Study On Acrylamide Modified Corn Starch/Polyvinyl Alcohol Composite Film

As a polymer material that can be degraded by microorganisms,polyvinyl alcohol(PVA)is widely used in plastics because of its good water solubility and film-forming degradability,and the degradation products do not pollute the environment.Packaging field.However,the mechanical properties and water resistance of the pure PVA film are poor,which severely limits its application.Therefore,in order to improve the mechanical properties of the PVA film and expand its application range,this paper selects the common degradable edible corn starch as the raw material,and explores the different monomer ratios of corn starch and acrylamide,the addition of different initiators,and the difference The acrylamide modified corn starch x ST-y APSU was prepared under the conditions of reaction temperature and reaction time.Through single-factor experiments,the optimal synthesis conditions for acrylamide-modified corn starch are determined as follows: the mass ratio of starch/acrylamide is 3:7,the initiator ammonium persulfate accounts for 0.5% of the total monomer mass,and urea accounts for the monomer.0.5% of the total,react at 50°C for 4hours.In addition,a series of x ST-y APSU/PVA composite films were prepared by blending the prepared modified starch as raw materials with PVA.The composition and structure of the composite films were characterized by Fourier infrared spectroscopy and scanning electron microscope(SEM),and the composite films were measured at the same time.The mechanical properties,water resistance,heat resistance and other physical and chemical properties of the film.The results showed that the monomer conversion rate of 30%ST-0.50%APSU modified starch was 95.0%,and the grafting rate was 85.2%.The heat resistance of30%ST-0.50%APSU/PVA composite film is slightly reduced,but the elongation at break is increased by 256% compared with pure PVA film,and the water resistance is increased by43.1%.Furthermore,the degradation test of the composite film was carried out,and the results showed that the p H environment had almost no effect on the degradation rate of the composite film;the soil burying degradation experiment showed that the composite film has good biodegradability,and the degradation rate varies with the starch content in the composite film.Increase and increase,and the degradation rate of 50%ST-0.50% APSU-type starch/PVA composite film reaches 75% within 120 days.