利用Heck反应制备立构规整聚(3-己基噻吩)

采用Heck反应法合成了具有较高分子量和立构规整度的聚(3-己基噻吩)。研究了溶剂的种类及配比、相转移催化剂及催化剂的种类以及反应温度、反应时间对所得聚(3-己基噻吩)的分子量和规整度的影响。用凝胶色谱(GPC)和核磁共振谱(1HNMR)对聚(3-己基噻吩)的分子量及立构规整度进行了表征。用紫外-可见分光光度计和荧光分光光度计研究了聚(3-己基噻吩)的吸收光谱和发射光谱。结果表明,当溶剂为二甲基甲酰胺与四氢呋喃(DMF:THF=1:1)的混合溶剂,采用醋酸钯[用量为单体量的5%(摩尔分数)]为催化剂,四丁基溴化铵[用量为单体量的100%(摩尔分数)]为相转移催化剂时,在80℃下反应12h所得聚(3-己基噻吩)的分子量可达6700,立构规整度超过96%。     

高等规聚3-己基噻吩的合成与研究

基于GRIM法合成了高等规的聚3-己基噻吩(rr-P3HT),研究了反应中催化剂和格氏试剂用量、反应温度和时间对产物产率的影响。采用GPC、1H-NMR和TGA法对其结构进行表征,结果显示该聚合物具有高度的规整性和良好的热稳定性。通过紫外吸收光谱、荧光发射光谱表征了聚合物的光物理性能,其最大紫外吸收峰和相应的发射峰分别位于455nm和573nm。     

基于聚3-己基噻吩的嵌段共聚物研究进展

随着全球对新能源、新材料研究领域的战略提升,聚3-己基噻吩(P3HT)作为导电共轭聚合物的相关研究已成为近年来的一个热点,并取得了突飞猛进的进展。P3HT均聚物受其激发子寿命短的影响,其光电转换效率有限,而嵌段共聚物可以实现微相分离,进而可以实现提高有机光伏材料的光电转换效率的目的。总结了近年研究者们合成的嵌段共聚物及其合成方法。     

3-己基噻吩与3-乙羧基噻吩电化学共聚与性能研究

研究了 3 己基噻吩单体及 3 己基噻吩与 3 乙羧基噻吩电化学共聚合成的合成原理、合成条件及方法。对 3 己基噻吩与 3 乙羧基噻吩电化学共聚物的电导率、导电稳定性、溶解度、相对分子质量及红外光谱特性进行了测试和分析。结果表明 ,共聚物较单体分子量增大 ,性能得到明显改善 ,特别是导电稳定性和机械性能改善较大     

聚（3-己基噻吩）-聚苯乙烯嵌段共聚物的一锅法制备

采用具有聚苯乙烯高分子链为配位基团的聚合催化剂,催化2,5-二溴-3-己基噻吩单体进行Kumada缩聚反应,利用一锅法制备了聚（3-己基噻吩）-聚苯乙烯嵌段共聚物。结果表明：采用一锅法,在室温、常压条件下进行一步聚合直接生成嵌段共聚物,反应过程简单,聚（3-己基噻吩）与聚苯乙烯嵌段对接率接近100%;与聚（3-己基噻吩）相比,聚（3-己基噻吩）-聚苯乙烯嵌段共聚物的结晶性能更好。     

“聚(3-己基噻吩)性质表征”应用于聚合物现代仪器分析实验教学的探讨

聚(3-己基噻吩)(P3HT)是一种重要的导电聚合物,其化学结构、光物理性质、相对分子质量、结晶性、热稳定性及表面形貌等测试表征涉及的仪器非常广泛。文章分析了以“聚(3-己基噻吩)性质表征”作为聚合物现代仪器分析实验课程基本实验的可行性及优势。认为该综合实验贯穿于聚合物现代仪器分析的实验教学,可使实验分为四个方面相关的内容,“波谱分析法”、“凝胶渗透色谱法”“热分析法”“电子显微镜”等有机结合,不仅能帮助学生掌握各种相关仪器的使用原理及分析方法,又能使他们直观清晰地了解各种方法的关联性及独立性,并且在教学过程中结合了科研实际需求,将理论知识与实践紧密结合起来。     

原位聚合制备尼龙-6/多壁碳纳米管复合材料及其结晶行为

采用酰氯化处理的多壁碳纳米管(MWNT)同氨基封端的尼龙-6(PA6)原位聚合的方法制备了PA6/MWNT复合材料.红外光谱说明了MWNT与PA6化学的键合作用.DSC测试表明MWNT对PA6的分子链段运动有较大的阻碍作用.动力学分析表明MWNT具有成核作用,提高了PA6的结晶温度;共价键连接使MWNT对PA6的分子链段运动有强烈的阻碍作用,造成复合材料(含MWNT质量分数2%)的总结晶速率降低.     

Structure and conductivity of multi-walled carbon nanotube/poly(3-hexylthiophene) composite films

This work reports a structure-property investigation of a conjugated polymer nanocomposite with enhanced conductivity. Regioregular poly(3-hexylthiophene) (rrP3HT) was used to prepare composites with thin, short, multi-walled carbon nanotube (MWNT) addition over a wide range of concentrations. Scanning and transmission electron microscopies demonstrated an excellent dispersion and good wetting properties within the carbon nanotube composites. Coated MWNTs showed superstructures of P3HT self-organized on nanotube surfaces. Changes in the long range order and on the self-ordered mesophase of the bulk material were investigated by infrared and Raman spectroscopies, differential scanning calorimetry and X-ray diffraction. Interplay between charge transport through the semiconducting polymer and carbon nanotube network increased the composite's conductivity after percolation to values close to 10⁻² S cm⁻¹.     

Electrochemical behavior of poly(3-hexylthiophene). Controlling factors of electric current in electrochemical oxidation of poly(3-hexylthiophene)s in a solution

Electrochemical response of regio-random and regio-controlled poly(3-hexylthiophene), P3HexTh, was investigated by cyclic voltammetry. P3HexTh underwent electrochemical oxidation at about 0.4 V vs. Ag⁺/Ag in a THF solution, and the peak anode electric current, i_pa, was proportional to the sweeping rate v; i_pa=const×v^1/2. These data indicated that diffusion of the P3HexTh molecule in the solution was important to determine i_pa. Application of a Matsuda's equation with assumptions gave a diffusion coefficient, D, of about 1×10⁻⁷ cm² s⁻¹ at molecular weight of about 5000, and the D value steeply decreased with increase in the molecular weight.     

Effect of surface-modified zinc oxide nanowires on solution crystallization kinetics of poly(3-hexylthiophene)

Interfacial interactions between donor and acceptor molecules are determinative to the device performance of hybrid photovoltaics. However, the dynamic process of such interactions remains largely obscure. In this work, we report the kinetic behavior of solution crystallization of poly(3-hexylthiophene) (P3HT) in anisole in the presence of ZnO nanowires by means of ultraviolet-visible absorption spectroscopy. ZnO nanowires are surface-modified by covalently attaching aliphatic and aromatic ligands to enhance the miscibility and interfacial interactions between P3HT and ZnO nanowires. Upon cooling the hot solution to room temperature, a significant time-dependent chromism occurs spontaneously. Analysis of the kinetics of isothermal solution crystallization across a range of crystallization temperature displays that the growth rate of the crystals scales with polymer concentration as R ∝ C^1.6 for both the control P3HT and P3HT with ZnO nanowires. The Lauritzen–Hoffman theory of secondary nucleation is utilized to analyze the kinetic behavior of crystallization, and the fold surface free energies of the crystals of P3HT in anisole are calculated to be 6.6–10.3 × 10⁻² J m⁻². It is found that the addition of surface-modified ZnO nanowires decreases the fold surface free energy by 21.5% and 43.8%, respectively, for aliphatic and aromatic ligands.     

Preparation and electrical conductivity of Langmuir–Blodgett films of poly(3-alkylthiophene)s

Five poly(3-alkylthiophene)s (P3ATs) with different alkyl side chains were synthesized. Pure P3ATs alone are not well suited for manipulation by the Langmuir–Blodgett (LB) technique, but their mixed systems with arachidic acid can be used to prepare high-quality Y-type films with the vertical dipping method, which was proved by UV-visible spectra and small-angle X-ray diffraction patterns. Conductivities of the LB films were measured using a two-probe method at room temperature. The conductivities exhibited obvious anisotropy and could increase by 2–4 orders of magnitude after iodine vapor doping. The influence of alkyl chain length on the conductivity in the LB films was revealed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1–6, 1998     

Preparation and properties of poly(ethylene terephthalate)/ATO nanocomposites

Antimony doped tin oxide (ATO) nanoparticles modified poly(ethylene terephthalate) (PET) composites used for manufacturing antistatic PET fiber were synthesized by in situ polymerization. The crystallization and multiple melting behavior of the nanocomposites were systemically investigated by means of Differential Scanning Calorimeter (DSC), Fourier Transform Infrared (FTIR), X‐ray Diffraction (XRD) techniques. The degree of crystallinity in nanocomposites increased with increasing ATO content. Smaller and more incomplete crystals are presented in the crystalline regions of the nanocomposites with increasing the content of ATO, which could be attributed to heterogeneous nucleation effects of ATO nanoparticles. Dynamic Mechanical Analysis (DMA) measurements showed that the storage moduli of the nanocomposites increased with increasing the content of ATO, due to formation of immobilized layer between polymer and filler. The interactions between ATO and PET molecules result in high tan δ for the PET/ATO nanocomposites. Percolation threshold of PET/ATO hybrid fibers prepared by the nanocomposites at room temperature was as low as 1.05 wt %, much lower than that of the composites filled with conventional conductive particles. Adding ATO nanoparticles obviously improves the conductivity of PET. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Orientation microstructure and properties of poly(propylene carbonate)/poly(butylene succinate) blend films

The blends of high molecular weight poly(propylene carbonate) (PPC) and poly(butylene succinate) (PBS) were melt blended using triphenylmethane triisocyanate (TTI) as a reactive coupling agent. TTI also serves as a compatibilizer for the blends of PPC and PBS. The blend containing 0.36 wt % TTI showed that the optimal mechanical properties were, therefore, calendared into films with different degrees of orientation. The calendering condition, degree of orientation, morphologies, mechanical properties, crystallization, and thermal behaviors of the films were investigated using wide‐angle X‐ray diffraction, scanning electron microscopy, tensile testing, and differential scanning calorimetry (DSC) techniques. The result showed that the as‐made films exhibited obvious orientation in machine direction (MD). Both tensile strength in MD and the tear strength in transverse direction (TD) increased with increasing the degree of orientation. The orientation of the film also increased the crystallinity and improved the thermal properties of the PPC/PBS blend films. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Morphology and electrical properties of carbon black-filled poly(ε-caprolactone)/poly(vinyl butyral) blends

Electrical properties of poly(ε-caprolactone) (PCL)/poly(vinyl butyral) (PVB) blends containing carbon black (CB) were studied as a function of a small amount of PVB content and a wide range of molecular weight of PVB. For samples with the same CB content, the intensity of positive temperature coefficient (I_PTC, defined as the ratio of peak resistivity to resistivity at room temperature) of the blends was increased, with PVB content greatly and molecular weight of PVB weakly. As the band spacings of PCL spherulites in PCL/PVB blends decrease with PVB content and molecular weight of PVB, the changes of the positive temperature coefficient property are ascribed to the morphological difference (i.e., period of twisted lamellae) in the blends. We confirmed our previous conclusion that the origin of the positive temperature coefficient phenomenon is the changes of the distribution of the CB on the melting of the crystalline phase. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 193–199, 1998     

Electrical conductivity of poly(vinyl alcohol)/carbon nanotube multilayer thin films: Influence of sodium polystyrene sulfonate mediated carbon nanotube dispersion

This investigation was aimed to enhance the dispersibility of multi-walled carbon nanotubes (MWCNT) using sodium polystyrene sulfonate (Na-PSS) polyelectrolyte. Subsequently, electrically conducting, multi-layer thin films are prepared utilizing layer by layer assembly method with poly(vinyl alcohol) as a host matrix. The highest extent of MWCNT dispersion was observed in MWCNT:Na-PSS ratio of 1:9 (wt/wt), which was estimated from UV-Vis spectroscopic analysis. Zeta potential measurements of Na-PSS modified MWCNT dispersion showed large negative potentials ranging from −52 to −64 mV in the most stable pH range of 4 to 10, suggesting the colloidal stability is due to the long-range repulsive nature of electrostatic interactions from negatively charged sulfonate groups. Complementary molecular dynamics simulations showed that adsorption of Na-PSS imparts a large negative potential to the carbon nanotube surface, which increases with an increase in Na-PSS concentration. The multi-layer thin film of (1:9) MWCNT:Na-PSS exhibited a DC electrical conductivity of 2.96 × 10² S/m.     

聚苯胺/氧化石墨烯接枝复合材料的制备及电容性能研究

利用化学氧化法原位聚合制备了聚苯胺(PANI)/氧化石墨烯(GO)接枝复合材料。透射电子显微镜表明,PANI纳米颗粒均匀地分布在GO的表面;通过UV-vis光谱证实了GO和PANI之间存在着强烈的相互作用;充放电测试表明,PANI/GO纳米复合材料具有良好的电荷储存特性,最高比电容可达575 F/g。由于与GO之间的化学结合作用,PANI的充放电循环稳定性得到明显提高。