1,1,1-三羟基丙烷为核的三臂星型聚乙二醇合成及表征

以1,1,1-三羟甲基丙烷与过量癸二酸二乙酸酐反应,制得了端羧基的三官能度小分子核三癸二酸三羟甲基丙烷酯(TMP-SK3).在辛酸亚锡催化下,以二苯醚为共沸脱水剂,将三官能度小分子TMP-SK3作为偶联剂,进一步与不同分子量的端羟基聚乙二醇(PEG)和聚乙二醇单甲醚(PEGm)缩合,减压下共沸脱水,制备了以TMP-SK3为核,PEG或PEGm为臂的三臂星形大分子.通过1H-NMR,DSC,GPC,XRD等手段对所得聚合物进行了表征.DSC测试结果表明,与线型聚乙二醇相比,三臂星型聚乙二醇由于TMP-SK3核的存在,不仅影响聚乙二醇的结晶速度,同时也影响结晶的完善程度,导致其结晶温度和结晶熔融温度发生变化.     

Thermochemical, volumetric and spectroscopic properties of lysozyme–poly(ethylene) glycol system

Investigations of lysozyme–polyethylene glycol system were made by differential scanning calorimetry, fluorescence and density techniques. The values of unfolding enthalpies, ΔH_N^U, unfolding temperatures, T_m, excess molar heat capacities, ΔC_p, and apparent molar volumes, V_Φ , were determined as functions of PEG concentration. The three PEGs of average molecular mass (MW) 6000, 10000, 20000 were used as macromolecular crowding agents. The concentration of polymers was changed in the range 0–30% mass per volume (w/v). The values of ΔH_N^U remained constant with no dependence on PEG concentration, while PEG addition to buffered lysozyme solutions caused linear decrease of T_m. The values of ΔC_p and V_Φ of lysozyme dramatically changed in the range of 8–10% of PEG concentration. The fluorescence spectroscopy was used in order to investigate the polymer influence on possible solvent–lysozyme interactions. The electrical properties of polymer–water and polymer–buffer systems, the dielectric constants of solutions were determined with use of impedance spectroscopy.     

Liquid‐Phase Synthesis of 2‐Methyl‐2‐Aryloxypropanoic Acid Derivatives from Polyethylene Glycol) Supported 2‐Bromo‐2‐Methylpropanoate

An efficient liquid‐phase synthesis of 2‐methyl‐2‐aryloxypropanoic acid derivatives with good yields and high purity on soluble polyethylene glycol (PEG) has been developed by treatment of PEG‐bound 2‐bromo‐2‐methylpropanoate with phenoxides in the presence of a catalytic amount of NBu₄I and KI, and subsequent cleavage from the PEG.     

V‐shaped graft copolymers via triple click reactions: Diels–alder,copper‐catalyzed azide–alkyne cycloaddition,and nitroxide radical coupling

We report here a simple and universal synthetic pathway covering triple click reactions, Diels–Alder, copper‐catalyzed azide–alkyne cycloaddition (CuAAC), and nitroxide radical coupling (NRC), to prepare well‐defined graft copolymers with V‐shaped side chains. The Diels–Alder click reaction between the furan protected‐maleimide‐terminated poly(ethylene glycol) (PEG) and a trifunctional core ( 1 ) carrying an anthracene, alkyne, and bromide was carried out to yield the corresponding α‐alkyne‐ and α‐bromide‐terminated PEG (PEG‐alkyne/Br) in toluene at 110 °C. Subsequently, the polystyrene or polyoxanorbornene with pendant azide functionality as a main backbone is reacted with the PEG‐alkyne/Br and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO)‐terminated poly(ε‐caprolactone) using the CuAAC and NRC reactions in a one‐pot fashion in N,N′‐dimethylformamide at room temperature to result in the target V‐shaped graft copolymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4667–4674     

可降解PET/PEG共聚物的合成

利用聚合物法通过熔融缩聚直接合成了可降解的PET／PEG共聚物，通过红外光谱、色质联用分析对聚合反应机理进行了研究，讨论了聚合条件对聚合物分子量的影响，测定了聚合物的体外降解。     

Response surface methodology for the modelling of copper removal from aqueous solutions using micellar-enhanced ultrafiltration

Response surface methodology (RSM) was used to study the cumulative effect of the various parameters, namely surfactant (sodium dodecyl sulphate (SDS), anionic) concentration, pH, and surfactant/metal molar ratio and to optimise the process conditions for the maximum removal of copper from aqueous solutions via micellar-enhanced ultrafiltration (MEUF). For obtaining the mutual interaction between the variables and optimising these variables, a central composite design (CCD) by use of response surface methodology was employed. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant. The model was statistically tested and verified by experimentation. Values of pH at the range of ca. 7.5 were very successful for the separation. The maximum rejection coefficient of 98.4% was obtained for the following optimal conditions: SDS/Cu²⁺ molar ratio *r = 7.85, *pH 7.36, *C_surf = 6.82 g/l SDS. A modification of micellar-enhanced ultrafiltration for the removal of copper from aqueous solutions was studied by the implementation of sodium dodecyl sulphate–polyethylene glycol (PEG) aggregates. A full factorial design (FFD) was employed for studying the effect of molar ratio of surfactant/metal, pH and mass ratio of surfactant/polymer at a constant concentration of surfactant equal to 5 g/l. The comparison of the two systems in the region of their common factors showed that the addition of polyethylene glycol caused a slight increase in rejection coefficient of copper but also could function as ‘scavenger’ for surfactant species.     

Hydrothermal Synthesis of PEG-capped ZnS：Mn2＋ Quantum Dots Nanocomposites

Water-soluble Mn2＋-doped ZnS nanocrystals surface capped with polyethylene glycol（expressed as PEG-ZnS：Mn2＋） were synthesized in aqueous solution with PEG as surface modifier without ligand exchange.The particles were obtained via chemical precipitation method at 100 ℃ with an average diameter of 3 nm and a zinc blende structure.The PEG modified on the surface of PEG-ZnS：Mn2＋ nanocrystals rendered the nanocrystals water soluble and biocompatible.And the PEG-ZnS：Mn2＋ nanocrystals have the potential application in molecular assembly and biological fluorescence analysis.The effects of the Mn2＋ concentration,stabilizer concentration,and synthesis time on the photoluminescence（PL） intensity of ZnS：Mn2＋ QDs were also investigated.     

PEG掺杂对钙钛矿太阳能电池的影响

为了提高钙钛矿太阳能电池的能量转化效率,减小回滞现象,研究了聚乙二醇(PEG)掺杂钙钛矿太阳能电池阳极修饰层PEDOT∶PSS对器件性能的影响。通过电容-电压(C-V)测试分析了PEDOT∶PSS修饰层和钙钛矿层之间的界面电荷积累情况,通过电流密度-时间(J-T)瞬态光电流的测量研究了修饰层和钙钛矿层之间缺陷态情况。结果表明,PEG掺杂阳极修饰层提高了器件的短路电流(J_(sc))、开路电压(V_(oc))和填充因子(FF),光电转化效率从7.5%提高到10.0%,光电转化效率提高了33%,经过掺杂后的器件回滞现象明显减弱。这种通过PEG掺杂PEDOT∶PSS的方法能够减少器件界面处的电荷积累和缺陷态,从而减小器件的回滞现象,提高器件的能量转化效率。     

可降解聚合物包覆次血红素六肽微球的制备及生物活性

采用水包油包水(W₁/O/W₂)复乳溶剂挥发法制备了包覆次血红素六肽(DhHP-6)的2种聚酯微球. 通过扫描电子显微镜、 体外缓释行为、 高效液相(HPLC)检测、 酶活力测定和初步的动物实验等表征, 综合评价了载药微球的体外释放及体内生物活性. 实验结果表明, 载药微球球体圆整, 粒径分布均匀, 载药量高, 能够实现体外缓释, 并对细胞过氧化损伤和小鼠脑缺血损伤均有一定的保护作用.     

PEG-grafted PVA Membrane and Its Blood Compatibility

Preparation and blood compatibility of different shape polyvinyl alcohol(PVA) membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene(PTFE) capillary as supporter] PVA membranes were prepared; then, methoxy polyethylene glycol(mPEG) was grafted onto the surface of the PVA membranes. The effects of the shape, structure and properties of the membrane surface on blood compatibility were studied in detail. The experiment results show that mPEG modified PVA membranes, especially mPEG modified tubular membrane, could availably repel the adhesion of the platelets. In addition, the anticoagulant mechanism of mPEG with a steric repulsion effectiveness was confirmed further via different grafting methods.