【作者】 王立新；

【导师】 张幼珠；

【作者基本信息】 苏州大学 ， 纺织材料与纺织品设计， 2009， 硕士

【摘要】 采用静电纺丝技术能够得到直径从几十纳米到几微米的连续的纳米纤维,是制备超细纤维的一种主要方法。纳米纤维具有直径小、比表面积大、孔隙率高等特点,因而具有广泛的应用,可作为组织工程支架及生物医用材料。论文选择了PLA、PLGA及丝素三种生物可降解材料进行静电纺丝,并对各自的降解性能进行了详细研究。通过纤维膜的失重率、相对分子质量、断裂强度的变化以及SEM观察其降解过程中形貌的变化;再通过X射线衍射和DTA测试降解过程中的结晶度变化,来表征三种纤维膜的降解性能。PLA静电纺丝工艺条件本课题组已有研究,在此基础上制得PLA纤维膜。再将其浸入到PBS溶液中进行降解。降解前两周相对分子质量下降率明显快于失重率,断裂强度逐渐下降,降解16周时纤维粗细不匀,并出现少许断裂。降解过程中,样品结晶度不断下降。在PLGA纤维膜降解性能研究之前,首先研究了PLGA质量分数、电压和极距对所制得纤维形态结构的影响,确定较优工艺条件为:质量分数7%,电压20kV,极距13cm。在较优工艺条件下制得PLGA纤维膜,然后浸入到PBS溶液中进行降解。PLGA纤维膜降解速度快于PLA纤维膜。两周时相对分子质量下降率和失重率快速增加,但失重率仍滞后于相对分子质量下降率,此时纤维已经出现少许断裂,断裂强度快速减小。10周时纤维形态消失,样品变得硬脆并崩解成小碎片。X射线衍射和DTA测试发现PLGA纤维膜降解前后都为无定型聚合物。静电纺丝素纳米纤维膜在PBS溶液体外降解过程中,质量损失非常缓慢,力学强度下降小,通过电镜观察随着降解时间的延长,10周时纤维大量断裂。红外光谱测试发现静电纺丝素纳米纤维膜乙醇处理后主要以β折叠构象为主,随着降解时间的延长出现无规卷曲,并逐渐增多。更多还原

【Abstract】 The electrospinning technique is one of the most important methods of producing continuous nanofibers with diameter range from several micrometers to tens of nanometers. With small diameter, high surface area to volume ratio and high porosity, nanofiber can be used in tissue engineering and biomedical engineering.In this paper, three degradable materials, PLA、PLGA and SF(silk fibroin) were elected to electrospin and studied on the degradation of them detailedly. Through the membranes of the weight loss, molecular weight, breaking intensity and SEM observation of the changes in morphology, meanwhile through X-ray diffraction and DTA testing in the process of degradation of crystal changes, the degradation of three types of fiber membranes performance were characterized. Our group has studied the conditions of electrospun PLA, PLA membranes were obtained on this basis,and then immersed in PBS solution to degradate. The molecular weight of the first two weeks declined significantly and faster than the rate of weight loss and breaking intensity. The fibers were uneven and broken in the degradation of 16 weeks. During the degradation process, crystal of samples decreased gradually.Before studying the degradation of PLGA membrane, firstly, the effect of concentration、voltage and distance on the morphology and structure of the PLGA fibers were studied. The optimum conditions were as follows: the concentration of 7%, voltage 20kV, distance 13cm. PLGA membranes were immersed in PBS solution to degradate.Degradation of PLGA membranes was faster than PLA membranes. There is a rapid increase in weight loss and the molecular weight reduction in two weeks, but the weight loss rate is still lagging behind the decline in the molecular weight reduction. At the same time, the fibers have been some fracture, breaking intensity decreased rapidly. The fibers disappeared in the10 weeks; the sample had become hard, brittle and small pieces. X-ray diffraction and DTA tests found that PLGA fiber membranes were amorphous polymer before and after degradation. In vitro degradation process of electrospun SF membranes in PBS solution, the weight loss was very small and the breaking intensity declined slowly.SEM observed that a large number of fibers broke in 10 weeks. IR test found that electrospun SF membranes after ethanol post-treatment were mainlyβ-sheet structure, random coil emergenced and increased gradually with the degradation time.更多还原