Preparation And Application Research Of Electrospun CNW/PLA Composite Nanofiber Membranes

Currently various methods have been used to improve the preservation of fruit andvegetable such as cold storage, air conditioning, radiation and so on. But the high cost andcomplicated operation of these methods are obviously drawbacks that have to be overcome.Nanofiber membranes produced by electrospinning have showed exceptional characteristicssuch as high porosity, small pore size and large area-to-volume ratio, so they are found havingoutstanding barrier property, which suggest that electrospun nanofiber membranes have greatpotential application in the field of preservation of fruit and vegetable.In this paper, CNW/PLA composite nanofier membranes were prepared byelectrospinning technology. Homemade CNW was characterized with Transmission electronmicroscope (TEM)，Fourier Transform infrared spectroscopy (FTIR) and X-ray diffraction(XRD). The surface morphology and diameter of electrospun nanofibers were analysed usingscanning electron microscopy (SEM) and Photoshop software；FTIR and XRD analysis werecarried on to investigate the influence of CNW on the microstructure of electrospunCNW/PLA composite nanofibers. Mechanical property, pore size distribution and wettingproperty of electrospun PLA nanofiber membrane and electrospun CNW/PLA compositenanofiber membrane were also tested and analyzed. The antibacterial properties ofelectrospun CNW/PLA composite nanofiber membrane were tested using modified oscillationflask method. Furthermore, strawberries were packaged with electrospun PLA nanofibermembranes, electrospun CNW/PLA composite nanofiber membranes and PE film to study theeffect of electrospun CNW/PLA composite nanofiber membrane on the preservation ofstrawberries. The decay index, weight loss, titratable acidity content and VC content of thepackaged strawberries were characterized. The following conclusions were drawn throughthis research:(1) Homemade CNW was baculiform or needlelike, and dispersed very well in thesolution, providing the prerequisite for the preparation of eletrospun CNW/PLA compositenanofiber membrane. The concentration of PLA and CNW has significant effects on themorphology and diameter of electrospun nanofibers. The optimal concentration of PLA is8%,and when the CNW content was in the range of1%～7%， nanofibers with smooth surfaceand uniformity could be obtained. SEM images showed that the diameter of electrospunCNW/PLA composite nanofibers was between500nm to1200nm.(2) CNW was successfully embodied in PLA nanofiber, and no chemical reaction tookplace.(3) The addition of CNW significantly improved the wettability and permeability of thePLA nanofiber membrance, but enlarged the proe size and broadened the pore distribution.The tensile test results indicated that embodiment of CNW in PLA nanofiber can significantlyimprove the mechanical properties of PLA nanofiber when the content of CNW is below3wt%, but higher content of CNW would weaken the reinforcement effect and even brought anegative effect. (4) With the increasing content of CNW in the eletrospun CNW/PLA compositenanofiber membranes, the inhibitory rate against Escherichia coli and Staphylococcus aureusincreased progressively. When the percentage of CNW increased to7%, the inhibitory rateagainst Escherichia coli and Staphylococcus aureus reached to94.5%and91.7%,respectively.(5) Eletrospun CNW/PLA composite nanofiber membrane could decrease the decayindex and weight loss, delay the decline of titratable acidity and vitamin C contents.Meanwhile, the antisepsis preservation of eletrospun CNW/PLA composite nanofibermembrane on the strawberries was very obvious.