Determination of polymer–polymer interaction parameters using inverse gas chromatography

A modified method is discussed that is based on Farooque and Deshpande's method to obtain polymer–polymer interaction parameters using inverse gas chromatography (IGC) data. In the Farooque and Deshpande method, the ratio of the difference of probe–polymer interaction parameters between two polymers and the probe volume [(χ₁₂ ? χ₁₃)/V₁] is used as the abscissa. In the modified method, the ratio [(?₂χ₁₂ + ?₃χ₁₃)/V₁] is used as the abscissa. Experimental data previously reported for a poly(?‐caprolactone)‐polyepichlorohydrin (PCL/PECH) blend and a poly(ethyl acrylate)‐poly(vinyl propionate) (PEA/PVPr) blend are analyzed. It is found that the slopes obtained by the new method had smaller deviations from the theoretical values than the Farooque and Deshpande method. The standard deviations of both slopes and intercepts obtained from the new method are also smaller. Using the new method, the polymer–polymer interaction parameters obtained from the intercept are negative numbers for the PCL/PECH system and very small positive numbers for PEA/PVPr. Explanations are given for the probe and concentration dependency of the polymer–polymer interaction parameters that are generally observed in IGC studies. A new method for selecting the best probe for calculating the interaction parameter is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 671–680, 2003     

Towards General Guidelines for Aligned,Nanoscale Assemblies of Hairy‐Rod Polyfluorene

This account highlights recent progress towards understanding the complex hierarchical levels of solid‐state structure in a prototypical helical hairy‐rod polyfluorene, poly[9,9‐bis(2‐ethylhexyl)fluorene‐2,7‐diyl] (or PF2/6). This branched‐side‐chain containing polyfluorene undergoes a systematic intermolecular self‐assembly and liquid‐crystalline phase behavior in combination with uniaxial and biaxial alignment. The latter processes yield full three‐dimensional orientation of the crystallites and polymer chains. Also reviewed are the impact of the molecular structure and phase behavior on surface morphology, anisotropic film formation, and, ultimately, the overall impact of these physical attributes on optical constants. This particular polyfluorene also represents a model system for demonstrating the applicability of mean‐field theory in detailing the self‐organization of aligned hairy‐rod block‐copolymer systems. These results of PF2/6 are compared to those of other archetypical π‐conjugated hairy‐rod polymers. General guidelines of how molecular weight influences nanostructure, phase behavior, alignment, and surface morphology are given.     

Improvement of emission efficiency in polymer light-emitting devices based on phosphorescent polymers

We report improvement of emission efficiency in polymer light-emitting devices (PLEDs) employing phosphorescent polymers. A hole-blocking layer was inserted between the emissive layer and the cathode to enhance recombination efficiency for the injected holes and electrons. Aluminum(III)bis(2-methyl-8-quinolinato)4-phenylphenolato (BAlq) was used for the hole-blocking layer. The resultant PLEDs exhibited significant improvement of emission efficiency. The respective external quantum efficiencies for red, green and blue PLEDs were 6.6, 11 and 6.9%. These values are very high compared with those based on conventional fluorescent polymers.     

XPS studies of directly fluorinated HDPE: problems and solutions

X-ray photoelectron spectroscopy (XPS) applied to the study of fluorinated polymer surfaces presents several problems related both to peak assignment and to degradation. In this work, we analyse extensively the question of XPS peak assignments in this kind of surfaces. We conclude that in this kind of surfaces using binding energy differences between fluorine and carbon is better than using absolute binding energies. Also a useful relation between fluorine photoelectron energy vs. polymer composition expressed through the atomic ratio fluorine/carbon (F/C) was found. A protocol for data treatment is proposed and applied to a XPS study of the degradation induced by X-ray on high-density polyethylene surfaces modified by direct fluorination. Results obtained for the degradation, namely the atomic ratio F/C obtained by two different methods, combined with angle resolved X-ray photoelectron spectroscopy (ARXPS) were used to study the fluorine concentration profile in depth, producing self-consistent results.     

P／MCs新型复合材料制备、结构及阻尼性能

采用特殊的渗流法所制备的新型Ｐ／ＭＣｓ复合材料，由高分子聚合物与蜂窝状铝架组成，它具有优异的阻尼性能，并简述了结构对阻尼的影响     

高聚物共混物及嵌段共聚物熔体的流变性（Ⅰ）共混物熔体的流动特性

综述了高聚物二元共混物及嵌段共聚物熔体的静态流变性，分析了不同共混体系的流动曲线，总结了共混物的流动特性及规律     

非反应性共聚物增容剂的作用

简述了共聚物增容剂在聚合物熔融共混物中的作用方面的研究进展。阐述了A-B、A-C和D-E型非反应性共聚物增容剂。重点介绍了增容剂的分子量、用量对聚合物共混物的界面张力、相畴尺寸和聚结的影响。     

电子型／离子型导电高分子共混物

用苯胺在酸性水溶液中的进行化学氧化聚合合成了能溶于Ｎ－甲基吡咯烷酮的高分子量聚苯胺（ＰＡｎ），并用这种ＰＡｎ与一种高分子固态离子导体－－聚乙二醇聚醚氨酯脲（ＰＥＵＵ）和ＬｉＣｌＯ４的复合物（ＰＥＵＵ－ＬｉＣｌＯ４）进行溶液共混制得了具有电子型／离子型两种导电功能的新型高分子共混物。用差示扫描量热法、动态粘弹仪、应力－应变试验、四探针法和交流阻抗谱对这种高分子共混物进行研究。实验结果表明，上述ＰＡｎ     

Magnetic properties of nickel filament polymer-matrix composites

The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam) were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m³ of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m³ and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m³ and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m³ and 2.3 kA/m for solid polycrystalline nickel.     

热致液晶性纤维素衍生物及其热塑性塑料复合物熔体流变行为的研究

用毛细管流变仪研究了乙基纤维素（ＥＣ）及其高密度聚乙烯（ＨＤＰＥ）复合物，纤维素芳族酯（ＣＡＥ）及其聚碳酸酯（ＰＣ）复合物的剪切流变特性和机理。结果表明，ＥＣ对ＨＤＰＥ／ＥＣ复合物的粘度影响不大，而少量（５％）ＣＡＥ的加入使ＰＣ／ＣＡＥ复合物粘度大大下降，且复合物流变曲线呈现新的特征。