【作者】 张青芳；

【导师】 谢青季； 刘平桂；

【作者基本信息】 湖南师范大学 ， 分析化学， 2009， 硕士

【摘要】 聚氨酯树脂具有粘附力强、柔韧性好等优异性能而成为越来越重要的工程材料,但它较差的耐温性能和耐化学腐蚀性能阻碍了其广泛应用。为进一步提高聚氨酯的性能,我们引入含酰亚胺基团、环氧树脂、有机硅改性环氧树脂与聚氨酯复合达到提高聚氨酯性能的目的。在二苯基甲烷-4,4’-异氰酸酯（MDI）与偏苯三甲酸酐（TMA）反应的基础上,以聚醚-MDI聚氨酯预聚体Suprasec^?9272、自制的聚四氢呋喃醚二元醇（PTHF）-MDI预聚体、聚碳酸酯二元醇（PCDL）-MDI预聚体与TMA反应,合成了数种端羧基聚（氨酯-酰亚胺）（PUI-Ⅰ、PUI-Ⅱ和PUI-Ⅲ）,并通过傅立叶红外（FT-IR）、核磁（NMR）和电喷雾离子质谱（EIS-MS）等方法对合成产物进行了结构表征。在PUI-Ⅰ中加入双酚A型环氧树脂（DGEBA）和酚醛环氧树脂（EPN）,在PUI-Ⅱ和PUI-Ⅲ中加入DGEBA和有机硅改性DGEBA,以多官能团氮丙啶（polyfunctional aziridine）为固化剂,制备了不同结构类型的聚氨酯/环氧树脂复合材料。分析了不同环氧树脂、不同二元醇低聚物和有机硅改性DGEBA等对复合材料热稳定性能、动态力学性能、拉伸性能、耐化学腐蚀性能等的影响。结果表明,环氧树脂的加入,PUI-Ⅰ体系的5%和10%失重温度(T_5%,T_10%)提高了约30℃;PUI-Ⅱ系列材料的性能优于PUI-Ⅲ系列材料;有机硅改性DGEBA的加入使PUI-Ⅱ第一阶段和第二阶段的最大分解温度都提高了15℃,断裂伸长率则由120%降到了50%左右,强度变化不大。用电化学石英晶体微天平研究了羟基磷灰石的电沉积过程。10mM Ca（NO₃）₂+6 mM NH₄H₂PO₄+20 mM对苯醌（BQ）溶液中BQ在-0.2 V下恒电位的电还原可沉积磷酸盐,经碱处理后得到致密的羟基磷灰石涂层。用石英晶体微天平（QCM）,FT-IR和小角X射线衍射（XRD）对其进行了表征。以羟基磷灰石为基底,制备了一种新型葡萄糖酶电极。结果表明,在最佳实验条件下,该传感器的线性范围为0.058-1.7 mM,检测下限为0.34μM,灵敏度为32.2μA mol^-1 cm^-2,抗干扰能力强,稳定性好。测得米氏常数(Michaelis-Menten constant,K_m^app)为5.2 mM。更多还原

【Abstract】 Polyurethanes（PU） are becoming more and more important as a kind of engineering materials due to their many excellent properties,such as good plasticity and high flexibility.However,poor chemical resistance and thermal stability limit PU’s wider applications in many fields.Here, imide,epoxy and silicon-modified epoxy are introduced to improve the thermal and mechanical properties of polyurethanes.Based on the model reaction between 4,4’-diphenylmethane diisocyanate （MDI） and trimellitic anhydride（TMA）,carboxyl-terminated poly（urethane-imide）s（PUI-Ⅰ,PUI-Ⅱand PUI-Ⅲ） are synthesized from the reaction between TMA and different isocyanate terminated polyurethane prepolymers,such as Rubinate^? 9272（a polyether-MDI prepolymer）, self-prepared polytetrahydrofuran diol（PTHF）-MDI and polycarbonate diol（PCDL）-MDI prepolymer.All resultants are characterized by Fourier transform infrared spectroscopy（FT-IR）,nuclear magnetic resonance （NMR） and electrospray ionization mass spectrometry（EIS-MS）.After blending PUI-Ⅰwith epoxy resin（diglycidyl ether of bisphenol A,DGEBA） or novolac epoxy resin（EPN）,PUI-Ⅱor PUI-Ⅲwith DGEBA and the triethoxysilane-modified DGEBA,different epoxy resin modified PU composites are prepared,which are cured with a polyfunc- tional aziridine CX-100 at a low temperature.The effects of the type of epoxy resin and oligomer polyols of PUI,and the molar ratio of triethox-ysilane -modified epoxy resin to epoxy resin are studied on morphological, thermal,mechanical properties and chemical resistance of these composites. It is experimentally shown that introducing epoxy resin into PUI-Ⅰresults in increases of the degradation temperature at 5%and 10%weight loss(T_5%,T_10%) by 30℃.And also,the properties of modified PUI-Ⅱseries composites are superior to those of modified PUI-Ⅲseries.For modified PUI-Ⅱseries,the maximum decomposition temperatures at 1^st-and 2^nd-step degradation are increased by 15℃,due to an increased crosslinking density and the reinforced effects from introducing silicon -modified epoxy resin,however,the elongation at break was decreased from 120%to about 50%,and the tensile strength changed a little.The electrochemical quartz crystal microbalance（EQCM） was used to quantitatively examine the electrodeposition of hydroxyapatite（HA） at a gold electrode.Potentiostatic electroreduction of p-benzoquinone（BQ） in 10 mM Ca（NO₃）₂+6 mM NH₄H₂PO₄+20 mM BQ at potentials negative to -0.2 V vs the KCl-saturated calomel electrode（SCE）,and thus a calcium phosphate（CP） film was precipitated on the electrode.A further NaOH treatment of the CP deposit led to a uniformly distributed HA coating on the electrode,as proven by quartz crystal microbalance （QCM）,Fourier transform infrared（FT-IR） spectroscopy and X-ray diffraction （XRD）.At an optimal experiment condition,the resultant sensor exhibited high sensitivity(32.2 mA mol^-1 L cm^-2) with a linear response range of 0.058～1.7 mM for glucose,fast response（response time was about 5 s）,low detection limit（0.34μM） and good storage stability.The apparent Michaelis-Menten constant of the immobilized GOD was calculated to be 5.2 mM.更多还原