【作者】 沈玉萍；

【导师】 孙建中；

【作者基本信息】 浙江大学 ， 化学工程， 2005， 硕士

【摘要】 本文研究了辣根过氧化物酶(HRP)催化水溶性导电聚苯胺的模板导向聚合。选用聚乙烯磺酸钠(PVS)作为苯胺聚合的新模板,仔细考察了反应条件对聚合产物的影响并与其他模板聚合产物进行了比较。在此基础上,对固定化辣根过氧化物酶酶促苯胺聚合进行了探索性研究。在游离态酶酶促聚合水溶性导电聚苯胺的研究中,考察了反应体系的pH值、H2O2浓度及苯胺单体与模板的摩尔比对聚合的影响,用UV-vis-near-IR、FTIR、TGA及四探针电导率测试仪对产物进行了表征。研究结果表明,PVS可以作为HRP酶催化苯胺聚合的模板。反应在室温(25℃)下进行,反应体系的pH值应该控制在4. 0-5. 0之间,作为引发剂的H2O2浓度在10mM-20mM之间为宜,PVS(单体单元)与苯胺的摩尔比应控制在1-1. 5之间。PANI/PVS的电导率为4. 78×10-1S/cm,明显高于已见报道的其他模板聚合物。在固定化酶酶促聚合导电聚苯胺的研究中,考察了通过共价交联法将酶分别固定在壳聚糖粉末表面和海藻酸钙(CA)凝胶微球表面实现酶的固定化、以及通过海藻酸钠-壳聚糖-海藻酸钠(ACA)微胶囊固定酶。实验结果表明,通过共价交联法得到的固定化酶可以成功用于催化苯胺聚合,而微胶囊固定化酶用于聚合则不成功。固定在壳聚糖表面的HRP酶保持了稳定性,室温下在pH6. 0的缓冲液中储存72小时仍然具有活性,用于催化聚合PANI/PVS时,反应体系的最适pH值、引发剂H2O2的最佳浓度均与使用游离酶时相同,固定化酶的最佳用量在0. 1g/mL附近。海藻酸钙凝胶微球表面固定HRP酶即得到功能微球,较壳聚糖粉末便于过滤回收,减少酶的损失。功能微球是一种很有研究前途的酶固定法,还有待深入探索。本文的研究工作为以后进一步研究酶催化苯胺聚合提供了必要的实验和理论基础。更多还原

【Abstract】 Enzymatic synthesis of a water-soluble, conducting polyanline (PANI) using a template-guided approach was studied in this paper. Horseradish peroxidase (HRP) is used to polymerize aniline in the presence of a new polyanionic template, poly(vinylsulfonic acid, sodium salt) (PVS). The effects of reaction conditions on the polymerization were worked out. Meanwhile, the products were compared with those synthesized using different templates. And what is more, the method for the synthesis of polyaniline with the immobilized horseradish peroxidase enzyme was investigated.In the study of polymerization of aniline catalyzed by free HRP, effects of different buffer solution, concentration of initiator (H2O2), and the molar ratio of aniline to PVS (based on the monomer repeat unit) on the polymerization were investigated. The products were characterized by UV-vis-near-IR and FTIR spectroscopy, thermogravimetric analysis, and four-point probe conductivity measurement. The results showed that PVS could be used as a new template in the synthesis of PANI. The reaction should be carried out in a 4.0~5.0 pH buffer aqueous solution at room temperature (25 °C). The concentration of initiator (H2O2) was 10nM~20nM, and the molar ratio of PVS to aniline was 1-1.5. The conductivity of PVS/PANI complex was 4.78 X10’1 S/cm, which was obviously higher than any other complex already having been reported.In the study of polymerization of aniline catalyzed by immobilized HRP, the enzyme HRP was immobilized on chitonsan powder and the surface of calcium alginate (CA) microspheres respectively by a simple glutaraldehyde bridge method. The alginate-chitosan-alginate (ACA) microcapsules were also used to immobilize HRP. The results showed that the HRP immobilized on chitosan powder and CA microspheres was an effective catalyst for the polymerization of aniline. It was defeated while using the HRP immobilized by ACA microcapsules as catalyst. The HRP immobilized on chitosan powder was stable and remained active after being stored in pH6.0 buffer solution at room temperature for about 72hr. When the immobilized HRP was used in the reaction, the proper pH of buffer solution and concentration of initiator (H2O2) were similar to that ofpolyaniline obtained with free HRP. The amount of catalyst used should be controlled around 0.lg/mL. The microspheres with HRP immobilized on the surface were functional microspheres, which were easier to recover than the chitosan powder. Functional microspheres are remarkable and need to be further investigated.This paper provides necessary experimental and theoretical foundation for further studies of enzyme-catalyzed polymerization of aniline.更多还原