Fossil fuel-derived polymers

The development and use of materials from renewable sources is not a new concept. Besides providing food, feed, clothes, shelter, and energy, biomass has been employed since ancient times to extract valuable products such as medicinal drugs, flavors, and fragrances. With the development of civilization of human society, in the nineteenth century various biomass resources were employed for the large-scale industrial production of chemicals and durable materials, such as cellulose esters (nitrate and acetate), oxidized linseed oil (linoleum), vulcanized rubber, adhesives from starches, and so on. However, the widespread use of such renewable materials diminished in the twentieth century since the development of fossil fuel derivatives, leading to the polymer renaissance. Today commodity polymers such as polyolefins are ubiquitous in our societies because they represent the optimal choice based on several factors, including monomer cost and... 

Most of the plastics and synthetic polymers that are used worldwide are produced from petrochemicals. Replacing petroleum-based feedstocks with materials derived from renewable resources is an attractive prospect for manufacturers of polymers and plastics, since the production of such polymers does not depend on the limited supply of fossil fuels [16]. Furthermore, synthetic materials are very persistent in the environment long after their intended use, and as a result their total volume in landfills is giving rise to serious waste management problems. In 1992,20% of the volume and 8% of the weight of landfills in the US were plastic materials, while the annual disposal of plastics both in the US and EC has risen to over 10 million tons [17]. Because of the biodegradability of PHAs, they would be mostly composted and as such would be very valuable in reducing the amount of plastic waste. 

In contrast to the polymeric products derived from fossil fuels, the production of synthetic polymers from biomass—the rayons and cellulose acetates—is quite small despite the fact that cellulose is one of the world s most abundant raw materials. The rayons are any of a variety of regenerated celluloses manufactured via intermediates such as alkali salts and cellulose xanthates. The process... 

Recycling polymers The starting materials for the synthesis of most polymers are derived from fossil fuels. As the supply of fossil fuels is depleted, recycling plastics will become more important. Thermosetting polymers are more difficult to recycle than thermoplastic polymers because only thermoplastic materials can be melted and remolded repeatedly. 

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. 

Solid-state MAS NMR spectroscopy has had much success in examining amorphous insoluble polymers [59]. In recent years, however, there has been some debate on the reliability of quantitative data derived from CP experiments [60] and work on fossil fuels in particular has highlighted the problem [61,62]. Undoubtedly, the issues arise in the analysis of polymers as well [63-66]. While CP results in signal-to-noise enhancement and hence reduced accumulation times, carbon atoms present with no proximal protons tend to have their peak intensities reduced relative to other signals. Quaternary aromatic carbons are likely to suffer badly in this respect. The modulation of the dipolar interactions by the motion of some moieties can also introduce quantitative errors [67]. The rotation of the methyl group about its 3-fold axis of symmetry is a good example of this. Single pulse excitation (SPE) [60] however overcomes the problems that are associated with CP,... 

Starting materials are often referred to as feedstocks. Most of the starting materials (monomers) employed in the synthesis of synthetic polymers like polystyrene, polyethylene, and nylons are derived indirecdy from fossil fuels. The term fossil fuels refer to materials formed from the decomposition of once-living matter. 

A bio-based polymer on the other hand is a man-made polymer where the starting materials or raw materials (bnt not the polymer itself) are derived from living organisms (generally plants). These renewable feedstocks are used to make polymers varieties that are identical in chemistry to conventional fossil fuel-based plastics. 

In this chapter, alternatives to traditional polymers derived from fossil fuels are commented. Materials derived from plants and microorganisms are presented, as well as biodegradable materials obtained from fossil fuels. 

Other ROP reaction that will be discussed in this section was done on cyclic ester monomers to give polyesters (reaction 7.3). Currently organic chemicals are predominantly derived from petrochemicals. Polyethylene and polypropylene production are hugely increased during last decade. These polymers in addition to polyethers, polycarbonates, and polyesters are all derived from oil. But if we are going to run out of fossil fuels, we must find alternative chemicals which could be produced from renewable... 

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