Bio- and Photo-degradation

On a more commercial front, the photooxidation of polymers continues to attract attention with a sustained special interest in natural cellulosic-based materials. Bio- and photo-degradable plastics are important for agricultural usage although interest in this area appears to be in decline. The same applies to polymer stabilisation where commercial applications dominate very much with much emphasis on the practical use of stabilisers. The stability of dyes and pigments continues to be of major concern. 

Torres, F.G., Arroyo, O.H., Grande, C., Esparza, E. Bio- and photo-degradation of natural fibre reinforced starch based biocomposite. Int. J. Polym. Mater. 55, 1115-1132 (2006)... 

Better known perhaps for its Spread-R shells and shell inserts designed to disperse shot patterns quickly, Polywad s GreenLite shell line use a wad-less technology with a light load (about 3/8 ounce) of steel shot. Components from the steel shot itself to the brown paper wad - except for the shell case (or hull ) which can, though, often be reloaded - are bio- and photo-degradable. 

Poly(ethylene terephthalate), PET, has become one of the major post-consumer plastic wastes. PET products do not present a direct threat to the environment, but they do pose a problem of considerable concern due to the huge amount of solid waste produced [1]. The disposal of this waste together with its low bio-degradability and photo-degradability, now represents a serious challenge for industrial countries worldwide. 

The degradation of aromatics, pesticides, herbicides, and other bio-recalcitrant compounds in industrial wastewaters can be efficiently achieved by means of the oxidative radicals generated in the Fenton and photo-assisted Fenton reaction [11], Among others, the photo-Fenton method has proved to be effective in the degradation of phenol and its halogenated derivatives [12-14], dioxins [15], nitroaniline [16],... 

Fig. 2 Water, and thus contaminants, enter alpine lakes in various ways mcluding melt water from glaciers (A), alpine streams (B), precipitation directly onto the surface (C and D), and from groundwater (E). Routes out of the lake include output streams (F), groundwater and volatilization (G). Transformative losses include photo-(H) and bio-(I) degradation. Storage in the lake can occur in the water column (J), sediment (K), or biota (L)...

Starch degrades by two mechanisms photo- and bio-degradation. Eor this reason, most blends with synthetic resins will be sensitized by addition of organometallics — transition metal compounds. The rate of degradation is sensitive to temperature. 

Ikada, E., 1997. Photodegradation behaviors of aliphatic polyesters. Photo- and bio-degradable polyesters. J. Photopolym. Sci. Technol. 10, 265—270. 

Kent believes that development of the photo-bio-degradable wad - it deteriorates when left exposed to the open air and sun - plus a quality steel load are superior for competition or field. 

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