Studies On The Assessment And Determination Of Photo-Biodegradable Films

Two parts were included in this paper. In the first part, the correlation of some methods, four assessment indexes and the agricultural effects of photo-biodegradable films were studied. The second part was focused on the determination of starch-containing degradable plastics. The major results showed as following:1.For photo-biodegradable films containing more photosensitizer and starch farmland tests could be replaced by exposure to natural weathering test, two kinds of soil-burial tests and microorganism culturing test could be replaced each other when select suitable indexes.Appearance, viscosity-average molecular weight, carbonyl value (A1715 cm-1/ A2020 cm-1) and carbon-oxygen index are recommended to assess the photodegradability of photo-biodegradable films. Intensity of microorganism's growth, carbon-oxygen index, hydroxide group index are recommended to assess the biodegradability of photo-biodegradable films. When assess the biodegradability of photo-biodegradable films after photo degradation, intensity of microorganism, carbonyl value, carbon-oxygen index, hydroxide group index, weight are suggested to select.It's also showed in this research that the biodegradation of photo-biodegradable films could be manifested apparently only after the : photodegradation, and only biodegradation has little effect on the structure of the big molecular. So it is recommended that when assess the degradation of photo-biodegradable films, photodegradation is necessary to test at first, then biodegradation test is to conduct. It's also suggested that how to use photo-biodegradable films correctly and research new kind of degradable plastics.Photo-biodegradable films can increase and preserve temperature at farmland as common plastics. But it's different according to sunlight. The photo-biodegradable films in this research have effect on the early growth of cotton compared with the common film, while the effect is little on the reproductive growth.2.This paper suggest that the methods of visual examination, combustion watching, Iodine and acatic acidphenylamine test strips of chemical methods, IR spectroscopy and electron microscope of instrumental analysis methods should be used for the qualitative analysis of the starch-containing degradable plastics; Spectrophotometric method should be used to determinate the starch of it. These nine methods are useful for the development and application of this kind of plastics.