Polymers petrochemical-based

Another approach is to replace petrochemical-based polymers with polymers made from carbohydrates (14). Unfortunately, approaches of this type have yet to produce economically competitive polymers. 

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. 

Figure 1. Possible routes for biological and chemical degradation of starch-plastic composites. Note that direct biological degradation of petrochemical-based polymers does not occur. Rather, these polymers must first undergo chemical degradation to form as yet uncharacterized, lower molecular weight intermediates.

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. 

The rising cost of petrochemical-based polymers over the last two years. 

Automotive is one of the largest markets for thermoplastics, but to date few applications have been developed for biodegradable polymers. This situation is expected to change over the next five years as more auto manufacturers examine the possibilities offered by biodegradable polymers to replace petrochemical-based polymers. 

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—... 

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. 

The bio-based polymer and composites open new windows for becoming independent from petrochemical-based polymers and also free of environmental and health concerns. 

In general terms, polymers obtained from renewable resources can be significantly lower in greenhouse gas emissions and fossil energy use as compared with conventional petrochemical- based polymers. Over the long term, LCA demonstrates that PLA production processes can become both fossil-energy free and a source of carbon credits. ... 

For a comparison of PLA ecoprofiles with traditional petrochemical-based polymers the same methodology, software, and core databases were developed as used in the Association of Plastics Manufacturers of Europe (APME) analyses. The APME has over the last ten years published a series of ecoprofiles for traditional petrochemical-based polymers [12]. 

It needs to be recognized that the data for PEAl and PEA B/WP represent engineering estimates. In addition, there is good reason to expect improvements in the actual performance versus the estimates. Despite years of development work, the commercial manufacturing process for PEA is in its infancy. If the experience from petrochemical-based polymers offers any instruction, it is that process improvements implemented in the early years of a technology typically lead to substantial cost improvements. This is because the pursuit... 

The properties of PLA are significantly influenced by the stereochemistry of its monomers. When PLA has high stereochemical purity, it tends to form a highly crystalline structure. Copolymerization of different lactide isomers can yield a variety characteristics of PLA. The effect of isomerization in PLA can be detected by IR and NMR spectroscopic methods. Many studies have proven that PLA has a low solubility in a wide range of solvents/liquids, such as water, alcohol and paraffin. This indicates that PLA can be safely employed as a food packaging material without causing adverse health effects. In addition, PLA also possesses barrier properties that are just as effective as LDPE and PS. The green aspect of PLA means that it represents a viable environmentally friendly substitute for petrochemical-based polymers. 

The development of new biodegradable materials with good barrier properties is important since these materials can be used in many applications, such as toxic metal separation from wastes and especially in the packaging industry, which aims to replace the non-degradable and petrochemical-based polymers that are currently used for these purposes [21,78],... 

There is also a general interest in the sustainable production of chemicals and/or materials from renewable biomass feedstock. Indeed, they are regarded as promising materials that could replace petrochemical based polymers, reduce global dependence on fossil fuel sources and provide simplified end-of-life disposal [34]. The major chemical constituents derived from low-value biomass (i.e. lignocellulosic source) with potential to combine with polyolefins are cellulose, hemicelluloses, lignin and suberin. 

The increasing amounts of plastic products from petrochemical-based polymers in a landfill have led to serious environmental concerns over the past decade. In recent years, various biodegradable plasties have been developed as a sustainable alternative to replace commodity synthetic plastics. Polylactic add is typical biodegradable polyester produced from renewable resources and a versatile polymer that has been used for many applications in the biomedical industry [1] as well as the packaging industry [2,3]. PLA has been blended with other biodegradable and synthetic polymers for the development of improved properties, such as poly (e-caprolactone)[4], poly (vinyl butyral)[5], poly(3-hydroxy butyrate)[6], poly (ethylene oxide)[7], and poly(p-vinyl phenol) [8]. 

---