Materials petrochemically-based

The biomedical uses of polyphosphazenes mentioned earlier involve chemistry that could in principle be carried out on a classical petrochemical-based polymer. However, in their bioerosion reactions, polyphosphazenes display a uniqueness that sets them apart. This uniqueness stems from the presence of the inorganic backbone, which in the presence of appropriate side groups is capable of undergoing facile hydrolysis to phosphate and ammonia. Phosphate can be metabolized, and ammonia is excreted. If the side groups released in this process are also metabolizable or excretable, the polymer can be eroded under hydrolytic conditions without the danger of a toxic response. Thus, poljnners of this tjT are candidates for use as erodible biostructural materials or sutures, or as matrices for the controlled delivery of drugs. Four examples will be given to illustrate the opportunities that exist. 

The shift to oleochemicals has been supported by increasing environmental concerns and a preference by some consumers, especially in Europe, for materials based on natural or renewable resources. Although linear alkylbenzenesulfonates (LASs) are petrochemically based, alcohol ethoxylates, alcohol ethoxysulfates, and primary alcohol sulfates are derived from long-chain alcohols that can be either petrochemically or oleochemically sourced. There has been debate over the relative advantages of natural (oleochemical) vs synthetic (petrochemical) based surfactants. However, detailed analyses have shown there is litde objective benefit for one over the other. 

There can be little doubt that oxygen-containing hydrocarbons (oxygenates) will play an increasingly prominent role as components of motor fuels and, potentially, as raw materials for other petrochemical-based processes. The last decade has seen increasing use of oxygenates, including alcohol blends and methyl tertiary butyl ether (MTBE), as octane... 

Zeolitic materials have been widely used in the last decades in the chemical and petrochemical industries. This increasing interest on these materials is based in their unique properties a uniform intra-crystalline microporosity that provides aceess to a large and well-defined surface, the molecular sieve effect, and the electrostatic field centered at zeolite cations. Furthermore, some properties of zeolites can be tailored by changing the nature of the compensating cation located in the inner part of the cavities by means of their ion-exchange capability. In this way, the pore accessibility of some zeolites used in gas separation processes, as well as the adsorbent-adsorbate interactions, can be tailored by the introduction of cations with different size and chemical nature. Similarly, different cations can be used to introduce new chemical properties (acid-base, redox, etc.), which are needed for a given application in catalytic processes. 

The emergence of petrochemical-based polymer technologies and products underlay the most significant upheaval in the twentieth-century chemical industry. The 1920s witnessed a growing interest in polymer-based synthetic materials such as Bakelite, celluloid, and cellulose acetate. In the 1930s concentrated efforts—particularly by Du Pont, Dow, and Union Carbide—... 

In order to achieve that objective a variety of tools - both voluntary and mandatory - can be used such as economic instruments (e.g., funding, fees), substance bans, voluntary agreements, environmental labelling and product design guidelines. The application of principles of hfe-cycle analysis for additives clearly indicates that raw materials, energy and pollution from renewable resources are preferred when compared to petrochemically based processes and products. 

The synthesis of bacterial storage compounds is reviewed in Chapter 10, focusing on two systems, namely polyhydroxyalkanoic acids and cyanophycin. Bacterial storage compounds are very interesting biopolymers having attractive material properties, sometimes similar to those of the petrochemical-based polymers. 

In recent years, interest in plastics made from renewable materials (biological sources) has increased greatly. The drive towards increasing sustainability has enabled these plastics to become more competitive with petrochemical-based plastics. Many of these materials (though not all) are also biodegradable, which is also seen as a desirable attribute. Biodegradability will be discussed further in Chapter 16. 

For several reasons, a growing number of industries feel very strongly about sustainable product development. It is unavoidable that industries will be confronted with problems regarding die supply of petrochemical-based materials. Another aspect is the growing criticism from society and political circles of the effects of using such raw materials. The number of problems involved with the treatment of waste originating from by-products and main products at the end of their service life is increasing. Consequently, waste treatment will tend to become more expensive. 

Abstract Polyhydroxyalkanoate (PHA) initially received serious attention as a possible substitute for petrochemical-based plastics because of the anticipated shortage in the supply of petroleum. Since then, PHA has remained as an interesting material to both the academia and indusby. Now, we know more about this microbial storage polyester and have developed efficient fermentation systems for the large-scale production of PHA. Besides sugars, plant oils will become one of the important feedstock for the industrial-scale production of PHA. In addition, PHA will find new apphcations in various areas. This chapter summarizes the future prospects and the importance of developing a sustainable production system for PHA. 

All petrochemical-based substances have higher gross energy requirements (GER, indicates the total primary energy consumption of the manufacturing process of a chemical product from its raw material) than those... 

It was prophesied in the 1960s that oil-based paints would disappear from the market in about 20 years in favour of petrochemical-based products. This has not happened, and the main protective paints are still based on fatty oils. In fact, following the oil crisis, the trend has been back to raw materials from renewable resources. None of the new technologies such as the use of powder coatings, water-borne paints, or radiation-curing paints, which would not have been based on oils, have proved as versatile as expected. 

Due to the rapidly increased production cost of fossil (petroleum)-based chemicals, fermentatively produced fumaric acid from renewable resources could replace current petrochemically based maleic acid as unsaturated dibasic acid mainly in the polyester resin industry but also in medicine and food industries in the nearby future. However, this can be achieved only if the bio-based production process for fumaric acid would be economically competitive with the current fossil-based process. This change requires the improvement of the large, past-operating fermentation processes for acid production in many aspects, such as production of free acid at a low pH, product yield and productivity, cheap and renewable raw material, and problems related to cell morphology and mass transfer. 

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