超声波合成温敏型聚合物——聚(N-异丙基丙烯酰胺)

以N-异丙基丙烯酰胺为单体,N,N′-亚甲基双丙烯酰胺为交联剂,THF为溶剂,采用超声辐照聚合法合成了一种温敏型聚合物——聚(N-异丙基丙烯酰胺)(1),其结构经FT-IR表征.用UV-Vis研究了1的热相转变性能.结果表明,1具有温度敏感性,其最低临界共溶温度为34℃.     

双敏感性环糊精超分子聚集体的制备及其性能研究

利用光敏感性环糊精衍生物与温度敏感性聚合物主客体间的包结络合作用制备了具有光/温度双敏感性的环糊精超分子聚集体. 首先制备了主体分子光敏感性4-羟基肉桂酸-β-环糊精(4HCA-CD); 再以末端带金刚烷基团(AD)的三硫酯作为链转移剂, 用可逆加成-断裂链转移自由基聚合(RAFT)法制备温度敏感性双臂聚合物AD-PNIPAM-AD; 用傅里叶变换红外光谱(FT-IR)、核磁共振氢谱(¹H NMR)证明了化合物的结构. 利用β-CD的疏水空腔和AD之间的络合性能, 制备了4HCA-CD/AD-PNIPAM-AD双敏感性超分子复合物, 通过二维核磁(2D NMR)对其包结性能进行了探究, 结果证实金刚烷包结于环糊精的空腔中. 所得4HCA-CD/AD-PNIPAM-AD复合物具有光敏感性, 用紫外光照射后, 复合物的分子量增大近一倍. 而且, 4HCA-CD/AD-PNIPAM-AD复合物可以自组装形成超分子聚集体, 其粒径随温度的升降发生可逆的减小或增大.     

N-异丙基丙烯酰胺-丙烯酰胺热敏凝胶的溶胀特性

制备并表征了N-异丙基丙烯酰胺-丙烯酰胺热敏凝胶(NIPAm-Am),研究了单体配比、引发剂、交联剂用量和温度对其溶胀特性的影响。结果表明：NIPAm-Am热敏凝胶是由亲水和疏水基团组成的非晶高聚物。mAm／mNIPAm越大,凝胶的平衡溶胀率越大;增加交联剂的用量,凝胶的溶胀率减小,当引发剂的质量分数为0．008时溶胀率达最大值;温度的增加会使凝胶的溶胀率减小,在相转变温度时,溶胀率的变化最大。     

TEMPERATURE-SENSITIVE LATEX PARTICLES FOR IMMOBILIZATION OF α-AMYLASE

Poly(methyl methacrylate-co-N-isopropylacrylamide-co-N-acryloxysuccin-imide) (poly(MMA/NIPAAni/NAS)) latex particles were prepared by emulsifier-free emulsion polymerization. The latex particles could reversibly flocculate and disperse when the solution temperature was kept above and below the characteristic lower critical solution temperature (LCST). The LCST of the latex dispersion could be adjusted lower or higher by increasing or decreasing, respectively, the ionic strength of the solution.α-Amylase was immobilized onto the latex particles by reacting with the succinimide groups on NAS. It was demonstrated that the ct-amylase immobilized latex particles could be separated by thermoflocculation. After 5 repeated thermocycles, 83 % of the latex particles could be recovered, and the apparent enzymatic activity could be retained as high as 78percnt;.     

温度敏感型磁流体热磁对流特性研究

建立了描述外磁场作用下温度敏感型磁流体热磁对流特性的数学模型,数值模拟了回路中热磁对流的流动与传热特性.搭建了磁流体热磁对流回路装置,采用粒子示踪测速技术(PIV)测量了磁流体的流速,用热电偶测量了磁流体的温度分布.通过实验值和数值模拟结果,分析了不同磁场大小、不同热负荷,以及不同冷却温度下回路的运行特性.     

低场固体NMR研究纳米复合凝胶结构与动力学

纳米复合水凝胶复杂的微观结构和动力学决定了其宏观性能,阐明其结构和动力学的非均匀性对揭示凝胶相变机理、认识其宏观物理和化学性质和设计新型高分子凝胶都具有重要意义.通过合成不同粘土含量的系列聚异丙基丙烯酰胺(PNIPAm)/锂藻土纳米复合水凝胶,运用多种先进的低场固体NMR技术详细研究了凝胶微观结构和动力学的非均匀性.首先建立了分析多组分凝胶体系中刚性和柔性高分子组分相对含量的计算方法,然后在不同粘土含量下,通过测量凝胶FID信号和质子T1定量研究了凝胶中刚性和柔性高分子组分的相对含量;通过偶极滤波双量子NMR实验,研究了体系中与交联密度关联的残余偶极作用参数随黏土含量的变化.结果表明:在纳米复合水凝胶中,随着粘土含量的增加,凝胶中聚合物的刚性相增加,而柔性相下降,当粘土含量达到12%(Wclay/Wwater)时体系中的刚性相含量趋于平衡.多量子实验结果表明,随着粘土含量的增加,纳米复合水凝胶中高分子链的残余偶极作用参数逐渐增大,反映了体系中高分子链的受限运动和二维无机纳米片层形成的物理交联密度增大的趋势.     

相分离免疫分析的研究进展

相分离免疫分析通过开展快速的均相反应和简单的异相分离而兼具了均相免疫与异相免疫的优点,方法易于实现自动化.本文介绍了相分离免疫分析的基本原理,对相分离免疫分析载体、固定化方式、标记物、应用及发展方向进行了评述.引用文献60篇.     

Polarity and Temperature-Dependent Properties of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacryl-amide) Hydrogels Studied by Liquid Chromatography

Summary: Superporous N-isopropylacrylamide (NIPAAm) and N,N-diethylacrylamide (DEAAm) copolymers with N,N'-methylenebisacrylamide (MBAAm) were prepared by radical polymerization with the aim to determine their temperature-dependent changes in polarity by liquid chromatography. Superpores were formed by the salt-leaching technique using NaCl as a porogen. Porosities of the hydrogels characterized by water regain and mercury porosimetry, ranging from 81 to 91%, were proportional to the volume of NaCl porogen in the feed. The retention volumes of several phenols decreased with increasing temperature as polarity of the hydrogels decreased. A jump change in solute retention volume was observed at ca. 32 °C in PNIPAAm and at ca. 35 °C in PDEAAm indicating a change in the mechanism of interaction. The Gibbs energy changes ΔG_CH2 were rather low, increasing in the order phenol < benzyl alcohol < ethanol < butan-1-ol. In contrast to the solutes, retention volumes of bovine serum albumin and dextrans were higher at higher temperature confirming thus hydrophobic interactions of the compounds with the studied hydrogels.     

微凝胶增强两性复合水凝胶的制备与性能

将核壳微凝胶包埋在两性基质中,制备了复合水凝胶(CAH)。 研究发现,利用微凝胶与聚合物链之间的物理缠结作用,可以使复合凝胶具有致密的网络结构,力学性能显著提高;复合凝胶对pH和离子强度敏感,呈现出典型的两性聚电解质凝胶的溶胀行为。 同时微凝胶的存在和特殊的复合结构,可赋予CAH两性凝胶基质所不具有的响应性,并实现在高温下快速响应。     

高比能电池新材料与安全性新技术的研究进展 Ⅰ.锂离子电池自激发安全保护机制

安全性问题是阻碍大容量和高功率锂离子动力电池应用的关键.本文以作者课题组近期研究工作为主,简要介绍了几种旨在提高锂离子电池安全性的自激发安全保护机制,包括氧化还原穿梭剂、电压敏感隔膜、温度敏感电极、阻燃性电解液,并分析了这些方法的应用特点.