Structure And Properties Of Cellulose Acetate Nanocomposite Electrospun Fiber

Cellulose acetate(CA)is an important bio-based polymer widely used in fields as membrane materials,apparel industry,tissue engineering and other fields.It normally plays a role as a spinning matrix in electrospinning because of its excellent spinnability.After modification,CA can be electrospun to obtain nano-composite fibers with different properties.Based on the spinning conditions and physical modification methods of CA electrospun nanofibers,the research is operated through the following three aspects:(1)Exploring the effect of CA concentration and spinning voltage intensity on the morphology and structure of nanofibers.The spinning voltage and concentration were adjusted for electrospinning,and the electrospun samples were characterized by a series of methods such as SEM,EDS,FTIR and XRD.The results show that with the increase of CA concentration,the diameter of electrospun fiber increases gradually;with the increase of spinning voltage,the diameter of electrospun fiber reached to the peak before decrease.When the solution concentration was 15 wt.% and the spinning voltage was 17.5 kV,the obtained nanofibers were uniform and dense,which was determined to be the optimum electrospinning condition.At the same time,it was found that the CA fiber obtained by electrospinning changed from hydrophilic(60~80°)to hydrophobic(95~125°),and its water contact angle decreased with the increased porosity of the CA fiber.(2)Exploring the morphology and properties of petal-shape Mg-based flame retardant /CA nanocomposite electrospun fibers.The two petal-shape Mg-based flame retardants were prepared by precipitation: basic magnesium carbonate(MgO-P)and magnesium oxide(MgO),were all blended with CA at different concentrations and electrospun under the spinning conditions in(1).The nano-composite fibers were characterized by XRD,SEM,EDS,HRTEM,FTIR,TGA,flame retardant test and other characterizations.The results show that the flame retardant performance of the composite fiber was enhanced with the increase of the concentration of the flame retardant.When the concentration of flame retardant is 3 wt.%,the flame retardant effect of MgO-P/CA and MgO/CA fiber is increased by 26.3 and 23.5 times,respectively.After rising the concentration of the flame retardant,the fiber becomes brittle and it is difficult to remove a complete film from the aluminum foil.(3)Exploring morphology and properties of cellulose nanocrystal(CNC)/CA nano-composite electrospun fibers.The CNC is blended with CA at different concentrations,and the electrospun nanocomposite fiber is obtained under the electrospinning condition of(1).The samples were tested by rheological test,HRTEM,SEM,XRD,FTIR,TGA,mechanical test,etc.The results show that with the increase of CNC concentration,the mechanical properties of nano-composite fibers were strengthened at first but then decreased.When the concentration of CA is 0.105 wt.%,the fracture stress of the fiber is 5.72 MPa at the maximum,which is 2.8 times higher than that of CA nanofiber;the fracture strain of the fiber is 2.47 % at the maximum,which is 2.2 times higher than that of CA nanofiber.