Degradable Films' Degradation Characters And Their Effects On Soil Environment

The components and degradabilities of one kind of ordinary film and three kinds of degradable films were analysized by thermal analysis and infrared spectroscopy.Biodegradable film's degradability was tested by micro-organism culture.Degradable films' effects on com growth and soil environment were studied by field experiment and pot experiment.The results of thermal analysis showed that the DTA curves of four kinds of films had much similarity and seldom difference,which meant that degradable films had more same components as ordinary film,but their added components were very different.Films' pyrolysis reaction orders in maximum melting endothermic peak were about 0.93.The order of films pyrolysis's activation energies and anaphoric factors was:ordinary film>photodegradable film>bio-photodegradable film>biodegradable film.After films being mulched,the DTA curves of degradated films in test were as same as those of original films on the whole.The degradated films' temperature in maximum melting endothermic peak were higher than original films'.The degradated films' pyrolysis reaction orders in maximum melting endothermic peak were smaller than original films'.Ordinary film's pyrolysis's activation energy was decreased a little,photodegradable film's pyrolysis's activation energy was decreased more,by contrastjbiodegradable film and bio-photodegradable film's pyrolysis's activation energies were increased a little.Calculation from thermogravimetric curves showed that the content of starch in biodegradable film was about 21.05% and the content of calcium carbonate in bio-photodegradable film was about 10.91%.The thermogravimetric curves and differential thermogravimetric curves of degradated films in test was as same as those of the original films.The content of starch in biodegradable film and the content of calcium carbonate in bio-photodegradable film were all decreased.The results were also showed that differential thermal analysis and thermogravimetric were a simple and efficient methold to analysize films' components,study their pyrolysis characters and assess their degradabilities.Film's degradability can be judged by film's pyrolysis's activation energy.Biodegradable film and bio-photodegradable film can be differentiated by DTA curve and DTG curve's character peaks.Analysis of infrared spectroscopy showed that different kinds of film had their own infrared spectrum,ordinary film and degradable film can be differentiated by infrared spectrum,so did different degradable films.The infrared spectrum of mulched film for a certain period can show some changes of film's components and characters,which can be used to judged the state of film's degradation.Carbonyl index can be used as an quota to judge the state of film's degradation.The order of three kinds of degradable film's carbonyl indexes is:biodegradable film>bio-photodegradablefilm>photodegradable.The results of micro-organism culture showed that the degradable rate of the biodegradable film added with spore suspension was higher than that of the biodegradable film without spore suspension.The degradable rate of the biodegradable film added with soil suspension was higher than that of the biodegradable film without soil suspension. Compared different culture mediumSjthe order of degradable rates of the biodegradable films was:bacteria medium>actinomyces medium>fungi medium.The degradable rate of the biodegradable film with field soil suspension was the highest one.The degradable rate of biodegradable film was higher than that of ordinary film.The results of test under liquid culture showed that mixed bacterium were helpful to biodegradable film's degradation;the degradable rate of biodegradable film under liquid culture was higher than that of solid culture.The results of planting corn by mulching film showed that film mulching had obvious effect on soil water conservation at the middle stage of corn growth,but at the earlier and later stages this effect was not obvious.Film mulching had no obvious effect on raising soil temperature at the...