Study On The Modification And Preparation Of Chitosan/Hydroxypropyl Methyl Cellulose Packaging Film

In this paper, the chitosan/hydroxypropyl methyl cellulose film, a renewable and degradable packaging material, was prepared.There was little studied on the properties of chitosan/hydroxypropyl methyl cellulose blend film inland. The film was prepared by co-solution. The prescriptions and processing were optimized. The effect of glycerol, polyethylene glycol and glutaraldehyde were studied on mechanical properties, optics properties, water absorption and oxygen permeability of this film, and SiO2 toughened this film and adjusted its oxygen permeability.The main conclusions in this paper were as follows:The compatibility between chitosan and hydroxypropyl methyl cellulose was studied by FTIR, XRD, AFM, TG and DMA. The hydrogen bonding interaction between the two components was the strongest when the volume percentage of HPMC was 40%. By tensile testing, HPMC had a toughening effect on chitosan film when the volume percentage of HPMC was above 40%. The best prescription of the blend film was that the mixture ratio of chitosan and HPMC was 60:40, the concentration of the blend solution was 1% and that of the solvent acetic acid was 0.5%. The best processing was that stirring time of the polymeric solution was 1±0.5h, stirring temperature was 30±5℃and film forming temperature was 25～50℃.Glycerol and PEG, as plasticizers, could improve the blend film and made its integrated performance better. As the content of glycerol was about 0.02%～0.08%, its mechanical properties reached better(tensile strength had a little alteration, about 60MPa, breaking elongation increased by a half time, up to about 40%). When the content of glycerol was about 0.33%, its optical property was all right. As such, as the content of PEG was about 0.83%, the mechanical properties of the film was better (tensile strength decreased by 0.7 times to 23MPa, breaking elongation increased by 1.2 times, to 66%). When the content of PEG was about 0.5%, optical property all right. Comparing the two plasticizers, the plastification of glycerol was better.Fourier transform infrared(FTIR) analysis of chitosan/hydroxypropyl methyl cellulose blend film with glutaraldehyde as crosslinking agent indicated that there was crosslinking reaction between glutaraldehyde and the blend film and new chemical bond [C=N] produced, which improved its integrated performances. The degree of crosslinkage increased, tensile strength of the blend film decreased while breaking elongation increased as glutaraldehyde was added. When the range of volume fraction of glutaraldehyde was between 1.33% and 1.67%, its mechanical properties was very good. For the blend film after crosslinking, the water-resistance increased, the blend film becomed yellow and light transmittance reduced.The inorganic nanoparticles SiO₂ was prepared by adding tetraethoxysilane to the film forming solution, which properly adjusted oxygen permeability of the blend film and enlarged its application in the packaging materials field.