Preparation Andapplication Of Cellulose Derivatives Composites Prepared From Solidago Canadensis

As the demand for quality of life rises and as the county is evolving from manufacturingfocused to value added industry, the sustainable development is becoming the most importantstrategy for long-term development of human being. Cellulose is one of the most promisingnatural renewable resources with wide distribution and the largest reserves in nature. It has beenrecognized as a main feedstock for energy and petrochemical industry, which is the environmentalfriendly method combined the strength of biocompatibility and controllable surface properties.Since the restriction of forestry resources as a main resource of natural cellulose, it is becomingincreasingly important for extracting cellulose from herbaceous plants rich in resources. Celluloseand its derivatives has been widely used in preparation of membrane material due to the low cost,simple process and unique physic-chemical properties.In this paper, we use the Solidago Canadensis as raw material for preparation of celluloseacetate (CA) and acetate based composite by using the formic acid/hydrochloric acid processingmethod and glacial acetic acid/sulfuric acid processing method. The performance of thecomposites were measured and correlated with the physic-chemical properties of thecorresponding samples. This method can be used to preparation of functional material, and alsosupport the environmental protection and biological invasion.(1) Cellulose acetate (CA)/polylactic acid (PLA) composite membrane were synthesizedthrough in-situ mixture of CA and PLA in DMF solution by Loeb-Sourirajan (L-S) phaseinversion process. The effect of PLA content on the performance of composite membrane wasfurther characterized by scanning electron microscope (SEM), infrared spectroscopy (IR),thermogravimetric analysis (TGA), and correlated with the bibulous rate, permeability, wettingability, and mechanical properties. Not only the morphology and texture structure but also the of wetting ability, and mechanical properties of composite membrane were shown to vary with thePLA variation. The IR show that there is no perceptible change in the surface group and hydrogenbond structure with PLA added. The compatibility of CA and PLA seemed to have great impact onthe surface structure of composite membrane, and when the content of PLA was at relative lowlevel, a smooth and tight surface was observed through SEM image. The results of wetting andmechanical assessment demonstrated that the addition of PLA would give rise to improvement inwater resistance and decline in thermal stability. The maximum mechanical properties and lowestpermeability were generated from a certain amount of PLA (15wt.%) in the composite.(2) Polyvinyl butyral (PVB)/cellulose acetate (CA) composite membrane with PVBdifferent concentration was prepared by the method of immersion-precipitation phasetransformation. The as-prepared blend membranes were characterized using scanning electronmicroscopy (SEM), mechanical analysis, contact angle, pure water flux (PWF), rejection andporosity to understand the influence of polymer blend composition on the properties of themodified membranes. SEM analysis showed that PVB/CA blend membranes possessed large sizepore in the top layer and porous structures in the cross-section. The results also showed that CAhad certain compatibility with PVB under the condition of low concentration of PVBA. Theproperties of PWF, rejection, porosity and mechanics performance were improved by the additionof PVB with lower WPVB values, especially at about0.2.(3) PVB/CA membranes blended with polyethylene glycol600(PEG600) and polyvinylpyrrolidone (PVP) for improving the PWF and hydrophilicity were prepared in a L-S phaseinversion process, respectively. PEG600and PVP (K30) were used as additive. The effect ofadditive conservation on the composite membrane performances were investigated. The resultsindicated that the PWF and hydrophilicity were enhanced, significantly. The PWF went up and theBSA rejection ratio were depicted with increasing of PEG600contents in the solution. The PWFwas only35.42L m-2h-1for PVB/CA blend membrane without additive (PEG600); however, itdramatically increased to95.67L m-2h-1and82.21L m-2h-1when PEG600and PVP(K30) ratioreached10wt.%, respectively. The BSA rejection ratio were depicted from86.27%to33.72%andthe porosity ranged from53.45%to84.21%with increasing of PEG600contents in the solution,while the BSA rejection ratio had small changes with increasing of PVP(K30) contents. Theporosity ranged from53.45%to78.47%when PVP(K30) ratio increased from0to4wt.%,however, it was decreased to65.32%with PVP(K30) ratio reached10wt.%. Therefore, PVP (K30)was more suitable additives for PVB/CA blend membrane.(4) The effect of polyacrylonitrile (PAN) on the structure and performance of PAN/CAcomposite membrane was investigated in the solution of DMSO. The SEM image illustrated thatmorphology and performance of composite membrane can be modulated by selecting PAN amount. The composite membrane with more PAN amount provided higher aperture and porosity,and an improvement in water permeability, wetting ability. However, there existed a maximumvalue of rejection ratio which was achieved at the92.4%, and decreased markedly as the PANamount exceeded70%.(5) It has been widely accepted that nano-SiO2can be used as effective additive for PAN/CAcomposite membrane due to the high specific surface area and low surface energy. The existenceof nano-SiO2would improve the viscosity of the mixture, which result in an enhancement ofwetting ability and mechanical properties of the composite. An absolute improvement in porosity,water flux, rejection ratio as well as the resistance to pollutant was observed in the experiment.However, when the nano-SiO2concentration further increased to10%, the agglomeration ofnano-particles occurred, causing a decline in aperture and porosity as well as the water flux.Therefore, nano-SiO2should be controlled in the certain range so as to obtain the paramountperformance.