Study On Properties Of Zein Film Treated By Low Temperature Plasma And Grafted PLA

In this paper, the zein film was modified by low temperature plasma after the zein was dissolved in 80% ethanol aqueous solution, and the plasma was treated with different treatment power (30W,50W,70W) plasma after treatment,the surface of zein film was rough but the main structure is not destroyed. After treatment, the hydrophilicity of the film was improved obviously,and the contact angle decreased from 65.37° to 45.71° with the increase of treatment power. The tensile strength and elongation at break the water vapor transmission rate decreased from 4.57× 10-8 g · m / m2 · h · Pa to 3.55×10-8 g · m / m2 · h· Pa; the denaturation enthalpy did not change obviously; the atomic force microscope results show that the surface roughness increases from 3.45 nm to 75 nm, and the FT-IR and X-ray diffraction analysis show that the plasma treatment reduces the order of the protein. The surface hydrophilicity and roughness of the zein film can be improved by adjusting the plasma treatment power, which provides a basis for further study on the application properties of zein film.The results of the first part show that the hydrophobicity of the films modified by by low temperature plasma. The grafted modification by low temperature plasma Grafted polylactic acid to improve the hydrophobicity of the zein film and to study the properties of grafted modified film. The single factor test was used to determine the grafting conditions of grafted polylactic acid, the grafting pretreatment power of 50W, the grafted polylactic acid concentration of 0.6g / L and the grafting time of 30min had better hydrophobicity .The grafting time had a significant effect on the hydrophobicity of the modified films by orthogonal experiment.The grafting time was 10min, 30min, 50min and 70min, and the grafted modified zein film was compared with the original unmodified zein film. The water resistance of the modified films was improved, and the properties of the modified films was stable under the condition of large change of external humidity. The mechanical properties of the modified films shows that the tensile strength of the modified films does not change significantly, but the plasticity of the films is improved. The results of DSC and TGA shows that the thermal stability of the modified films is improved, and the stability is improved. The scanning electron microscopy (SEM) observation showed that under the action of low temperature plasma, when the grafted polylactic acid was over 30min, close integration and the cross section was uniform. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) shows that the zein membrane and polylactic acid have good bonding under the action of low temperature plasma.