悬浮聚合法制备单分散聚硅氧烷微球

采用悬浮聚合法以正硅酸乙酯(TEOS)和甲基三甲氧基硅烷(MTMS)为主要原材料,制备球形度良好的单分散聚硅氧烷微球。并同时研究了反应体系中反应条件对微球粒径大小及其分布的影响。通过扫描电镜(SEM)、动态光散射(DLS)和红外光谱(FT-IR)等分析手段分别对微球的形貌、分布和结构等进行了表征。确定最优的反应条件为:同时满足温度为40℃且氨水浓度为0.01%时,微球呈球形度良好的单分散状态。     

不同尺寸单分散PMMA/GMA/DVB聚合物荧光微球的制备

采用无皂乳液聚合及种子无皂乳液聚合方法制备了200～800 nm四种不同尺寸的单分散PMMA/GMA/DVB (PMGD)复合微球. 用扫描电镜(SEM)和动态光散射(DLS)对粒径尺寸、形貌进行了表征. 实验发现单体滴加速度是影响种子无皂乳液聚合过程二次成核的关键因素. 用乙二胺对微球表面的环氧基团开环后, 通过在微球表面接枝树枝状PAMAM (d-PAMAM)达到微球表面的官能化的目的, 元素分析和红外光谱实验证明了微球表面d-PAMAM的存在. 最后利用微球表面的活性氨基与四甲基异硫氰酸罗丹明(TRITC)反应, 得到四种尺寸的水分散性的红色荧光微球.     

细乳液法制备聚硅氧烷-Ag纳米复合微球及其抗菌性

首先以苯乙烯(St)及3-甲基丙烯酰氧基三甲氧基硅烷(MPS)为反应单体,通过细乳液聚合制备表面功能化聚硅氧烷微球,然后利用该微球表面的硅羟基及硅氧烷基团对Ag+的吸附及还原作用原位制备聚硅氧烷-Ag纳米复合微球。采用透射电镜(TEM)、紫外(UV-Vis)、热重分析(TG)及X射线衍射(XRD)等对聚硅氧烷-Ag纳米复合微球的形貌和组成进行了表征。研究表明:改变MPS和硝酸银的用量可调控聚硅氧烷-Ag纳米复合微球的形貌及表面银含量;抗菌实验结果表明,聚硅氧烷-Ag纳米复合微球具有较好的抑菌性。     

阻抗蛋白质吸附载体微球的制备与性能研究

聚合条件对制备功能化微球起到至关重要的作用。在本文中,通过功能单体、烯丙基聚氧乙烯醚(APEG)和苯乙烯的分散共聚制备了一种阻抗蛋白质吸附的功能化微球;然后,通过红外光谱(FT-IR)、动态光散射(DLS)和扫描电镜(SEM)等手段分析这些功能微球的粒径、表面形态和性能;最后通过牛血清蛋白(BSA)吸附实验评价其阻抗吸附性能。实验结果表明：APEG兼具功能单体和稳定剂的功能,在合适的条件下,可以得到良好单分散性的微球。此外,每克聚(苯乙烯-烯丙基聚氧乙烯醚)(P(St-co-APEG))微球的BSA吸附量为0.66 mg,而每克聚(苯乙烯-甲基丙烯酸缩水甘油酯)(P(St-co-GMA))微球的BSA吸附量为4.8 mg。总之,通过分散共聚制备了一种阻抗蛋白质吸附的微球。     

溶胶-凝胶法制备单分散功能性二氧化硅球

采用溶胶-凝胶法一步制备单分散二氧化硅微球,该二氧化硅微球表面富集大量的官能团,提供反应活性位点。具体研究配料比、搅拌速度、电解质浓度对微球粒径的影响。通过加入具有官能团的硅烷从而得到功能性二氧化硅微球,可以用于生物样品分析检测。     

金纳米粒子簇的制备及表面增强拉曼光谱

建立了一种简单新颖的表面增强拉曼散射(SERS)基底制备方法.首先根据激光光束直径大小制备了与其相匹配的胶体微球阵列模板,再对模板进行等离子体刻蚀,然后采用金蒸汽进行气相沉积,最后将胶体微球剥离其基板,在微球的表面得到"单"金纳米粒子簇.胶体微球为直径2.6μm的聚苯乙烯微球,金纳米粒子直径平均约为300 nm,采用原子力显微镜(AFM)和扫描电子显微镜(SEM)对其进行了表征,并测试了其SERS光谱.测试结果表明,金的拉曼增强因子能够达到10~6.     

以碳微球为核的金纳米壳球体的制备

通过水热合成法制备了单分散碳微球, 并以此单分散碳微球为核, 利用其表面修饰的银纳米粒子作为种子, 进一步还原制备了以碳微球为核、以金为壳的金纳米壳(Nanoshell)球体. 通过透射电子显微镜和紫外可见吸收光谱对其形态以及光谱性质进行了表征. 研究结果表明, 采用该种方法制备出来的碳微球具有良好的单分散性, 表面修饰简便快捷, 利用碳微球为核制备的金纳米壳球体尺寸可控, 在近红外范围内有强吸收. 实验结果证明该方法是制备金纳米壳球体的一种有效新方法.     

光敏性单分散核-壳树莓状PSt/PAM微球制备

采用分散聚合两步加料法,在成核期后向反应体系加入光引发转移终止剂(photo-iniferter)单体2-N,N-二乙基二硫代氨基甲酰氧基乙酸β-甲基丙烯酰氧基乙酯(MAEDCA)制备了核-壳单分散光敏性聚苯乙烯(PSt)微球;进一步,在甲醇介质中,利用光敏性微球在紫外光辐照下引发单体丙烯酰胺(AM)进行表面沉淀接枝聚合,制得了表面亲水、树莓状(raspberry-like)PSt/PAM微球.采用SEM及TEM观察了所得微球的结构和形貌,FTIR、UV-Vis、1H-NMR及XPS分析表明微球的photo-iniferter基团含量随MAEDCA加入量增大而提高,同时补加一定量的MAEDCA、St、AIBN、甲醇及水时所得光敏性PS微球单分散性最好;微球表面接枝PAM后变得亲水并可大量吸附Ag纳米粒子.     

草莓型SiO2/PMMA纳米复合微球的制备

在纳米二氧化硅水分散体系中,借助于碱性辅助单体1-乙烯基咪唑(1-VID)与未改性纳米二氧化硅表面羟基之间的酸-碱作用,通过1-VID与甲基丙烯酸甲酯(MMA)的自由基共聚合,制备了草莓型的SiO2/PMMA复合微球.整个反应过程中,纳米二氧化硅无需表面处理,体系中无需另外加入乳化剂或助乳化剂,微球表面吸附的纳米二氧化硅对颗粒起稳定作用.用动态光散射粒度分布仪测得复合微球粒径在120-330nm之间,热重分析结果表明,复合微球中二氧化硅含量介于15%-20%之间.透射电镜和扫描电镜显示所得复合微球具有草莓型结构,二氧化硅富集在表面.     

多层聚合物微球及其功能性空心聚合物微球的研究进展

具有特殊组成和结构的单分散微球以其独特的性质和广泛的应用得到了广泛的关注。经过近几年的工作,本课题组利用蒸馏沉淀聚合法,合成出了一系列含有不同功能基团、组成和形状的单分散多层微球,进而制备了具有不同结构的功能性空心微球,并探讨了构建多层结构微球的机理。初步研究表明,这些功能性微球在可控药物释放、催化和微反应器等领域具有独特的性能和潜在的应用价值。本文概述了本课题组近五年来采用蒸馏沉淀法制备多层结构微球及其空心微球的研究进展。     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Hard and soft acids and bases: structure and process

Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).