Research On Biodegradability Of Poly(Vinyl Alcohol) Water Soluble Packaging Film

As a novel packaging material, poly(vinyl alcohol)(PVA) has caused widespread concern in domestic and foreign researchers due to physical properties of the good water solubility, transparency, etc. Thus,PVA is biodegradable and microbial degradation of PVA has become a hot research topic in the field of environmental science. Currently, many studies about PVA degradation at home and abroad was researched, but mostly was the study of degradation of PVA itself, seldom studied about PVA film overall degradation and no researched about additives effects on PVA degradation. Therefore, in order to research the biodegradability of PVA water soluble packaging film, this article researched the biodegradability of PVA in aqueous solution by measuring PVA degradation rate. And then the PVA film was produced according to the biodegradability best film formula and the performance of film was measured. The main research conclusion is as follows:(1) The PVA degradation bacterium was screened by using transparent circle experiments and obtained a strain PVA degrading bacterium which had the best biodegradability and named as XP-02, then identified as penicillium sp. by the microscope and morphological observation.(2) PVA initial concentration, nitrogen source, macroelement, culture temperature, fermentation culture medium volume, p H value, etc. was researched on the influence of penicillium degrading PVA. And the optimum fermentation conditions was obtained by the orthogonal experiment: the culture medium composition was PVA 1.0 g/L, yeast extract 1.5 g/L, ferrous sulfate 0.15 g/L, potassium hydrogen phosphate0.05 g/L, sodium chloride 0.05 g/L, magnesium sulfate 0.10 g/L, calcium chloride 0.05 g/L and p H value is 6.5 in 60 m L fermentation medium under 32℃.(3) The additives of PVA water-soluble film on the effect of penicillium degradation of PVA was researched and found that the best plasticizer was ethylene glycol, the best surfactant was sodium dodecylsulfate, the best emulsifier and release agent was tween-80. And then the orthogonal experiment results showed that the PVA degradation rate was highest when the combination of the conditions were PVA 1.0 g/L,ethylene glycol 0.10 g/L, tween-80 0.10 g/L, sodium dodecyl sulfate 0.15g/L. Converted to mass fraction, the study found that the degradation rate of the PVA water soluble film was the best when mass fraction of PVA,ethylene glycol, tween-80, sodium dodecyl sulfate and the water was 10%,1%, 1%, 1.5% and 86.5% respectively, and the degradation rate of the PVA can get up to 43.76%.(4) PVA water soluble packaging film has been prepared according to the highest degradation rate formula and water solubility, equilibrium moisture content, thickness, tensile strength, elongation at break and tear strength were researched, and the results showed that the related performance all accorded with the requirement of industrial production.