再生丝素蛋白/聚乙烯醇共混取向纳米纤维膜的制备与性能

Preparation and properties of regenerated silk fibroin/polyvinyl alcohol blended nanofiber membranes with predesigned orientation

为进一步提升取向纳米纤维膜在纺织生物医学领域的应用潜力,以再生丝素蛋白(RSF)和聚乙烯醇(PVA)为原料,通过静电纺丝制备取向纳米纤维膜。通过单因子及正交试验确定最优纺丝参数,并对取向纳米纤维膜的形貌、化学结构、力学性能、热稳定性能等进行研究。结果表明:静电纺丝最优纺丝参数为选甲酸为溶剂,滚筒转速2400 r/min,纺丝液质量浓度0.16 g/mL,纺丝电压23 kV,出液速度0.6 mL/h,接收距离17 cm;RSF与PVA之间存在一定相互作用,使RSF中部分无规结构向α螺旋结构转变;与相同纺丝时间下得到的无取向纳米纤维膜相比,取向纳米纤维膜的特点为断裂强力更高,是无取向纳米纤维膜的2倍以上,孔径更大,集中在0.5μm附近;取向结构对纳米纤维膜热稳定性基本无影响。

Objective Non-oriented nanofiber membranes are usually obtained on the receiving device due to instable movement of polymer jet in electrospinning.Oriented nanofiber membranes are obtained by changing the receiving device and other methods.Compared with non-oriented nanofiber membranes,oriented nanofiber membranes have the advantages of regular fiber arrangement and good mechanical properties.The paper proposes the preparation of oriented nanofiber membranes by electrospinning with regenerated silk fibroin(RSF)and polyvinyl alcohol(PVA)as raw materials,and potential applications of oriented nanofiber membranes in the field of textile biomedicine.Method The optimal spinning parameters were determined by single factor experiment and orthogonal experiment,and the morphology,chemical structure,mechanical properties,thermal stability,pore size distribution of oriented nanofiber membranes were studied with the assistance of scanning electron microscopes,Fourier transform infrared spectrometer,medical multi-function strength tester,synchronous thermal analyzer,and porous material pore size analyzer.Results Based on the nanofiber membrane morphology obtained from single factor experiment and orthogonal experiment(Fig.1,Tab.2 and Fig.2),it was evident that the optimal electrospinning parameters for preparing RSF/PVA blended oriented nanofiber membranes were as follows,formic acid as the solvent,roller speed of 2400 r/min,spinning fluid concentration of 0.16 g/mL,spinning voltage of 23 kV,outflow velocity of 0.6 mL/h,and receiving distance of 17 cm.Under these parameters,the oriented nanofiber membranes demonstrated regular morphology and high orientation(Fig.3 and Tab.3).It can be seen from the infrared spectra of RSF power,PVA grain and RSF/PVA oriented fiber membranes(Fig.4)that compared with RSF powder,part of amorphous structure in the oriented nanofiber membranes was transformed into theɑhelix structure.The stretching effect of the high-speed roller on the fiber was conductive to improving the degree of orientation and crystallinity of nanofiber membranes,thus the breaking strength of the oriented nanofiber membranes obtained under the same spinning time was more than two times that of the non-oriented nanofiber membranes,but the elongation rate at break was lower than that of the latter(Tab.4).The oriented and non-oriented nanofiber membranes almost coincide,and both begin to decompose at 284℃with their thermal decomposition rates fastest at 312℃(Fig.7),indicating that the thermal stability of the oriented and non-oriented nanofiber membranes was similar,and the stretching and alignment of fibers by the high-speed roller had substantially no effect on the thermal stability of RSF/PVA nanofiber membranes.The pore sizes of oriented and non-oriented nanofiber membranes were distributed in 0.46-1.50μm and 0.08-0.48μm,respectively,and were concentrated near 0.5μm and 0.1μm,respectively,indicating that oriented nanofiber membranes had larger pore sizes and were expected to be used in the field of textile biomedicines.Conclusion RSF and PVA were electrospinned into oriented nanofiber membranes.The optimal spinning parameters were determined by single-factor experiment and orthogonal experiment,and the morphology,chemical structure,mechanical properties and thermal stability of nanofiber membranes were studied.The experimental results showed that part of the amorphous structure in the oriented nanofiber membranes was transformed into theɑhelix structure;and the oriented nanofiber membranes had higher strength than the non-oriented nanofiber membranes,but had lower elongation at break under the same spinning time.And the pore sizes in the oriented nanofiber membranes were larger than that of the non-oriented ones and the oriented structure has substantially no effect on the thermal stability of the nanofiber membranes.The experimental results provided a theoretical basis for further enhancing the application potential of oriented nanofiber membranes in the field of textile biomedicine.