聚四氟乙烯纤维的辐照接枝改性及其应用

【作者】 韩晓燕；

【导师】 张政朴；

【作者基本信息】 南开大学 ， 高分子化学与物理， 2009， 博士

【摘要】 本文采用惰性的聚四氟乙烯（PTFE）纤维为骨架,以甲基丙烯酸缩水甘油酯（GMA）为单体,共辐照法制备接枝纤维（PTFE-GMA）,接着采用聚乙烯亚胺（PEI）作为胺化试剂,与GMA发生开环胺化反应制得新型的PTFE-GMA-PEI纤维。研究了PTFE-GMA-PEI纤维对溶液中胆红素及重金属离子吸附性能,并进一步将PTFE-GMA-PEI纤维填充微柱与ICP-OES联用在线检测中成药样品痕量Pb、Cd含量及环境水样中Cr（Ⅲ）和Cr（Ⅵ）形态。具体内容如下:首先以PTFE纤维为基质,以GMA作为单体,采用共辐照法,在辐照剂量20 KGy,阻聚剂浓度为2.5%,交联剂与单体比例为1:4,单体质量浓度为20%的接枝条件下制备得接枝率97%的PTFE-g-GMA纤维,盐酸吡啶法测定PTFE-g-GMA纤维中环氧基含量为2.2 mmol·g^-1,接着通过聚乙烯亚胺与纤维表面GMA的开环胺化反应得到PTFE-g-GMA-PEI纤维,酸碱滴定法测定PTFE-g-GMA-PEI纤维中氨基含量1.87 mmol·g^-1。其次通过一系列吸附实验考察了PTFE-g-GMA-PEI纤维对胆红素的吸附效果。考察了吸附体系的pH值、离子强度、温度及牛血清白蛋白（BSA）存在对胆红素吸附的影响。结果表明该吸附剂具有较高的吸附容量及优异的吸附性能。该吸附剂对于血液灌流生物医学体外解毒过程的应用前景广阔。先通过采用静态与动态两种吸附方法,研究了PTFE-g-GMA-PEI螫合纤维对Cu²⁺,Cd²⁺、pb²⁺等三种重金属离子的吸附性能与解吸性能,考察了各种因素对螯合吸附纤维吸附性能的影响。研究结果表明,螯合吸附纤维对Cu2²⁺,Cd2²⁺、pb2²⁺等三种重金属离子具有很强的螯合吸附作用,螫合吸附属于单分子层的化学吸附,吸附行为符合Langmiur吸附;溶液的pH、吸附温度对吸附容量影响较大;温度越高吸附容量越大,说明螯合吸附过程为吸热过程。此外,PTFE-g-GMA-PEI螯合纤维具有良好的解吸性能。接着采用自制固相萃取材料PTFE-g-GMA-PEI纤维填充微柱预富集和流动注射（FI）与电感耦合等离子发射光谱仪（ICP-OES）联用测定样品中痕量铅、镉。对铅、镉离子的富集与洗脱条件进行优化,并给出相应离子的分析特性。该方法应用于几种中成药中的痕量铅、镉的同时测定。最后考察了Cr（Ⅲ）和Cr（Ⅵ）在PTFE-g-GMA-PEI纤维上的吸附性能,在pH值为7.0时,PTFE-g-GMA-PEI纤维对Cr（Ⅲ）和Cr（Ⅵ）的吸附性能有很大差异,据此建立了一种分离测定不同形态的铬的新方法,并已成功用于环境水样中铬的形态分析,其精密度与准确度比较满意。更多还原

【Abstract】 The novel adsorbent of PTFE-g-GMA-PEI fiber based on PTFE fiber was prepared by ⁶⁰Co radiation-induced graft polymerization with GMA and by subsequent chemical modification of the epoxy group of PTFE-g-GMA fiber with PEL The aim of this dissertation is to study systematically the adsorption characteristics of the bilirubin and some metal ions on the PTFE-g-GMA-PEI fiber, and apply it to the separation/preconcentration and speciationa analysis of trace heavy metal elements. The major contents are described as follows:The effect of pH, ionic strength, temperature, BSA, initial bilirubin concentration and adsorption dynamics on the adsorption capacity of PTFE-g-GMA-PEI fiber for bilirubin was investigated in a batch system. The maximum adsorption capacity of the grafted fiber was 9.6 mg g^-1 at pH = 6.5. The bilirubin adsorption on this fiber obeyed the Langmuir model. Besides, this fiber possessed the ability to selectively adsorb bilirubin in the co-presence of BSA.Comparison with other bilirubin sorbents showed that the PTFE-g-GMA-PEI fiber had good adsorption capacity and high selective adsorption for bilirubin. The new adsorbent had the advantage of fiber material. In addition, this adsorbent was inexpensive , easy to prepare and had no toxicity. So the PTFE-g-GMA-PEI fiber as the biomedical adsorbent was promising for removing bilirubin through hemoperfusion technique.The chelating adsorption characteristics of some metal ions （Cu, Pb, Cd） on PTFE-g-GMA-PEI Fiber under the static and dynamic condition were studied, and the adsorption conditions were optimized. The PTFE-g-GMA-PEI fiber possesses very strong chelating adsorption ability for heavy-metal ions, and the saturated adsorption capacity can reach 28.3 mg·g^-1,32.4 mg·g^-1 and 5.8 mg·g^-1 for Cu²⁺ , Cd²⁺ and Pb²⁺ under dynamic conditions, respectively. The isothermal adsorption data fit to Langmuir equation, and the adsorption is typical chemical adsorption with monomolecular layer. The adsorbing ability of the PTFE-g-GMA-PEI fiber towards the three kinds of the ions follows the order of Cd²⁺ > Cu²⁺ > Pb²⁺. The pH value has great influence on the sorption. The fact that adsorption capacity increases with temperature rising indicates the adsorbing process of the PTFE-g-GMA-PEI fiber for metal ions is endothermic. As diluted nitric acid is used as eluent, the adsorbed heavy-metal ions are eluted easily from the PTFE-g-GMA-PEI fiber.Using a micro-column packed with PTFE-g-GMA-PEI Fiber made by ourselves as the adsorption material, the adsorption behaviors of Pb and Cd on the above material under different conditions were studied by inductively coupled plasma optical emission Spectrometry ICP-OES). The conditions for the preconcentration of Pb and Cd such as pH, flow-rate, timer eluention agent and its acidity were optimized. A new method of PTFE-g-GMA-PEI Fiber as the adsorbent separation/ preconcentration coupled with ICP-OES for simultaneous determination of Pb and Cd in traditional Chinese Medicine was proposed.At last, a PTFE microcolumn packed with PTFE-g-GMA-PEI Fiber was used in a Fl-ICP-OES system for the speciation of Chromium.Based on the difference of adsorption behavior of Cr（III） and Cr（VI） on the PTFE-g-GMA-PEI Fiber, a simple and convenient method was developed for the speciation of chromium by selective adsorption of Cr（III） and Cr（VI） on PTFE-g-GMA-PEI Fiber at different pH.The proposed method was applied to the analysis of real water samples.更多还原