Preparation And Physical Property Of PPC/SPI Composite Film

The Poly(Propylene Carbonate)/Soy Protein Isolate composite film was prepared by extrusion,Poly(Propylene Carbonate)(PPC)and Soy Protein Isolate(SPI)were as raw material,and glycerol as a plasticizer.The prepared composite film had good thermal stability,excellent mechanical propertiey,biodegradability.The technology of the composite film was optimize,and its mechanical property,structural property,application were studied.The main results were as follows:The process of extrusing PPC/SPI composite film was suitable,and the composite film was uniform,without any clear boundaries or delamination.The different factors(PPC/SPI(w/w),glycerol concentration,ethanol concentration)had a significant effect on mechanical property,opacity,water resistance for PPC/SPI composite film.The increasing of for PPC/SPI(w/w)(1.0:1,1.5:1,2.0:1,2.5:1,3.0:1)could make the flexibility of film enhance,the opacity increase,water absorption of the composite film gradually become lower,the mass loss of the film be significantly reduced,glycerol concentration could make mechanical property improve,the opacity gradually increase,water absorption of the composite film lower,the mass loss of the film increase,and,with the increasing of ethanol concentration,the elongation at break increased significantly,the changes in the tensile strength,the Young's modulus and the opacity is not obvious,water absorption of the composite film lower,the mass loss of the film is stable,about 10%.With the orthogonal experiments,the optimal extrusion process conditions of PPC/SPI composite film were PPC/SPI(w/w)of 2.5:1,glycerol concentration of 30%ethanol concentration of 75%.The structure of PPC/SPI composite film were explored by thermodynamic characteristics analysis,thermal gravimetric analysis,scanning electron microscopy,fourier transform infrared spectroscopy.The results showed that PPC molecules and SPI molecules could be sufficiently mixed with crosslinking to form a composite film of good thermal stability and stability,dense uniform structure.At temperatures up to 250 ?,the film remained stable.In certain relative humidity,PPC/SPI composite film's application were studied.The experiment indicated that moisture contents of composite film positively changed with different humidity,and with increasing humidity,the tensile strength of the film gradually reduced,the elongation at break of the film increased.