【作者】 肖斌；

【导师】 李从举；

【作者基本信息】 北京服装学院 ， 材料学， 2008， 硕士

【摘要】 本文首先研究了聚乳酸(PLA)的电纺,系统研究了PLA电纺过程中的影响因素。结果表明,当溶剂为二氯甲烷(DCM)和N,N-二甲基甲酰胺(DMF)的混合溶剂时,可以形成良好的聚乳酸电纺溶液体系;DCM与DMF以体积比8:2或者7:3混合都是PLA电纺比较理想的溶剂配比;接收距离对电纺纤维直径的影响与浓度有关,对于PLA溶液,随着接收距离的增大电纺纤维直径变小,而接收距离小于10cm时,电压的增大有利于超细纤维的形成;电压变化在9kV～22kV时都可纺丝,随着电压的增加,纤维的直径变小,电压过高纺丝过程不稳定;纤维直径对PLA电纺纤维膜的力学拉伸性能影响很大,随着纺丝液浓度的增大,PLA电纺纤维膜的拉伸强度先增大然后又减小,电压的增大使得PLA电纺纤维膜拉伸强度下降,而分子量的提高则拉伸强度增加。根据对聚乳酸电纺的研究,我们将纳米磷酸钙(NCP)掺加到聚乳酸(PLA)中通过静电纺丝法制备了生物医用复合纳米纤维以及利用新型电纺法制备具有排列取向的复合纤维。配制一系列质量浓度为7%的聚乳酸溶液,然后依次掺加0,1%,3%,5%,7%,9%,11%和13%的磷酸钙进行静电纺丝。其中掺加磷酸钙的量为聚乳酸质量的百分比。透射电镜(TEM)表明,磷酸钙成功地掺加到了聚乳酸纤维当中;扫描电镜(SEM)结果表明,磷酸钙掺加浓度在7%之前,纤维形貌没有很明显的变化,但是随着浓度的增大,纺丝状态开始变得不稳定,纤维形貌开始变的不规则,随着浓度的进一步增大,纤维形貌更不好以致很难成功纺丝;拉伸测试表明,NCP对PLA电纺纤维的强度有很大影响,随着磷酸钙浓度的增大,拉伸强度是不断增加的,但是,当浓度超过7%后,强度又逐渐变小。利用新型电纺法制备了排列取向复合纤维并且利用扫描电镜对其进行了表征。扫描电镜结果表明,所得的纤维具有较好的排列取向,而且纤维的直径较常规纺丝法得到纤维要大2～3倍。掺加的NCP浓度为0～7%时,纺丝状态较稳定;但是随着NCP浓度继续增加到9%～15%时,纺丝状态开始不稳定,出丝变得不连续;当NCP浓度达到15%时,几乎很难成纤。更多还原

【Abstract】 In this paper, electrospinning of PLA was studied systematically and the effective factors in the electrospinning were also demonstrated. The results indicated that when solvent is the mixture of DCM and DMF, a good solution system can be gained for electrospinning. DCM and DMF mixed with a volume ratio of 8:2 or 7:3 were all suitable solvent system. When the concentration of the PLA is fixed, the distance between spinneret and the receiver has an effect on diameter of the fibers. While the distance is less than 10cm, it is easy to form superfine fibers with the increasing of the voltage. Electrospinning for PLA can be carried out under the voltage between 9kV and 22kV. As the increasing of the voltage, the diameter of fibers decreased and electrospinning process became unsteady. The diameter of fibers was a key factor for the tensile properties of PLA electrospun fibers. With the increasing of concentration of PLA solution, the tensile strength of PLA fibers mats increased in the beginning and decreased gradually. The higher voltage in the electrospinning made the tensile strength of PLA fiber mats decreased. Tensile strength increased with the increasing of molecular weight of PLA.Based on the research of PLA, biomedical composite nanofibers were prepared with Nano-Calcium Phosphate (NCP) mixed into Poly lactic acid (PLA) by electrospinning and arranged oriented composite fibers were made by new electrospinning. A series of PLA solutions with weight concentration of 7% were produced and NCP with weight concentration 0, 1%, 3%, 5%, 7%, 9%, 11% and 13% were mixed into solutions and then electrospinning was carried out. The amount of NCP was the percentage of the weight of PLA. Transmission Electronic Microscope (TEM) indicated that NCP was mixed into PLA successfully. Scanning Electronic Microscope (SEM) showed that when the NCP concentration was less than 7%, the surface morphology of the fibers had no obvious changes. However, with increase of the NCP concentration, the electrospinning process became unsteady and the morphology of the fibers turned bad. As the NCP concentration had a deep increase, the morphology of the fibers became worse so that it was difficult to electro spin successfully. Tension tests indicated that NCP made a great effect on tensile strength of electrospun nanofibers. With the increase of NCP concentration, tensile strength increased ceaselessly and when the concentration exceeded 7% the strength decreased. The arranged oriented composite fibers were prepared by new electrospinning and characterized by SEM. The SEM images revealed that the fibers owed perfect orientation and their diameters were 2 or 3 times larger than those made by traditional electrospinning. When the NCP concentration was 0-7%, the electrospinning process was relatively steady. Nevertheless, when the NCP concentration increased to 9%-15%, the electrospinning became unsteady and fibers became discontinuous. It was very difficult to get fibers when the NCP concentration reached 15%.更多还原