Petrochemical-derived polymers

Starch-plastic composites contain a mixture of two very different types of materials (/) hydrophobic, petrochemical-derived polymers (PE, EAA) known to be highly resistant to degradation by living organisms, and (i7) a hydrophilic, natural polymer (starch) that is easily broken down by a wide array of organisms. In the process developed by Otey (3), these fundamentally incompatible materials are forced into an intimate mixture during production of the plastic film. Since... 

Abstract The development and production of biodegradable starch-based materials has attracted more and more attention in recent years due to the depletion in the world s oil resources and the growing interest in easing the environmental burden from petrochemically derived polymers. Furthermore, the unique microstructures of different starches can be used as an outstanding model system to illustrate the conceptual approach to understanding the relationship between the structures and properties in polymers. 

The reliance on petrochemicals for nonwovens is destined to change with increasing material consumption with movement towards polymers sourced from regenerative processes (Wiertz, 2014). There is already evidence of this shift, as the production of nonwoven materials from renewable resources is increasing, along with the number of biopolymers available. Where petrochemical-derived polymers remain economical or essential, the production of nonwoven products can be made more sustainable by including recycled polymers and fibres. 

Grafting reactions alter the physical and mechanical properties of the polymer used as a substrate. Grafting differs from normal chemical modification (e.g., functionalization of polymers) in the possibility of tailoring material properties to a specific end use. For example, cellulose derivatization improves various properties of the original cellulose, but these derivatives cannot compete with many of the petrochemically derived synthetic polymers. Thus, in order to provide a better market position for cellulose derivatives, there is little doubt that further chemical modification is required. Accordingly, grafting of vinyl monomers onto cellulose or cellulose derivatives may improve the intrinsic properties of these polymers. 

As one of the newest petrochemicals to make the big time, alpha olefins have found two niches. One is in the petrochemicals industry as precursors for detergents, copolymers, and specialty chemicals. The other niche is in this book, appropriately sandwiched in between the usual list of petrochemical derivatives and the polymers. The alpha olefins are indeed derivatives, but the process for creating them is more like polymerization than any other derivative process. 

Sulfur is present in the petrochemicals derived from once-living matter as it is present in certain amino acids. Because of its removal from industrial waste, sulfur has been stockpiled and is available at a low price in large amounts. While the stable form of sulfur at room temperature is cyclooctasulfur (Sg), linear polysulfur is formed on heating. Unfortunately, the thermodynamically stable form of sulfur is the cyclooctasulfur monomer and the polymer undergoes depolymerization after sometime. 

From the results presented in this chapter we can conclude that it is feasible to prepare sugar-based polymers analogous to the more qualified technological polymers - polyamides, polyesters, polyurethanes - with an enhanced hydrophilicity and degradability. However, in most cases, the high costs associated with the preparation of the monomers restrict the application of these polymers to biomedical applications and other specialized fields. More readily available monomers and simpler polymerization processes have to be found if sugar-derived polymers should compete with petrochemical-based polymers that are used in domestic applications. 

Acyltransferases are, for instance, able to synthesize biological polyesters with properties comparable or sometimes even exceeding polymers based on petrochemical-derived monomers. Acyltransferases are also frequently used to modify macromolecules in food and non-food applications. 

PHAs can consist of a diverse set of repeating unit structures and have been studied intensely because the physical properties of these biopolyesters can be similar to petrochemical-derived plastics such as polypropylene (see Table 1). These biologically produced polyesters have already found application as bulk commodity plastics, fishing lines, and for medical use. PHAs have also attracted much attention as biodegradable polymers that can be produced from biorenewable resources. Many excellent reviews on the in vivo or in vitro synthesis of PHAs and their properties and applications exist, underlining the importance of this class of polymers [2, 6, 7, 12, 26-32]. 

By contrast, when the product from crude oil is limited to only one or two specific hydrocarbons of fairly high purity, the fraction is called a petrochemical. Examples of petrochemicals are ethylene, propylene, benzene, toluene, and styrene. Refined products are defined by the fraction s boiling point and may be composed of various hydrocarbons. Multiple compounds compose refined-product fractions. In contrast, petrochemicals are single-compound fractions, which are required for feedstocks for other petrochemicals and polymers. More processing and separation (distillation, extraction, etc.) operations are used to extract petrochemical products from processing streams. Thus, more identifiable petrochemical products are processed than refined products. Many specific hydrocarbon compounds can be derived from crude oil. However, these hydrocarbons lose their individual identity when they are grouped together as a refined product. 

This increase in costs had a powerful effect on the markets of major intermediates in the developing countries. In the 1960s it was felt that the low cost of petrochemical derivatives, chiefly fertilizers and polymers, would, by the end of the century, become a decisive factor in the industrial growth of these countries. The prediedons made at the time are increasingly illusory. This can be attributed primarily to the weight of the raw material rice in the final product cost it accounts today for 85 per cent of the operating costs of a steam cracker, whereas in 1973 it only represented 48 per cent Moreover, for the same period, investments were multiplied by a factor of 4 in current value and by 1.6 in constant value. For these countries, this meant that petrochemical derivatives lost part of their character of cheap products, susceptible to widespread drculadon. 

Lastly we examine attempts to design structures for particular functions, namely, films that act as barriers and capsules that contain bioactive substances. In the future, we will need to create novelty in the long-term stability of products and delivery of specific molecules for a health benefit. These technologies are attracting attention not only from the food industry but also for nonfood use. Sustainable and environmentally friendly attributes of biomaterials are increasingly discussed, compared to petrochemically derived, synthetic polymers and plastics. For once, food materials scientists can teach other industries the rules of the game. ... 

Joanna D Underwood takes us into the world of commercial products in Section 7.2.2. It is too easy to see the chemical industry as quite distant from the local toy store or furniture maker. However, in a world where commodities are increasingly made from petrochemicals and polymers, which are derived from fossil fuels, the resulting products are often a puree of scores of chemicals, many added to control and tame the reactivity and decomposition of the fuel. Underwood notes how frequently many of these substances are persistent, bioaccumulative, and toxic, a combination of factors that when present in domestic products sets ripe conditions for human and ecological harm. She concludes that many of these substances have no place in a sustainable chemical industry. 

Since the plastics are produced from petrochemicals derived from hydrocarbons, the motivation to reuse, recycle, or reprocess for energy recovery is primarily driven by an interest in conservation of petroleum resources. Economic factors are also important, but the potential saving of landfill space is more a perception rather than a reality [9]. Most of the categories of vinylic polymers discussed in this chapter are melt-formable, that is, they are thermoplastic materials, rather than nonmelting or thermosetting as are several of the condensation polymers discussed in Chapters 20 and 21. Thus,... 

But they can compete only with petrochemically derived synthetic polymers for special application where biodegradability is the primary criterion. 

Butanediol (1,4 BDO) is an intermediate used to produce several important petrochemical and polymer derivatives. One of the most visible and widely used polymers is spandex fiber (polyurethane fiber) however, many other high performance polymers and solvents are made from 1,4 BDO. A complete description of supply, demand, and uses for its derivatives is included in Chapter 6. The manufacture of 1,4 BDO by each of several alternative commercial routes are major users of hydrogen for hydrogenation. 

When polymers or commodity production in the chemical industry is considered, a tacit consensus is that plants cannot compete with petrochemically derived... 

Figure 2.3 Number of newly developed polymers between 1900 and 2020 (prediction). Petrochemically derived building blocks had been mainly developed in the 1940s and 1950s of the 20th century. New biopolymers...

For 20 years prior to those mid-50 s, there had been an established, and growing, industrial fermentation industry, based mainly on the use of blackstrap molasses as a substrate. Then, beginning the hydrocarbon age, there came the petrochemicals, derived from the ever-so-cheap barrel of crude. The byproducts of the petroleum industry had unlimited promise for chemical productions. Olefins and the polymers were starting their boom. Everything grew bigger, very rapidly. Everyone took it that the cheap barrel of crude would, like diamonds, be forever. As for the fermentation industry - it was a case of "off with old, and on with the new". Hence, the statements like that of Hastings. 

---