| Discarded plastic waste has become increasingly difficult to degrade naturally in recent years,causing serious environmental pollution all over the world.As a result,environmentally friendly materials,renewable resources,and sustainable technologies and techniques are gradually becoming the scientific and technological development trend.Cellulose materials have the advantages of having a wide source,a large storage capacity,being degradable and renewable,having a high strength,a high gas barrier,and having a high transparency after film formation,all of which have great potential in solving the environmental pollution and energy shortage that humans are currently facing.As a large agricultural country,a large amount of straw is either returned to the field or burned on the spot each year in China,resulting in a significant waste of straw resources.The effective development and rational use of straw is of great importance.In this paper,cellulose from corn stover was extracted and prepared into regenerated cellulose film,and the barrier property,mechanical property,optical property and microscopic property of the film were investigated;zein and gelatin（Gel）were combined with cellulose film by flow casting method,and heat-sealable RC/Gel and RC/Gel/Zein bilayer films were successfully made,and finally the bilayer films were applied to the packaging of oil to study its packaging effect,and the main research results are as follows:（1）Li Cl/DMAc（N,N-dimethylacetamide）was used as the solvent to investigate the effects of different extraction conditions on the dissolution of the obtained corn straw cellulose and the viscosity of the solution.As for the solubility,the corn straw cellulose gradually changed from a small amount of solubility to complete solubility as the particle size kept getting smaller;when the particle size was≤200 mesh,the corn straw cellulose was basically completely soluble.With the increasing concentration of alkali treatment,the solubility of corn straw cellulose became better and better;when the concentration of alkali treatment was≥10%,corn straw cellulose was completely dissolved.As for the solution viscosity,the viscosity of cellulose solution decreases continuously with the decrease of particle size;with the increase of alkali concentration,the viscosity of cellulose solution decreases rapidly and then tends to be stable gradually.（2）The regenerated cellulose films were prepared based on sol-gel method using corn straw cellulose as raw material and Li Cl/DMAc as solvent.The size of corn straw cellulose particle size,alkali treatment concentration and the type of coagulation bath will have a large impact on the performance of RC films.The effect of particle size and alkali treatment concentration on the performance of the films was more obvious,while the type of coagulation bath had less influence.The films prepared with 300 mesh particle size,10%alkali treatment concentration and aqueous ethanol solution as the coagulation bath had good overall performance and low cost,with tensile strength and elongation at break up to 101.2 MPa and23.37%,oxygen transmission coefficient and water vapor transmission coefficient up to 1.57×10-17 cm3.cm.cm-2.s-1.Pa-1 and 8.93×10-13 g.cm.cm-2.s-1.Pa-1,and the light transmittance and haze can reach 89.6%and 3.6%.（3）RC/Gel and RC/Gel/Zein bilayers were prepared by flow casting method using regenerated cellulose films as the substrate,and the effects of the casting concentration of Gel and the addition of Zein on various properties of the bilayers were investigated.As the casting concentration of Gel increased,the tensile strength and barrier property of RC/Gel bilayers decreased slightly,but the heat seal strength increased significantly.The moisture barrier and heat seal strength of the bilayer film were improved by adding Zein.20%of Zein content showed good overall performance,and the tensile strength,oxygen transmission coefficient,water vapor transmission coefficient and heat seal strength were 93.8 MPa,4.125×10-17cm3.cm.cm-2.s-1.Pa-1,1.5756×10-12 g.cm.cm-2.s-1.Pa-1,8.943 N/15mm.（4）The RC/Gel and RC/Gel/Zein double-layer films were applied to the packaging of different oilseeds,and the oil preservation was evaluated by sensory evaluation,acid value and peroxide value,and the results showed that the acid value of soybean oil and black pig oil were reduced by 11.7%and 19%,and the peroxide value was reduced by 14.7%and 22%,respectively,compared with PE.Both double-layer films were effective in delaying the oxidative rancidity of the oil,which has some application value in the packaging of oil for convenience foods. |
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