Research On Preparation And Properties Of Food Packaging Cellulose Film

Cellulose as the largest number of degradable regenerated organic material, is widespread in the nature. Compared with mineral resource such as oil, cellulose shows great environment friendly. Packaging film materials that are made of nature cellulose won’t cause of environmental pollution, as the waste of cellulose film will be biodegradation into CO2and H2O by microorganisms. It meet the requirement of low-carbon we vigorously advocating now days.N-Methylmorpholine-N-oxide(NMMO) as a new kind of cellulose solvent, has a strong solubility. It has high dissolution speed and low dissolution temperature, the mechanic properties is pretty good because of no degradation happened when dissolution. NMMO with a low toxicity that is weaker than alcohol, is stable when dissolving cellulose. The dissolving process won’t cause of environmental pollution and has a high recovery rate of99.7-99.9%. Selecting NMMO as the solvent, has greatly simplified the cellulose film production. The dissolution is totally physical process with no chemical reaction, what decrease the usage of raw materials and energy. That’s why it’s seen as a kind of "green method".The nature cellulose-made film properties are studied by different cellulose.In the single factor experiment, kinds of cellulose, cellulose content, coagulation content, coagulation temperature and plasticizer(glycerol) content are selected, the film properties are determined by tensile strength(TS), elongation at break(E), water vapor permeability(WVP), hydroscopicity(H), oxygen transmission rate(OTR), oil permeability(Po) and transmittance(T). The kinds of cellulose, cellulose content, and plasticizer content are determined that have significant influences on film properties, while coagulation content and coagulation temperature have less influence on the performance. Orthogonal experiment was selected to determine the producing condition for best film properties. The condition was cotton cellulose, cellulose content was6%, glycerol content was4%, and the film properties were:TS was4.764MPa, E was47%, WVP was2.58×10-7g·(m·s·Pa)-1, H was27.5%, OTR was4.98(cm3·mm)·(m2·d·0.1MPa)-1, Po was6.52g·mm·(m2·d)-1, T was85.3%.Chitosan has similar molecular structure with cellulose, NMMO was selected as the solvent of the two materials and a compound film was made from the two materials, which contains both the advantages of single films made of chitosan or cellulose individually. When mixing chitosan in, TS, E, OTR and Po had significant improved, while WVP, H and T showed a trend of decrease. According to response surface analysis, linear regression equations of TS, WVP, OTR and T about kinds of cellulose, cellulose content, and chitosan content were attained. By response surface methodology, the producing condition of best performance film was:cotton cellulose, cellulose content1.89%, and chitosan content0.50%. And the compound film mechanic properties were:TS was5.162MPa, WVP was3.50×10-7g·(m·s·Pa)-1, OTR was4.35(cm3·mm)·(m2·d·0.1MPa)-1, T was76.9%.The addition of starch acetate, sodium alginate and xanthan gum can improve the mechanic property of cellulose film significantly, while the addition of HPCMC, carrageenan and MC couldn’t improve the water barrier property of cellulose film significantly.