The effect of heat treatment on the structure and morphology of poly （p-phenylene benzobisoxazole） fiber

The effect of heat treatment on the structure of Poly（p-phenylene benzobisoxazole） （PBO） fiber was studied by wide angle X-ray diffraction （WAXD） and differential scanning calorimetry-（DSC）, which resuits in confirmation of secondary crystallization in the heat treatment process. The effect of heat treatment on the structure and morphology of PBO fiber＇ s surface was investigated with X-ray photoelectron spectroscopic analysis （XPS）, scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The results show that heat treatment not only has an effect on the composition of PBO fiber＇s surface, but also improves the microstmcture of PBO fiber, makes fiber more regular.     

Raman spectroscopic studies on the structural changes of poly(3-methylthiophene) during heating and cooling processes

Poly(3-methylthiophene) (PMeT) electrosynthesized by direct oxidation of 3-methylthiophene in boron trifluoride diethyl etherate (BFEE) has been studied by Raman spectroscopy in the temperature scale of 123-458 K. Experimental results demonstrate that the thermal stability of PMeT in the oxidized state is much lower than that of the polymer in the neutral state. Furthermore, during the cooling process, the conformation of neutral species changes from a coil-like state into a rod-like state, while the conformation of the oxidized species does not change.     

粘度法研究SDS与PEO之间的相互作用

采用粘度法测定了不同温度下 ( 2 98 1 5K ,30 8 1 5K ,31 8 1 5K)阴离子表面活性剂十二烷基硫酸钠 (SDS)—水溶性聚合物聚氧乙烯 (PEO)体系在有无电解质 (NaOH)存在时溶液的宏观粘度 ,研究了SDS—PEO体系分子间相互作用对PEO构型的影响 ,得到了不同SDS—PEO体系的临界聚集浓度 (CAC)和聚合物饱和浓度 (PSP) ,并根据表面活性剂—聚合物体系相互作用模型计算了SDS胶束被吸附到聚合物PEO过程的吉布斯函数变 ,讨论了SDS—PEO体系分子间相互作用强度 结果表明 ,在所研究范围内 ,SDS—PEO体系有无电解质溶液的比浓粘度均随聚合物PEO浓度的减小而急剧升高 ,呈现典型的聚合电解质行为 ,而且SDS的浓度越大 ,电粘效应愈明显 由此可以推断 ,聚合物PEO与表面活性剂SDS之间主要是通过疏水键相互结合 ,PEO分子链处于更伸展的状态 NaOH的存在使聚合物PEO分子与胶束结合位置减少 ,聚集体的体积减小 ,或者介电常数增大 ,因此表现出电粘效应弱于不含碱的表面活性剂—聚合物体系 ,而且使其分子间相互作用强度降低     

荧光法研究苯甲酸氮芥铕配合物与DNA的相互作用

 在Tris-HCl(pH7.2)介质中,研究了1个新的苯甲酸氮芥铕(Ⅲ)配合物(Eu(BANM)₃·H₂O)与DNA相互作用的荧光性能,表明此配合物可作为DNA定量测定的荧光试剂.此外以溴化乙锭(EB)为荧光探针,对配合物与DNA的结合机理进行了探讨.结果证明DNA与配合物之间存在插入和沟结合2种非共价作用方式,配合物与DNA的平均结合常数为7.19×10⁵.