苯乙烯-p-乙烯基苯甲酸两亲性嵌段共聚物在乙醇中自组装行为的电镜观察

两亲性嵌段共聚物在只对其中一链段为良溶剂的选择性溶剂中 ,能够自组装形成胶束 .胶束的形态和尺寸大小依赖于两链段的性质 ,共聚物的组成、浓度、溶剂的性质等[1] .这一性质使得嵌段共聚物在分子识别、药物和其他物质的输送、基因疗法、水系涂料、污染物的除去、纳米复合材料的制备、催化剂以及传感器等方面展示着潜在的应用前景 .因此 ,两亲性嵌段共聚物的合成及其在选择性溶剂中的自组装行为的研究近年来颇受关注[2 ] .依据两链段的比例不同 ,嵌段共聚物可形成星状胶束和“板寸头”(Ｃｒｅｗ ｃｕｔ)型胶束[3 ] .当可溶段远比不溶段长时…     

Biexponential C spin-lattice relaxation behavior of the crystalline region of ethylene copolymers and its origin

In this work, two series of ethylene-dimethylaminoethylmethacrylate (EDAM) and ethylene-methyl acrylate copolymers (EMA) with different comonomer content were studied by high-resolution solid-state ¹³C NMR spectroscopy. Biexponential ¹³C spin-lattice relaxation behaviors of the crystalline region were observed for all copolymer samples either melt-quenched or isothermally crystallized. The relative content of the shorter ¹³C T₁ component to that of the longer ¹³C T₁ component was found to increase with comonomer content. By employing a new pulse sequence which can be considered as a combination of Goldman-Shen's and Torchia's pulse sequences, it was demonstrated that the shorter ¹³C T₁ component is corresponding to the intermediate part of the crystalline region. The thickness of the intermediate part is estimated to be about 0.85 nm.     

Kinetic studies and analytical application of cholesterol oxidase and peroxidase immobilized to synthetic polymer

A method for individual and simultaneous covalent immobilization of cholesterol oxidase and peroxidase to copolymer of acrylonitrile with acrylamide is described. The effect of immobilization on the catalytic properties of the covalently bound enzymes was studied. The immobilized enzymes showed no change in pH optima and an increase in temperature optima, activation energy, and K _m , compared to data received from experiments with soluble enzymes. A small glass column packed with immobilized multienzyme complex was used to develop a method for manual determination of cholesterol in foodstuffs (e.g., in mayonnaise “Olinease”). The method was characterized by high analytical precision (coefficient of variation = 2.67%). The results show high correlation with those obtained by the Kageyama method (r=0.986). The method is economical (the enzyme-carrier conjugate may be used more than 300 times), precise, easy to perform, and less time-consuming than the manual methods utilizing soluble enzymes. The established manual method can be proposed for cholesterol determination in foodstuffs.     

Mixing state of amphiphilic di-block copolymer/homopolymer blends

Summary The mixing state of amphiphilic di-block copolymers consisted of poly(ethylene oxide) and poly(methacrylate) having azobenzene moieties in the side chains p(EO)₁₁₄pMA(Az)₂₄ and poly(ethylene oxide) p(EO)₁₁₄ was investigated from the viewpoints of isothermal crystallization and nano-scale ordered structure. The chemical potential, which required establishing the constant crystal growth rate, decreased with the p(EO) content up to 60%. The hexagonal packed cylinder structure was observed for the blends with the p(EO) content up to 60% and the lattice spacing of (100) and (110) planes increased with the p(EO) content up to 60%. The blends of amphiphilic p(EO)₁₁₄pMA(Az)₂₄ and p(EO)₁₁₄ were miscible without in the p(EO) content below 60%.     

高温热处理对偏氟乙烯-四氟乙烯共聚物高次结构的影响

聚偏氟乙烯(PVDF)及其一些共聚物,例如偏氟乙烯-四氟乙烯共聚物(PVDF/TFE)经过处理后呈现较强的压电性。许多研究表明它们是铁电聚合物,而且压电活性与样品的高次结构有关。松弛谱是研究结晶高聚物的高次结构的有力工具,近来,Koizumi等人报道了PVDF/TFE的热处理与松弛现象的关系。本文作者也报道了     

刚性链嵌段共聚物的研究（Ⅳ）──聚醚醚酮／苯酞圈型聚芳醚砜有规嵌段共聚物的合成与部分性能

以聚醚醚酮（ＰＥＥＫ）和苯酞圈型聚芳醚砜（ＰＤＣ）齐聚物为原料，通过溶液缩聚法制备了ＰＥＥＫ／ＰＤＣ有规嵌段共聚物系列样品。经ＤＳＣ、ＷＡＸＤ、ＴＧＡ、ＤＭＡ等方法研究表明：共聚物没有微相分离现象；其结晶属于简单正交晶系，ＰＤＣ含量对共聚物结晶行为产生很大影响；热稳定性随ＰＤＣ含量增加而明显降低；共聚物具有优异的力学性能，拉伸强度和储能模量高于ＰＥＥＫ。     

环氧乙烷和环氧丙烷共聚物及其LiClO4复合物的热性能

用ＤＳＣ研究了环氧乙烷和环氧丙烷共聚物（ＥＯ／ＰＯ）及其ＬｉＣｌＯ＿４复合物的组成与热性能的关系，结果表明，结晶熔融热溶随ＰＯ的增加而减少，同时，结晶度下降，电导率上升；Ｏ／Ｌｉ＝２０的试样在２次升温中产生冷结晶；热历史影响聚合物的热性能。     

共聚物铑配合物催化甲醇羰基化速控步骤的理论研究

采用以原子重叠及电子离域的分子轨道理论ＡＳＥＤ ＭＯ（含原子对排斥的ＥＨＭＯ法）为基础的结构自动优化法，对共聚物铑配合物催化甲醇羰基化制乙酸反应速率控制步骤 氧化加成进行了理论研究．计算了不同共聚物配体形成的铑催化剂与碘甲烷的氧化加成反应途径，并得到反应活化能，分析了氧化加成反应过程中的电子转移和空间因素对活化能的影响，计算结果与实验结果是相符的，并从理论上解释了２ 乙烯基吡啶形成的共聚物铑配合物催化活性高于４ 乙烯基吡啶形成的共聚物铑配合物催化活性的原因．     

Microemulsion elastomers

ABA-triblock copolymers bearing polymerizable methacrylate end-groups are covalently crosslinked in the droplet phase of W/O- and O/W-microemulsions. The resulting microemulsion elastomers combine the structure and the phase behavior of microemulsions with solid state properties such as elasticity or stability of shape. These new materials are characterized with the help of conductivity, dynamic-mechanical and dynamic light-scattering investigations. The influence of the chemical crosslinking process on the phase behavior and the dynamics of the underlying microemulsion is discussed.Dedicated to Prof. Dr. Hans-Friedrich Eicke on the occassion of his 65th birthday