Study On The Dissolving And Film-Forming Properties Of Flax Cellulose

With the promotion of sustainable development strategy and the enhancement of environment-tal protection awareness,cellulose has attracted more and more attention because of its good biocompatibility and degrdability.Flax has a wide planting area and abundant resources in China.At present,flax is mainly used in clothing fabrics,automobile supplies and bedding,etc.,and there is little research on flax fiber dissolution and film formation.The study on cellulose dissolution and film-forming properties of flax is of great significance to improve the utilization rate of flax natural fiber and broaden its application fields.This topic mainly explores the dissolution and film-forming technology and performance test of flax cellulose.Flax fiber was selected as raw material,and zinc chloride aqueous solution with a certain concentration was used as solvent to dissolve it.The solution was formed by salivation,then immersed in water coagulation bath and gelatinized.Polyvinyl alcohol（PVA）as additive and flax fiber as reinforcing matrix were added in the film preparation process,and then dried and shaped in oven to obtain PVA/flax fiber membrane.The performance test and process optimization were carried out.In the dissolution process,the effects of ZnCl₂concentration,flax fiber mass fraction,dissolution time,dissolution temperature,shear action and storage time on the dissolution and stability of cellulose solution were investigated.The results showed that with the increase of ZnCl₂concentration,the solubility of ZnCl₂to cellulose was enhanced gradually.When the concentration of ZnCl₂was 67%,it showed good solubility to cellulose.The cellulose solution obtained by the mass ratio of 2%flax cellulose to solution has good fluidity and viscosity.The stability of flax cellulose solution was significantly affected by dissolution time and temperature.The viscosity of cellulose gradually stabilized after dissolution for 4 hours.At 90℃,cellulose had good dissolution efficiency.The viscosity of cellulose solution will decrease with the increase of the shear force,and the cellulose solution system will be affected by the environment during storage,resulting in deterioration.The observation results show that the best use time of cellulose solution is within 4days.In the part of film forming process,the effects of degree of fibre dissolution,additive mass fraction,fiber length and drying temperature on tensile properties,bending properties and air permeability of cellulose film were investigated by single factor analysis.Secondly,using orthogonal design method,the preparation of PVA/flax cellulose membrane orthogonal experiment,through the range and variance analysis to optimize the optimal scheme,and validation experiments.The results of single factor experiment show that,With the increase of PVA mass fraction,the breaking strength of PVA/flax fiber membrane increases,When the length of flax fiber,drying temperature,the mass percentage of flax fiber/dissolved part fiber and the mass fraction of PVA reach the optimum value,When the length of flax fiber is 2mm,the drying temperature is 90℃,fibre dissolution time is 4h,and the mass fraction of PVA is 3.9%,the PVA/flax fiber membrane has good breaking strength,bending rigidity and air permeability.According to the results of single factor analysis,the appropriate process parameters were selected,and the orthogonal experiment was carried out on the preparation process of PVA/flax fiber membrane.The range analysis and variance analysis were carried out on the experimental results,and the best experimental scheme was selected.Considering that the breaking strength of PVA/flax fiber membrane has great influence on its properties,the results show that the optimum preparation process of PVA/flax fiber membrane is drying temperature 80℃,fibre dissolution time4h and PVA mass fraction 6%.In addition,the surface friction properties,compression softness and shear properties of PVA/flax cellulose membrane were studied.The results show that the composite membrane prepared in this paper has good tensile and shear properties and good softness.