利用叠氮基团的特殊反应活性合成含有C60基团的聚磷腈

C60以其独特的光、电、磁和生物活性等性能引起了人们浓厚的研究兴趣和热情,其中,C60的高分子材料化,即将C60基团连接到高分子上,成为高分子的一部分(主链或侧基),使所得到的高分子同时兼具C60的各种功能和高分子的良好加工性能,是C60走向实际应用的一条重要途径[1].     

樟脑锂引发的C60和对甲基苯乙烯的阴离子共聚

C60分子具有缺电子烯烃的化学特性,六元环间的6:6双键为反应的活性部位.可发生诸如氧化还原、亲电加成、络合和自由基加成等多种反应.共价富勒烯化学的系统发展使得C60这一三维建筑块具有了前所未有的多变性,而这一多变性则为合成技术上令人感兴趣的材料开辟了广阔的空间[1].如何将C60及其衍生物所表现出来的优异卓绝的光、电、磁等性质与其它材料(如高分子)的优良性能巧妙地结合起来,发展具有特殊光、电、磁性能的新型材料,开拓C60及其衍生物在信息工程、材料科学、生命科学、超导与光电子学、医药和催化、航空航天等方面的应用研究是当前最赋有挑战性的一项工作[2-4].与聚苯乙烯(PS)相比,聚对甲基苯乙烯(PPMS)的许多物理化学性能明显优于聚苯乙烯,是一类具有广泛应用前景的高分子材料.     

侧链上带有C60基团的聚苯乙烯的光电导性能

近几年来,可溶性高分子C60衍生物的合成已取得明显的进展.Weis等[1]报道了以C60封端的聚苯乙烯大分子衍生物,Hawker等[2]合成出聚苯乙烯C60的共聚物.这些单取代的C60衍生物很好地保持了C60原有的性质,加工性能和机械性能均较好.唐本忠等[3]用紫外光照射聚碳酸酯和C60溶液或在AIBN存在的条件下加热以上溶液,得到可溶的聚碳酸酯C60衍生物,该法产率很高(可达99%),且简单易行.Patil等[5]也用类似的方法通过自由基聚合将C60接枝到聚烯烃的高分子链上.我们已报道了将C60接枝到聚烯烃上所得到的共聚物的性能[5,6],但C60高分子衍生物的用途尚不清楚.     

含C60的苯乙烯和丙烯酰胺共聚物的合成与表征

在高分子领域中,C60的高分子化一直是C60材料化的一个重要途径.迄今为止,制备含C60高分子的方法有以下几种:(1)采用自由基引发剂、阴离子引发剂或阳离子引发剂引发C60与烯类单体共聚[1,2];(2)对C60进行表面修饰,引入可聚合官能团,合成含C60的单体,随后聚合成含C60的高分子[3];(3)制备出带有功能基团的高分子前体,再通过功能化反应将C60引入高分子链[4～9].     

由A2和CB2型单体合成端羟基超支化聚(脲-氨酯)

超支化聚合物是一类高度支化的具有三维椭球状立体构造的大分子[1]. 由于具有传统线型聚合物所没有的低熔体粘度、高流变性、良好的溶解性及大量末端官能团等一系列独特的物理化学特性, 超支化聚合物自 20世纪 80年代末在杜邦公司诞生以来[2]便很快成为高分子科学界研究的一个热点[3～7], 预计其将在医药载体、大分子建筑"砌块"、催化剂和流变添加剂等诸多领域得到广泛应用[8].     

C60腈胺类衍生物的合成及三阶非线性光学性质

C60的三阶非线性光学性质的研究是近年来富勒烯物理化学性质的研究热点之一[1].研究显示,尽管C60具有三维共轭的π电子体系,其本身并不具有大的三阶非线性系数[2,3].但由于C60分子具有较低的三重简并LUMO能级,显示出较强的电负性,能够与适当的给电子体形成相应的电荷转移体系,其三阶非线性系数可提高一至两个量级[3-6].本文通过合成C60的腈胺和双聚腈胺衍生物及其Fe(Ⅲ)配合物,对其三阶非线性光学性质及电荷转移作了初步探讨.     

含磷聚醚醚酮酮砜的合成与表征

聚芳醚酮(PAEK)具有优良的热性能、机械性能、电绝缘性能及耐化学药品性,在航空航天、电子电器、核能工业以及民用高技术领域有着广泛的应用[1].聚芳醚酮熔融温度高且难溶于一般有机溶剂,不易加工.为改善聚芳醚酮的溶解性和加工性,可采取在主链中引入大的侧基、柔性基团、扭曲的非平面结构和采用共聚等方法[2～5].     

在导电高分子薄膜表面沉积密度可控的银纳米粒子

<正>由于导电高分子的导电性和化学性质可以在导体和半导体区间内快速调节[1],因此其复合材料受到了越来越多的关注[2].金属纳米粒子在光电子器件、检测及传感等诸多领域表现出独特的性能[3],在生物技术领域中的重要性尤为突出[4].因此,如果将导电高分子和金属纳米粒子结合在一起,将有利于拓展导电高分子的应用范围.本文研究了银纳米粒子在聚苯胺薄膜表面的沉积行为,分别用原子力显微镜(AFM)和扫描电子显     

新型可溶性含氟聚芳醚酮的合成、表征及性能

制备了新型可溶性含氟聚芳醚酮高性能材料, 使该材料结合了含氟聚合物与聚芳醚酮两种材料的优点, 既具有很好的热稳定性、溶解性和阻燃性, 又有较低的介电常数和吸湿性[5,9,10]. 对于提高聚芳醚酮类材料的性能, 拓展其使用范围和加工方法具有很大的开发前景和实用价值.     

基于萘二胺和醚酮结构的高性能聚合物的合成

以聚酰亚胺、聚芳醚酮和聚甲亚胺等为代表的高性能高分子材料具有优异的物理化学性能,在航空航天、核工业以及微电子等领域得到了重要应用[1,2].在一些特殊行业需要聚合物具有良好的溶解     

用多官能链转移剂通过普通自由基聚合制备两亲性杂臂星形聚合物

以偶氮二异丁腈为引发剂,四(3-巯基丙酸季戊四醇四酯)(PETMP)为链转移剂进行甲基丙烯酸甲酯(MMA)的自由基聚合,得到了含有残余巯基的聚甲基丙烯酸甲酯大分子链转移剂(HS-PMMA).然后,以HS-PMMA作为大分子链转移剂进行甲基丙烯酸叔丁酯(tBMA)的自由基聚合,合成了杂臂星形聚合物.最后,将所得杂臂星形聚合物的PtBMA链段水解得到了两亲性杂臂星形聚合物.     

树枝状聚(醚-酰胺)基胶束的制备及其形貌研究

采用ε-己内酯(CL)开环聚合的方法首先合成树枝状聚(醚-酰胺)基(DPEA)星形聚合物star-PCL,再与异氰酸基封端的PEG(PEG-NCO)偶合制备了两亲性树枝状聚(醚-酰胺)基星形嵌段聚合物star-PCL-b-PEG.利用FT-IR、1H-NMR和GPC分析测试手段对star-PCL-b-PEG的结构进行了表征.通过滴加选择性溶剂的方法,制备了star-PCL-b-PEG以水为介质的类似"平头"聚集体胶束溶液.采用荧光光谱法测得star-PCL-b-PEG水溶液的临界胶束浓度(CMC)为1.623mg/L;采用激光光散射仪测得其在浓度0.15mg/mL和0.5mg/mL的流体力学半径分别为86.2nm和224.6nm,其多分散指数分别为0.115和0.197.透射电镜(TEM)观察发现胶束的形貌受共溶剂的特性,初始聚合物浓度,水含量等因素的影响.     

结肠酶特异响应性两亲高分子载体的合成和表征

合成了一种可在结肠部位被特异酶解的两亲性嵌段高分子,由聚丙交酯(PLA)疏水嵌段和聚乙二醇(PEG)亲水嵌段组成,两者通过5,5′-偶氮二水杨酸(OLZ)偶联,其中的偶氮键可被结肠部位的偶氮还原酶特异酶解.利用FTIR、NMR和GPC等方法表征了共聚物的结构,并通过透射电镜(TEM)和动态光散射(DLS)等方法研究了该高分子载体在水溶液中的组装行为.结果表明MPEG-OLZ-b-PLA可在水介质中形成尺寸在30nm左右的球形胶束,并在大鼠全盲肠提取液中被特异性酶解。     

模仿绿色荧光蛋白的荧光聚合物的合成和光学性质研究

受绿色荧光蛋白(GFP)荧光增强原理启发,采用开环聚合制备了两亲性聚乙二醇-生色团-聚己内酯(PEG-c-PCL)嵌段聚合物.通过核磁共振氢谱和碳谱(1H-,13C-NMR)、傅立叶变换红外光谱(FTIR)、凝胶渗透色谱(GPC)和紫外可见吸收光谱(UV-Vis)等证明其结构和性质.生色团和聚合物有相似的紫外吸收光谱,且最大吸收峰都在371 nm.荧光发射光谱表明,生色团的发射峰在427 nm,但聚合物的荧光发射峰出现了6 nm的红移,这是高分子化引起的结果.透射电镜(TEM)和动态光散射(DLS)证明了该两亲性嵌段聚合物能够组装成为纳米粒子.当聚合物组装成纳米粒子后,荧光强度增大了55倍,并且荧光发射峰出现了14 nm的红移,这些现象可归结于荧光生色团自由旋转的限制和组装导致的相互作用增强.     

Thermally induced changes in amphiphilicity drive reversible restructuring of assemblies of ABC triblock copolymers with statistical polyether blocks

ABC triblock copolymers in which a block with stimulus-dependent solvophilicity resides between solvophilic and solvophobic end blocks can undergo reversible transitions between different thermodynamically stable assemblies in the presence or absence of stimulus. As a new example of such a copolymer system, thermoresponsive poly(ethylene oxide)-b-poly(ethylene oxide-stat-butylene oxide)-b-poly(isoprene) (E-BE-I) triblock copolymers with narrow molecular weight distributions (M(w)/M(n): 1.05-1.18) were prepared by sequential living anionic and nitroxide-mediated radical polymerizations. The specific copolymers examined (9.0 ≤ M(n) ≤ 14.4 kg/mol, 14% ≤ wt % isoprene ≤35%) form near-spherical aggregates with narrow size distributions at 25 °C. The thermoresponsive behavior of these polymers was studied by applying cloud point, DLS, and TEM measurements to a representative polymer, E(2.3)BE(5.3)I(2.3). The transformation of polymer aggregates from spherical micelles to vesicles (polymersomes) at elevated temperatures was detected by DLS and TEM studies, both with and without cross-linking of polymer assemblies. The rate of transformation with E-BE-I systems is more rapid than that observed for poly(ethylene oxide)-b-poly(N-isopropylacrylamide)-b-poly(isoprene) assemblies, suggesting that interchain hydrogen bonding of responsive blocks after dehydration plays an important role in the kinetics of aggregate rearrangement.     

Nanoparticle agglutination: acceleration of aggregation rates and broadening of the analyte concentration range using mixtures of various-sized nanoparticles

SiO(2) particles of various sizes were prepared and surface modified with biotin-chain-end-functionalized poly(ethylene glycol). Dispersions of these particles were prepared, and their aggregation was induced upon the addition of avidin. The aggregate size and growth rate were monitored by DLS analysis, and SEM and TEM images of freeze-dried samples of the aggregate solutions were used to confirm the DLS data and to image the aggregate size and dimension. A linear correspondence between apparent diameter and time was observed, and both the 20 and 300 nm particles aggregated at slower rates than for the 40 nm particles. These observations were attributed to differences in the average functionality of the systems and the different initial concentrations of particles and avidin. The observed aggregation rates of binary combinations of the three particle sizes (i.e., 20 + 40 nm or 40 + 300 nm) were faster than those of the single-sized mixtures. These results were attributed to the faster flux of smaller particles toward larger particles in the mixture solutions as well as to the potentially larger number of productive collisions possible between mixtures of small particles and large particles versus only similarly sized particles. Combinations of the three sizes of particles were studied to find an empirical optimum formulation for generating large aggregates on a short time scale and over a wide range of analyte concentrations.     

活性自由基聚合法制备以C60封端的聚苯乙烯

通过活性自由基聚合的方法制备了以２,２,６,６－四甲基－４－羟基呱啶氮氧自由基（ＴＥＭＰＯＬ）封端的聚苯乙烯大分子,实验结果证明该反应体系是一个典型的活性自由基聚合体系,同时研究了ＴＥＭＰＯＬ／ＡＩＢＮ的比例及ＡＩＢＮ的含量对聚合反应的影响。用以ＴＥＭＰＯＬ封端的聚苯乙烯和Ｃ６０反应,制得了Ｃ６０的聚苯乙烯高分子衍生物,紫外和ＧＰＣ结果均证明Ｃ６０已连接到聚苯乙烯的长链上,ＧＰＣ的结果还证明,Ｃ６     

Micelles of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) with blended polystyrene core and their application to the synthesis of hollow silica nanospheres

Core-shell-corona (CSC) micelles of asymmetric triblock copolymer, poly(styrene-b-2-vinylpyridine-b-ethylene oxide) (PS-PVP-PEO), containing polystyrene homopolymer (homo-PS) in the core were successfully prepared in aqueous media. The influence of homo-PS contents over the formation of the micelles was investigated thoroughly by various techniques such as dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence spectroscopy. It was found that the size of the PS core of the micelle was increased by the addition of homo-PS as observed by DLS and TEM techniques. The SEM and TEM measurements confirm the spherical morphology of the micelles and enlargement of PS core over the addition of homo-PS. The increase in the PS core volume of the PS-PVP-PEO micelles is attributed to the insertion of homo-PS in the PS core. The micelles have also been demonstrated as facile soft templates for synthesis of hollow silica nanospheres. The average diameter of the spherical hollow particles could be tuned between 30.6 and 38.8 nm with cavity sizes ranging from 20.7 to 28.5 nm using tetramethoxysilane as silica precursors under mild acidic conditions. The facile synthesis of hollow silica using the CSC micelles with different homo-PS contents indicates that the hollow void size can be controlled within a range of several nanometers.     

ABA三嵌段离子型共聚物的合成及溶液自组装

以对二溴苄作引发剂,引发苯乙烯和甲基丙烯酸对硝基苯酚酯(NPMA)相继进行原子转移自由基聚合(ATRP),合成了3个三嵌段聚合物PNPMA-b-PS-b-PNPMA,其中聚苯乙烯段含有146个单元,PNPMA段的结构单元数分别为8、20和36.对这3个三嵌段共聚物分别进行水解反应及与2-氨基吡啶的取代反应,得到了具有相反电荷的PMAA-b-PS-b-PMAA和PNPMAAm-b-PS-b-PNPMAAm两种6个三嵌段共聚物.用核磁、红外和GPC表征了聚合物的结构、分子量及分子量分布等.将这两种三嵌段共聚物以等摩尔混合,在水中可自组装成碗形聚集体结构,讨论了可能的形成机理.     

Formation and morphologies of novel self-assembled micelles from chitosan derivatives

We successfully synthesized N-phthaloyl-carboxymethylchitosan (CMPhCh) from chitosan. CMPhCh could be self-assembled to form various morphologies of crew-cut micelle-like aggregates using a mixed solution of water and N,N-dimethylformamide (DMF). The results of scanning electron microscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS) revealed that the morphologies of the aggregates exhibited vesicles, vesicle-encapsulating vesicles, onion-like vesicles, and large compound micelles (LCM). Their morphologies were changed with varying the concentration of CMPhCh, the ratio of DMF in the mixture, and the self-assembly process. In relatively high CMPhCh concentration and content of DMF, CMPhCh was self-assembled to form the onion-like vesicles with a thin wall and 80-240 nm diameter. For the first time, TEM observation provided straightforward evidence of the onion-like vesicles prepared from natural polymer.