Environmentally acceptable polymers

Hence, we have reached a critical point where there is a very real need to reassess what we have accomplished, are developing and categorically specifying as biodegradable and, therefore, environmentally acceptable polymers. 

Modification of natural polymers such as starch, cellulose, proteins, etc. is a way of capitalizing on the well-accepted biodegradability of the base material with the intention of developing biodegradable or environmentally acceptable polymers that function in variety of commercial applications. It is essential, of course, to demonstrate that the modification does not to interfere with the biodegradation process and the product meets the guide listed earlier for environmental acceptability, namely ... 

J. E. Glass, ed.. Hydrophilic Polymers Performance with Environmental Acceptance, Advances in Chemistry Series 248, American Society, Washington, D.C., 1995. 

There are signs that the use of environmentally degradable polymers and plastics is expanding. As the market begias to become aware of the availabihty of these new materials, it is expected that they will move iato niche opportunities. When this occurs, production will iacrease, and costs, the biggest barrier to acceptance, should begia to come down. Some of the polymers ia production at some scale larger than laboratory are shown ia Table 5. 

International agreement is close as of 1996 on what an acceptable environmentally degradable polymer should do ia the environment succiacdy put, it must not harm the environment. There has been much progress ia the early 1990s on this issue standard protocols are available to determine degradation ia the environment of disposal, and definitions are understood and accepted ia a broad sense, if not ia detail. Fate and effects issues for these new polymers are being addressed, and these will be resolved and appropriate tests developed. 

JD Andrade, V Hlady, SI Jeon. Poly(ethylene oxide) and protein resistance Principles, problems, and possibilities. In JE Glass, ed. Hydrophilic Polymers Performance with Environmental Acceptability. Adv Chem Ser 248. Washington DC American Chemical Society, 1996, pp 51-59. 

The polymerization of phenols or aromatic amines is applied in resin manufacture and the removal of phenols from waste water. Polymers produced by HRP-catalyzed coupling of phenols in non-aqueous media are potential substitutes for phenol-formaldehyde resins [123,124], and the polymerized aromatic amines find applications as conductive polymers [112]. Phenols and their resins are pollutants in aqueous effluents derived from coal conversion, paper-making, production of semiconductor chips, and the manufacture of resins and plastics. Their transformation by peroxidase and hydrogen peroxide constitutes a convenient, mild and environmentally acceptable detoxification process [125-127]. 

Note 2 Usually, degradation results in the loss of, or deterioration in useful properties of the material. However, in the case of biodegradation (degradation by biological activity), polymers may change into environmentally acceptable substances with desirable properties (see Definition 3.1... 

Over 30% of the chlorine produced on a global basis goes to make PVC. Chlorine makes PVC inherently flame-retardant. PVC is over 50% chlonne and. as a result, one of the most energy-efficient polymers. Chlorine makes PVC far more environmentally acceptable than other materials that are totally dependent on petrochemical feedstocks. In addition, recycling... 

In recent years there has been a resurgence of interest in polysilicate-based formulations, incorporating materials such as pyrophos-phate/TTA/nialeic acid terpolymer and other polymers. These are also designed for softer waters and have been billed as environmentally acceptable products. 

Another area of environmental concern is the products themselves. Petroleum refining in the last 10 years has been driven by requirements for the composition of gasoline and diesel fuel that are continuously changed by environmental demands. Such considerations will have even stronger impact in the future. There are similar problems in the chemical process industries. The search for an environmentally acceptable substitute for Freon is a prominent present example. Another problem is polyvinyl chloride (PVC), which causes difficulties in incinerators. The question is, should we continue to produce PVC or should we find a substitute that is easier to dispose of Can we modify polymers in such a way that they cause fewer problems of pollution than they cause now These are major challenges for the profession, in both academia and industry. 

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