【作者】 隋坤艳；

【导师】 顾利霞；

【作者基本信息】 东华大学 ， 材料学， 2003， 博士

【摘要】 聚丙烯腈（PAN）纤维由于优良的性能，在工业和民用领域具有广泛的应用。但腈纶纤维的静电现象严重限制了腈纶在更多领域的应用。为此，腈纶的抗静电改性是一个重要的研究方向之一。 本论文采用铈离子／PEG氧化还原引发体系，在酸性水溶液中合成了聚丙烯腈-聚乙二醇的三嵌段共聚物（PAN-PEG-PAN）；首次研究了含有胺基的PEO（PEO-NH₂）与铈离子组成氧化还原引发体系，合成了聚丙烯腈-聚环氧乙烷的两嵌段共聚物（PAN-b-PEO）；FT-IR分析表明嵌段共聚物中PEO链的构象与均聚物PEO相比有很大的变化。研究还表明PEG引发剂浓度与分子量对聚合有较大的影响，随着PEG浓度的增加，聚合物的产率先呈增加趋势，而后逐渐下降；随着PEG分子量的增加，聚合物的产率下降，原因为缠结效应：研究还表明，Ce（Ⅳ）／PEO-NH₂引发体系存在诱导期，反应速率较Ce（Ⅳ）／PEG低。 应用广角X射线衍射、差示扫描量热（DSC）等方法，对嵌段共聚物的结晶性能及其热行为进行了研究。发现嵌段共聚物中，PAN嵌段和PEO嵌段的结晶形态都与均聚物相似，没有生成共晶。研究还表明，嵌段共聚物的组成对PAN和PEO嵌段的结晶特性有很大的影响。随着PEO组成的增加，嵌段共聚物的等温结晶样品的DSC曲线有不同的表现，PEO含量低时，PEO只有一个高温熔融峰；随着PEO含量的增加，DSC曲线上出现熔融双峰；进一步增加PEO的含量，PAN-b-PEG的DSC曲线只有一个低温熔融峰。高温峰的出现原因可能是PAN-b-PEG中PEG的不完善结晶的二次结晶，不同于均聚物PEG结晶的亚稳态。研究表明，PAN嵌段长度对PEO的熔点、PAN的玻璃化转变温度有很大的影响。在保持PEO嵌段长度不变的情况下，随着PAN嵌段长度的增加，PEO的熔点下降，PAN的Tg降低。首次研究了PAN-PEG-PAN、PAN-b-PEO中的PEO结晶行为的不同，研究表明，两嵌段共聚物中PEO链段的结晶能力较三嵌段共聚物中的PEG强。首次探讨了PAN-b-PEG中PEG的等速降温结晶性能，结果表明，PEG含量低时，PEG的结晶温度很低，过冷度很大，成核机理是均相成核；含量较高时，结晶温度较高，即过冷度较小时即可结晶，属于异相成核。 首次对嵌段共聚物PAN-b-PEG的DMF浓溶液的流变性能进行了详细的研究。结果表明，PAN-b-PEG的浓溶液为切力变稀流体。分析了不同温度下浓溶液的流变性能，首次发现PAN一b一PEG随温度的变化出现异常现象，在高温时，浓溶液的粘度反而升高，分析原因可能是PAN一b一PEG中PEG链段的二次结晶的熔融。PAN一b一PEG嵌段共聚物的粘流活化能随切变速率的增加而减小，并且随着嵌段共聚物中PEG含量的增加，PAN一b一PEG的粘流活化能上升，说明嵌段共聚物中PEG的加入导致共聚物原液对温度的敏感性增加。溶液的弹性模量和损耗模量都随剪切速率的增加而升高，随着温度的升高而降低。 对不同组成、不同结构的PAN一b一PEG嵌段共聚物的湿法纺丝进行了研究，结果表明随PEG含量的增加，PAN一b一PEG嵌段共聚物的可纺性变差;PEG的含量和结晶度对PAN一b一PEG嵌段共聚物纤维的吸湿性和抗静电性能有很大的影响，含量越高，结晶度越低，纤维的吸湿性、抗静电性能越好;同等含量情况下，三嵌段共聚物PAN一PEG一以N的抗静电性能较好:PAN一b--PEG嵌段共聚物纤维的力学性能随着PEG含量的增加有所下降，但可以满足服用性能的要求;以N一b一PEG嵌段共聚物纤维的抗静电性能具有永久性，经过洗涤后纤维的体积比电阻反而有所降低，共混纤维pAN/PAN一b一PEG的抗静电性能和耐洗涤性能都较差。 本论文首次采用四针状氧化锌晶须（Zn0W）为导电微粒，将其共混入聚丙烯睛纺丝原液中，制备了PAN/Znow抗静电纤维。研究结果表明，氧化锌晶须的尺寸及其分散状态对体系的抗静电性能、力学性能产生很大的影响;确定了采用粒径为5 pm的氧化锌晶须作为抗静电剂制备PAN/ Znow。研究了PAN/Zn伽纤维的体积比电阻与Znow含量之间的关系，发现它随Znow含量的增加逐渐下降并趋于稳定。分析了Zn伽抗静电纤维的导电机理，发现体系中除立体导电网络外，在外电场作用下，还存在晶须针尖电荷集中以及隧道效应。更多还原

【Abstract】 The purpose of this paper is to improve the antistatic property of polyacrylonitrile (PAN) fibers by using blend and copolymerization two methods.The triblock copolymer PAN-PEG-PAN was obtained by using Ce (IV)/PEG as redox initiation system in acidic aqueous. Meanwhile, the diblock copolymer PAN-b-PEO was first prepared by using PEO macromonomer containing amine end group (PEO-NH2) as the reduce agent in the same condition. The FT-IR measurement showed that the conformation of PEO in the block copolymer changes greatly. The effects of the concentration and the Mw of PEO on the polymerization are investigated. The results showed that the yield of product increased with the increasing of PEO concentration at first, and then decreased above the critical concentration due to the polymer chain’s entanglement. By comparison the difference between Ce(IV)/PEG and Ce (IV)/PEO-NH2 system, it was found that the polymerization rate of Ce (TV)/PEO-NH2 system was slower than the former.The thermal and crystalline properties of PAN-b-PEO block copolymers were studied by WAXD and DSC. The results showed that PEO content had great influence on the crystalline properties of PEO segments in the block copolymer. There was one PEO melting peak at high temperature in the DSC curves of isothermal crystallinized block copolymers with low content of PEO, and then two melting peaks were observed with increasing the PEO content, however, only one melting peak remained but at low temperature in the DSC curve of samples with higher content of PEO. The reason may be because of the fraction or second crystallization of imperfect PEO crystals in the PAN-b-PEO. This phenomenon has not been reported in the literature. The effect of PAN block length on the thermal properties of PEO and PAN was also study. It was found that the Tm of PEO and the Tg of PAN decreased as the increasing of PAN bloc length. The crystallinity difference of PEO segment in PAN-PEG-PAN and PAN-b-PEO two types block copolymer was first studied. The experimental results indicated that the crystallization of PEO segments would decrease in the following order:PAN-b-PEOPAN-PEG-PAN. The property of non-isothermal crystallization of PAN-b-PEG has been studied for the first time. The influence of PEO content on the crystallization mechanism was discussed. It was found for the first time that the crystallization mechanism of PEO segment in the block copolymer with low content of PEO is homogeneous nucleation. On the contrary, the mechanism is heterogeneous nucleation in higher content PEO of block copolymer.The rheological property of PAN-b-PEO concentrated solution was first studied carefully. The results showed that the solution was lower viscosity at higher shear rate and at higher temperature in the range of 40-60℃. But, a very strange phenomenon was found for the first time that the viscosity of PAN-b-PEG concentrated solution was higher at 70-80℃ than 60℃ especially at low shear rate. It may be due to the melting of secondary crystallization of PEG segments at such condition. Activation energy for PAN-b-PEG solution increased with the PEG content.The spinnability of PAN-b-PEG block copolymers were discussed and the hygroscopicity and antistatic property of PAN-b-PEG fiber and PAN/PAN-b-PEG blend fiber were also studied. It was found that the hygroscopicity and antistatic property were improved and the fiber had good mechanical properties. Furthermore, the volume resistivity of fiber becomes lower after washing. Therefore the PAN-b-PEG would be used widely for antistatic fibers.The tetrapod-shaped zinc oxide whisker (ZnOw) was first added to PAN spinning dope to improve its antistatic property. The results showed that the size and the dispersion of ZnOw had a great influence on the volume critical resistivity and mechanical properties. The electric resistivity of PAN/ZnOw fiber decreased as the increasing of ZnOw content in the composites. The analysis of the conductive mechanism indicated that the charge concentrating effect at the needles’ tip of the wh更多还原