Plastics biodegradable, ideal

The high sensitivity and accuracy of XPS, coupled with low analysis depth and the detailed ehemical information it provides, make it an ideal analytical tool for studying surfaces important in biological contexts. XPS analysis has been used to detect the oxidation states of titanium in thin films as an indication of biocompatibility, with thinner films having a higher proportion of titanium dioxide. Modifications to PET polymer surfaces by marine bacteria were also detected by XPS, which may be the initial stages of plastic biodegradation. 

The ability of a degradable plastic to decay depends on the structure of its polymer chain. Biodegradable plastics are often manufactured from natural polymers, such as cornstarch and wheat gluten. Micro-organisms in the soil can break down these natural polymers. Ideally, a biodegradable plastic would break down completely into carbon dioxide, water, and biomass within six months, just like a natural material. 

A frequently cited merit of biodegradable plastics is their lack of persistance in an intact state "environmentally friendly" is a widely used vernacular phrase, but there has also been speculation in the popular press that degradable plastics will release potentially harmful additives into the environment when the plastics degrade or disintegrate. An ideal biodegradable plastic will leave no undegraded polymeric residues, and for these materials, the persistance of additives as well as the polymers must be considered. In this case, the issue is not whether or not the additive... 

The polymer polyhydroxybutyrate (PHB), a polyester of 3-hydroxy-butanoic acid, is completely biodegradable as it is an ideal food for microbes. By copolymerization with another hydroxyacid, such as 3-hydroxypentanoic acid, the polymer can be tailored to take it suitable either for molded articles such as shampoo bottles or thin films for plastic envelopes or carrier bags. PHB is tradenamed Biopol by ICI. Most of the polymer that the company makes is used for packaging, agricultural products, and items of personal hygiene. Wella, the German hair-care company, sells its Sanara brand of shampoo in bottles made of Biopol and has reported increased sales as a result. 

A solution to this problem would be to reduce unnecessary usage of plastics and to recycle used plastic materials. These conservational efforts could be further aided by replacing some pefrochemical-based plastics with biodegradable material possessing similar properties. One such potential candidate is PHA. This biodegradable polymer with thermoplastic properties is an ideal substitute for conventional plastics. 

WG is an ideal candidate for development of biodegradable materials because WG plastics can fully biodegrade without releasing toxic products (Domenek et al., 2004). 

In addition, the ideal plasticizer for PLA should be a low-volatility liquid, derived from green sources and biodegradable. The lactide monomer is obviously highly compatible but is too small a molecule, so it is easily lost from the system [11, 12]. Oligomeric lactic acid is also highly compatible, but the reduction in modulus is unacceptable. Awell-known green plasticizer is acetyl triethyl citrate. With HSP of (16.6, 3.5, 8.6), its distance from PLA is an unfortunately high 8. The other common citrates are no better the popular acetyl tributyl citrate has HSP of (16.7, 2.5, 7.4) and a distance of 8.4. It is no surprise, therefore, to find that a big problem with the citrates is their tendency to bleed out of the PLA. Similarly, triacetin (16.5,4.5,9.1) has a distance of 7.4. The common adipate plasticizers are also poorly compatible. 

The general and product specification targets for ideal biodegradable plastics films, as recognized in laboratories concerned with the development of materials for one-trip packaging applications, can be listed as follows. They should ... 

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