Preparation Of Regenerated Cellulose Films From Corn Stalk NaOH-AQ Pulp Fines

Cellulose is the most abundant renewable organic raw materials in the earth,which has a wild application because of the characters of biocompatibility and biodegradability.China has been the largest agricultural county in the world,nearly 900 million tons of crop stalks are produeced yearly.On the contrary,forest resources are relatively deficient in China.Threrefore,huge storage of agricultural straw resources become the most potential resource of cellulose.Corn stalk has not be utilized for their huge number of parenchymal cell in the stalk pith.High yield corn stalk pulp can be obtained,through adjusted the conditions of pulping.Meanwhile,the quality of pulp canbe improved by screened and separated the fines?parenchyma cells?.The parenchyma cells can be obtained and utilized as a new cellulose resource.In this paper,the fines of NaOH-AQ corn stalk pulp was used as a resource of cellulose to prepared regenerated cellulose films using ZnCl₂solution and DMAc/LiCl solution.Corn stalk pulp was prepared under NaOH-AQ cooking method,the screened pulp yield was46.83%,Kappa number was 12.95 and viscosity was 1150 mL/g.The study found that the viscosity and fiber length of corn stalk pulp was improved after 120-mesh screen seperation.Furthermore,the mechanical properties of separated pulp were overall performance than that of the intital pulp.The regenerated cellulose film was prepared using ZnCl₂ solution from corn stalk pulp fines and corn stalk pith cellulose.The concentration of ZnCl₂ solution was successfully decreased under 65%.The study found that low dosage of dissolving solution was took an advantage effect on the mechanical properties?maximum tensile strength 32.27 N?m/g?of regenerated cellulose film.In addition,the crystallization index and thermal stability of films was increased as the usage of dissolving solution decreased.The results indicated that regerated cellulose materials with thermal stability controllable can be obtained through adjusted their index of crystallization.Regenerated cellulose films were prepared using LiCl/DMAc solution from corn stalk pulp fines and corn stalk pith cellulose.The study observed that the transmissivity of regenerated film was high.Meanwhile,the regenerated films showed crystallization characteristics of cellulose II.The results indicated that the integrity of parenchyma cells has a great affect on the mechanical properties of regenerated cellulose films.Thermal stability of regenerated films prepared by LiCl/DMAc was better than that of prepared by ZnCl₂ solution.Mechanical properties of regenerated cellulose films which intital cellulose was obtained in 120²00-mesh was the best.XRD spectra showed that the crystallization index of films and the ratio of cellulose II was increased followed the sizeof cellulose particle decreased,however,the thermal stability and surface hydrophobicity of films was decreased.The results indicated that parenchy cells were more suitable for dissolution than fibers.The behavior of cellulose dissolution and the properties of regenerated cellulose films was mainly affected by their particle size.Graphene oxide?GO?and black phosphorus?BP?were used as additives for prepared mechanical properties enhanced regenerated cellulose films using ZnCl₂ solution and DMAc/LiCl solution in this study.The results showed that the GO was embedded into the regenerated cellulose in sheets,the mechanical properties have been improved greatly?the tensile strength was increased62.7%and 22.20%?,in contrary the thermal stability of films was dedcreaed to 220.5°C?ZnCl₂system obtained?and 305.4°C?DMAc/LiCl syatem obtained?.In contrary,the films additived with BP showed different characters compared with the GO composited films.The thermal stability of films was dedcreaed to 219.6°C?ZnCl₂ system obtained?and 309.6°C?DMAc/LiCl syatem obtained?with the BP addition.The enlongation of RC films were improved in both dissolutions when the usage of BP was increased,meanwhile,the water contact angle was decreased.This study indicated that the addition of GO and BP were sure can enhanced the mechanical properties of the cellulose fines regenerated cellulose films.