Preparation And Study On Biodegradable Plastics Film Of Methyl Corn Starch Blends With PVA

Corn starch as material, methyl starch with different degree of substitution (DS) was prepared by means of dimethyl sulphur ester, then blends with biodegradable polymer Polyvinyl Alcohol(PVA), adds assisstant agents and flow casting, after drying, forms final film. This paper studies key parameters of preparing biodegradable film from methyl corn starch blends with PVA, finds the best prescription. For future use and its effect on enviroment, further research of degradability , aging and gas barrier were made. Results are showed below.1 Through experiments, finds processing route and parameters of preparing different DS methyl starch. Condition for preparing DS=0.3 methyl starch is: temperature 500, starch susp. conct. 15%, DMSE: St (mol/mol) =0.005: 1,reaction time 2.5h.2 Best processing prescription for preparing methyl corn starch/PVA blends film is: methyl com starch DS=0.3, St/(St+PVA) (w/w) =0.50, glycerine/(St++PVA) (v/w) =0.10, formaldehyde/(St+ PVA) (v/w) =0.01, urea/(St+PVA) (w/w) =0.01, drying temperature of hot air is 65℃, heating time is 5h, and properties of film as tensile strength σ=14.27Mpa, elongation δ=158.93%, transparency T=78.3%, water sorption W=102.26%.3 Experiments of gas and oil barrier showed that methyl corn starch/PVA blends film can be used as package of oily and low moisture food.4 From hot air aging and radiation of ultravioletray, it indicates that methyl corn starch/PVA blends film can age under hot, oxygen and ultraviolentray. Properties of tensil strength, elongation, transparency, water sorption are all have different change, they are reducing.5 Experiments of double-enzyme degradation, microorganism eroding and soil bury indicate that film of methyl corn starch/PVA blends film is a kind of biodegradable material.6 This paper has innovation of using methyl starch as material for preparing biodegradable plastic film, and on the basis of ensuring film properties, sets out to raise content of starch and reduce usage of formaldehyde and glycerol.As data of the paper are all based on the careful experiments ,it can be used to industry availably,...