Photodegradation biodegradation studies

Scott G, Gilead D (1995) Degradable polymers. Chapman Hall, London Copinet A, Bertrand C, Longieras AY et al (2003) Photodegradation and biodegradable study of a starch and poly(lactic acid) coextruded material. J Polym Environ 11 169-176 Thurston D, Lloyd S, Wallace J (1994) Considering consumer preferences for protection in material selection. Mater Des 15 203-209... 

Of the polymers studied the methylated polyamides B and C are both biodegradable and photodegradable. Their use in agriculture are being studied. 

Four papers have appeared on the photodegradation of PCBs on sediments [118-121]. Tang and Myers, for example, have carried out a study to model the behavior of PCBs on sediments confined in disposal facilities [ 118, 120]. In their glass aquariums the authors found PCB levels decreased by 40% over a 5-month span. Unfortunately, they were unable to pin point the source of the loss. Tang and Meyers believed the loss was due to a combination of volatilization, photo degradation and biodegradation. 

The mobility and fate studies have involved research on the leaching of dioxin from the soil (3), vaporization of the organic contaminants into and out of the soil (4), the biodegradation or chemical decomposition of the organics in the soil column (5), and the photodegradation of the organics in the soil (6,7). These studies usually have involved laboratory investigations or computer simulation of tests started many years ago. 

Unsaturated carbon-chain polymers e.g. the polydiene rubbers discussed above) are very susceptible to peroxidation and hence biodegradation. Some of these have been studied as photodegradable polymers in their own right. For example 1,2-poly (butadiene) is a plastic with properties similar to the polyolefins. In unstabilised form it photo-oxidises and thermooxidises rather too rapidly to be very useful commercially. 

Tsuji, H., Echizen, Y. and Nishimura, Y. (2006) Photodegradation of biodegradable polyesters A comprehensive study on poly(L-lactide) and poly(E-caprolactone). Polymer Degradation and Stability, 91, 1128-1137. 

Biodegradable trays from cassava starch, sugarcane fibers and sodium montmoriUonite have been developed by a baking process (7). A nanoclay dispersion, resulting in an exfoliated structure was obtained. The physical properties, the photodegradation and biodegradation of these trays have been studied. The formulations resulted in weU-shaped trays with densities in the range of 0.19-0.30 gcm. ... 

Studies of the biodegradation of " C-labelled Ecolyte polystyrene [24] have confirmed the presence of the radiolabel in the growing hyphae of bacterial species as well as in proteins, nucleic acid derivatives, and the CO2 developed during the culture. In experiments in Guillet s laboratories with a closed terrarium, it was demonstrated that up to 5% of the carbon in a photodegraded " C-labelled Ecolyte polystyrene in the soil was converted into CO2 or directly into the growing plants during a five-month period. 

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