Shape persistent hybrid dendrimers from benzene and triazole via ‘click chemistry’

Fully aromatic rigid dendrimers have been synthesized at room temperature based on two different ‘click’-reactions: The dendronization was carried out via the copper catalyzed azide–alkyne Huisgen cycloaddition or Diels–Alder cycloaddition, respectively. The feasible combination of both reactions leads to dendrimer hybrids. Stiff aromatic dendrimers, whose highly nitrogen containing scaffolds are solely based on interconnected benzene and triazole rings, were created.     

Novel fluorescent (p‐phenylene ethynylene)‐calix[4]arene‐based polymer: Design,synthesis, and properties

A novel fluorescent (p‐phenylene ethynylene)‐calix[4]arene‐based polymer ( CALIX‐PPE ) has been successfully synthesized by cross‐coupling polymerization of bis‐calix[4]arene 1 with 1,4‐diethynylbenzene. The polycondensation was carried out in toluene/NEt₃ at 35 °C for 24 h, using PdCl₂(PPh₃)₂/CuI as the catalytic system, furnishing CALIX‐PPE in excellent isolated yields (higher than 95%, several runs). The yellow polymer is freely soluble in several nonprotic organic solvents. The GPC trace of the isolated polymer showed a monomodal distribution and a number‐average molecular weight of 23,300 g mol^?1 (M_w/M_n = 2.05). No evidence was found in the structural analysis (FTIR and ¹H/¹³C NMR) regarding the formation of alkyne homocoupled segments along the polymer chain. For comparative purposes, the synthesis of an analogous poly(p‐phenylene ethynylene) containing p‐t‐butyl‐phenoxymethyl side chains ( TBP‐PPE ) was also undertaken. A great similarity was found between the photophysical properties of CALIX‐PPE and TBP‐PPE in solution (UV–vis and laser induced luminescence), clearly demonstrating their unique dependence on the structure and conformation of the conjugated PPE backbone. The fluorescence spectra of polymers are of nearly identical shape, displaying their maximum emission around 420 nm. The calculated solution photoluminescence quantum yields of CALIX‐PPE and TBP‐PPE are of similar magnitude (?_{F( CALIX‐PPE )} = 0.43; ?_{F( TBP‐PPE )} = 0.51). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6477–6488, 2008     

Synthesis and Characterization of Poly(meta-aryl sulfide amide amide)

Poly(meta-aryl sulfide amide amide) (m-PASAA) was prepared with aromatic nucleophilic substitution reaction: by the step polycondensation of sodium sulfide(Na₂S· xH₂O) with 3,3′ -bis(4-diflurobenzoyl) aryl diamine between 180–202°C at atmospheric pressure. The polymers were characterized by FT-IR spectrum, ¹H-NMR spectrum, ¹³C-NMR spectrum, X-ray diffraction, element analyzer, DSC, TGA, AFM, instron universal tester and dissolvability experiment. The intrinsic viscosity of m-PASAA was 0.41–0.46 dl/g obtained with optimum synthesis conditions. The polymers were found to have excellent thermal performance with glass transition temperature (T_g) of 233.5–277.8°C, initial degradation temperature (T_d) of 447–456.7°C. They could afford flexible and strong films with tensile strengths 38.4–46.1MPa. At the same time, their solubility was much better than polyphenylene sulfide (polyphenylene sulfide scarcely dissolves in whole organic solvents under 200°C (1 Yang, J. 2006. PAS resin and its application, China: Chemical Industry Press.  [Google Scholar])).     

强磁性聚合物的理论基础和展望

介绍了强磁性聚合物的理论基础和新的研究结果以及将来的应用。     

Synthesis, optical properties and crystal structures of carbazole end-capped phenylene ethynylene blue light-emitting materials

A class of highly fluorescent and stable carbazole end-capped phenylene ethynylene compounds have been synthesized and characterized. They show high extinction coefficients of absorption () and quantum yields of fluorescence (; Φ_F=0.52-0.73) in dichloromethane. The solid state absorptions and emissions are significantly red-shifted from the dilute solution ones (; ). Their photoluminescent properties and crystal structures have been investigated with the aim of providing a basis for elucidating the structure-physical property relationships. These data indicate their potential use as blue-emitting materials in organic light-emitting diodes (OLEDs).     

聚苯硫醚及其聚醚砜共混物结晶形态的研究

本文借用偏光显微镜(PLM)、扫描电子显微镜(SEM)、小角激光光散射仪(SALS)及蚀刻的方法,研完了聚苯硫醚及其与聚醚砜共混物的结晶形态和织构,讨论了共混方法及其共混组成对其共混物的结晶形态的影响。结果表明,聚苯硫醚在应力作用下能生成横晶;溶液共混物和粉末机械共混物呈现不同的共混结晶形态;随着聚醚砜组分的增加,共混物的织构从聚苯硫醚为连续相逐渐转变为聚醚砜为连续相,同时,聚醚砜的聚集区域从分散在聚苯硫醚的球晶之间转变为聚集在聚苯硫醚的球晶内,使聚苯硫醚的球晶形态逐渐变得不规整。     

聚苯醚合金的增容技术

介绍了增容剂的作用及其分类方法，详细综述了ＰＰＯ合金的各种增容技术，包括添加高分子和低分子增容剂，以及ＰＰＯ的官能化方法和由它而实现的原位增容，同时给出了各种增容剂的增容机理。     

支化反应型高分子量聚苯硫醚合成研究

本文以硫磺和对二氯苯为原料，在极性有机溶剂中合成聚苯硫醚（ＰＰＳ），加入含活性基团的二卤代苯作为共聚第三单体。研究表明，２，５－二氯硝基苯是一种较好的扩链剂，－ＮＯ２在反应中将被还原为－ＮＨ２，且－ＮＨ２在高温下与芳环进一步发生支化反应。当２，５－三氯硝基苯含量低于２％时，控制反应条件，能制得性能优良的支化反应型高分子量ＰＰＳ树脂。由于共聚第三单体量少，共聚物与中等分子量ＰＰＳ树脂具有相近的结构。     

聚苯硫醚及其聚醚砜共混物结晶动力学的研究

本文采用DSC方法,研究了聚苯硫醚及其聚醚砜共混物的等温结晶动力学。结果表明,经α-氯代萘处理后的聚苯硫醚原粉结晶速率常数有明显提高;聚苯硫醚/聚醚砜共混物的Avrami指数较纯聚苯硫醚低,共混物的结晶速率常数随共混组成变化出现最低值;共混物存在明显的二次结晶现象,t_(?)与t_(max)之间存在线性关系。