers has shifted from these traditional sources to petroleum and natural gas. Petroleum as a raw material for organic chemicals (petrochemicals) is relatively cheap, readily available in large tonnages, and more easily processed than the other main source of organic chemicals — coal. 

On the other hand, completely synthetic polymers can be tailor-made, as it were, for the intended application. But their syntheses presuppose that suitable raw materials and sufficient energy are available. Petroleum is at present the main raw material source for synthetic polymers in addition, small quantities of intermediate products are also obtained from natural gas, wood, coal, and certain plants. Fossil fuels such as petroleum, natural gas, and coal, however, are the main sources of energy at present (Table 24-1), and so, these materials are simultaneously energy and raw material sources. This situation will not change significantly in the coming decades, since utilization of what are known as the infinite energy sources, that is, the sun, nuclear... 

For a 4% annual petroleum (the main energy source) increase per year k = 0.04), reserves will be fully exhausted in about 22 years, and all reserves and resources in about 64 years. Consequently there is an energy-saving compulsion to produce only those materials that require small amounts of energy. Synthetic polymers are to be preferred for this reason over glass and metals (Table 24-3), especially with respect to volume instead of weight. Of course, material is purchased with respect to weight, but used with respect to volume. 

Most of the fibrous waste is composed of natural and synthetic polymeric materials such as cotton, polyester, nylon, and polypropylene. The primary source of raw material for synthetic polymers is petroleum. Even for renewable natural polymers such as cotton, the production requires energy and chemicals that are based on non-renewable resources. Although the global petroleum reserve may last at least another several hundred years at the rate of current consumption, petroleum and other natural resources are non-renewable in practical terms. It is our responsibility to conserve these resources for the benefit of future generations. 

The manufacture of synthetic polymers consumes large quantities of petroleum for raw material, and synthetic and natural polymers make up a large fraction of solid waste. For these reasons, it is desirable to Ixrth make polymers from renewable biological sources and to synthesize and use polymers that will biodegrade after disposal. Nature has provided a large variety of polymer factories, producing useful... 

The ultimate starting materials for synthetic polymers are few in number. Petroleum, natural gas, coal tar, and cellulose are the main sources. In recent years, ethylene and propylene from natural gas and petroleum refining have been used as a starting point for a variety of monomers as well as serving as key monomers. The process of building up polymers from simple repeating units (monomers) can proceed with many variations. We can classify some of these as follows ... 

The xylenes are very high-lonnage industrial chemicals and are raw materials or intermediate materials for numerous synthetic fibers, resins, and plastics. See also Xylene Polymers. A large amount of p-xylene goes into polyester fiber production, while substantial quantities of d-xylene are consumed by the manufacture of phthalic anhydride. The prime source of xylenes are petroleum refinery reformate streams in conjunction with benzene and toluene extraction. The xylenes occur mixed in these streams. 

Commercially available activated carbons are prepared from carbon-containing source materials such as coal (anthracite or brown coal), lignite, wood, nut shell, petroleum and sometimes synthetic high polymers... 

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