| Plastic products are widely used due to their light weight,high mechanical strength,water resistance and durability,chemical stability,and low manufacturing cost.However,due to the fact that traditional plastics are not easily degraded,the “white pollution” problem caused by this has brought more and more problems to the ecological environment.With great pressure,at the same time,raw materials for traditional plastics production mainly come from limited fossil resources.In order to solve resource and environmental problems,it is particularly important to develop degradable plastics.Starch natural biomass has a wide range of sources and good regeneration performance.It is an ideal raw material for the production of degradable plastics.In this experiment,corn full powder was used as the matrix,blended with PVA,supplemented with plasticizers,reinforcing agents,and cross-linking agents to improve the performance of the blend films,and the influence of each component on the performance of the blend film was studied.The formulation and process conditions of the blend membrane were optimized by orthogonal experiments.In the single plasticizer system of triethanolamine,the blend film was prepared with corn flour and PVA as the main matrix.The mass fraction of PVA had a significant effect on the properties of the blend film.The tensile strength of the blend film was increased with the increase of PVA content.Elongation at break,tear strength and homogeneity of the blended film all showed an upward trend.The water absorption,water vapor transmission rate and the degradation performance of the blended film decreased.The Young's modulus varied with the PVA mass fraction.constant.The plasticizer triethanolamine can improve the flexibility of the film,increase the elongation and water absorption of the film,and reduce the right-angle tear strength and Young's modulus.The tensile strength of the blend film is 14.08 MPa when the triethanolamine is 1.5 ml.The proper amount of CMC can improve the mechanical properties of the blend film,and the excess will significantly reduce the elongation at break.The crosslinker borax can improve the tensile strength and water resistance of the blend film.The extension of cross-linking time is beneficial to increase the tensile strength and decrease the water absorption.In the binary composite plasticization system composed of triethanolamine and sorbitol,polyethylene glycol 400,urea,ethylene glycol,propylene glycol and glycerol,sorbitol and ethylene glycol can significantly increase the tensile strength of the blend film.In thetriethanolamine-sorbitol-ethylene glycol triple plasticization system,a higher proportion of triethanolamine is favorable for promoting the crosslinking reaction,but the amount of borax is also more.Corn flour/PVA and agar were blended under the three-element plasticization system.The mechanical properties of the film were significantly improved,and the tensile strength was about 28 MPa.The strength,toughness,and water resistance were ideal.The amount of matrix affects the performance of the blend film.The tensile strength of the membrane is about 30 MPa when the amount of matrix is 5.5 g.From the microscopic morphology of the blend film,when the ratio of PVA in the system is high,the corn flour is well dispersed,and the dispersion and uniformity of the system are better.Degradation experiment showed that the degradation ability of PVA was lower than that of corn flour.Under the saturated humidity environment,the higher proportion of corn flour was,the more the blend film was susceptible to fungal attack,the better the degradation performance.Infrared spectroscopy showed that after corn full-flour is blended to form the film,a large number of free and associative hydrogen bonds in the starch molecular chain undergo substitution reactions,the number of hydrogen bonds is reduced,and the generation of ester groups is conducive to decrease the hydrophilicity of the film.The formation of the B-O bond indicates that borax has a certain degree of crosslinking. |
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