Polymer coated sensor array based on quartz crystal microbalance for chemical agent analysis

Quartz crystal microbalance (QCM) gas sensors based on polymeric material were fabricated and their gas response characteristics were examined for four simulant gases of chemical agents, which were dimethyl methyl phosphonate (DMMP), N,N-dimethylacetamide (DMA), 1,5-dichloropentane (DCP) and dichloroethane (DCE). For the selection of appropriate coating materials, both principal component analysis (PCA) and hierarchical cluster methods were applied to a data set collected from 15 QCM sensors for 12 analytes. Four appropriate coating materials were selected after optimizing the correlation between the 15 coating materials and the first four principal component (PC) factors. The four chosen polymers were used as sensitive component for a sensor array, and then PCA is adapted to classify four simulant gases. The results show that the QCM sensor array has high sensitivity and selectivity to four chemical agents.     

分散聚合技术及其研究进展

介绍了分散聚合体系中各组分及反应条件对反应过程和最终产物性能的影响,简要归纳了分散聚合成核机理、稳定机理及其反应动力学,并着重阐述了近年来分散聚合发展的新技术以及制备的功能微球在各领域的应用等方面的研究进展.分散聚合与其它非均相聚合方法相比,是制备粒径范围在1-10μm且单分散性较好的聚合物微球的有效方法.最近,许多新思路不断引入分散聚合体系,如采用水和超临界CO2作为分散介质,尝试微波和辐射引发聚合以及按照活性聚合机理进行反应等.     

环境友好型消毒抗菌剂——二溴海因

二溴海因是一种高效、广谱、低残留的新型环境友好型消毒抗菌剂.介绍了二溴海因的结构、性质、抗菌机理、生产工艺与应用等.     

均匀增粘剂在橡胶阻尼材料中的应用

本文对均匀增粘剂的作用机理和应用进行了研究。结果表明:均匀增粘剂可显著降低橡胶阻尼材料胶料的门尼粘度,改善混炼胶体系的混炼工艺、分散性和降低胶料相的尺寸,提高相态稳定性,优化了产品的表观质量,对橡胶阻尼材料的力学性能和阻尼性能影响不大。当用量为4份时,可达到加工性能和使用性能的最佳平衡。     

水溶剂法合成聚丙烯酸系混凝土减缩剂的研究

根据减缩剂的作用机理及分子结构设计原理,用水溶剂法合成了聚丙烯酸系混凝土减缩剂(SRA-PA),对影响酯化反应和聚合反应的因素进行了探讨,并用红外光谱表征了其分子结构。通过实验得到SRA-PA的最佳合成条件:酯化反应催化剂用量为聚乙二醇单甲醚1200(MPEG)用量的5%,反应温度100℃,反应时间4h,丙烯酸(AA):MPEG=3:1;聚合反应聚乙二醇单甲醚丙烯酸酯(PEA):甲基丙烯酸甲酯(MMA)=2:3,过硫酸铵(APS)用量为单体总质量的2.5%。通过砂浆的收缩与强度测试等方法研究SRA-PA的主要性能,研究表明掺SRA-PA的砂浆减缩率3d达到50%~60%、28d达到20%~30%,同时不降低砂浆的强度。     

绿色纺织印染络合剂马来酸-丙烯酸共聚物的合成

以马来酸（MA）、丙烯酸（AA）为主要单体,采用水溶液聚合法制备了马来酸-丙烯酸共聚物,探讨了影响分散力和螯合力的因素．最佳合成条件为m（MA）：m（AA）=1：3,聚合温度80～90℃,以Na2S2O8和NaHSO3为引发剂,引发剂用量（m引发剂／m总单体）为3％,产品对MnO2的分散力为1．35g·L^-1,对CaCO3的螯合力为168mg·g^-1．     

Dynamic mechanical and dielectric relaxation characteristics of microcellular rubber composites

An in‐depth study of the surface characteristics of novel conductive carbon black Ensaco 350G has been carried out using XPS and high‐resolution vacuum FTIR. Both methods showed the existence of oxygen containing surface groups like carboxyls, carbonyls, etc. Dynamic mechanical analysis and dielectric relaxation spectra of conductive carbon black (Ensaco 350G) reinforced microcellular EPDM composites were used to study the relaxation behavior as a function of temperature (?90 to +100°C) and frequency (100–10⁶ Hz). The effect of filler and blowing agent loadings on dynamic mechanical and dielectric relaxation characteristics has been investigated. The effect of filler and blowing agent loadings on glass transition temperature was marginal for all the composites (T_g value was in the range of ?37 to ?32°C), which has been explained on the basis of relaxation dynamics of polymer chains in the vicinity of fillers. The variation in the real and imaginary parts of the complex impedance with frequency has been studied as a function of filler and blowing agent loading. Additionally, an in‐depth study of the surface characteristics of the filler using XPS, high‐resolution vacuum FTIR and Raman spectra is also reported. Copyright © 2008 John Wiley & Sons, Ltd.     

取代芳酰胺型β成核剂TMB5的形态演变规律及其对iPP的β晶诱导行为的影响

采用示差扫描量热、偏光显微镜、X-射线衍射、热重分析及红外光谱分析等手段,研究了以TMB5为代表的取代芳酰胺型β成核剂在不同加工条件下的形态演变规律及其对i PP的β诱导结晶行为的影响.结果表明,TMB5虽然没有明确的熔点,但其原始晶体可以在升温中逐渐熔融并在降温时形成较细的棒状形态;而TMB5对i PP结晶的诱导作用主要和其在i PP熔融体中产生的二次形态密切相关:在保证TMB5分解不明显的温度条件下,混炼温度的提高有利于TMB5在冷却过程中形成更为细小的棒状形态,使PP中β晶的相对含量提高;在混炼之后的二次加工成型过程中,较低的熔融温度和较慢的降温速度有利于β晶含量提高.     

Modification of Kagan's amide for improved activity as Chiral Solvating Agent in enantiodiscrimination during NMR analysis

A modification is proposed in Kagan's amide in order to improve its ability to offer stronger hydrogen bonding and hence better ability to bind with substrates. Introduction of chlorine in the amide aromatic ring along with the two nitro groups, increases the acidic character of amide hydrogen and makes the hydrogen bond stronger, the concept is tested by making three derivatives of Kagan's amide and the effect is confirmed by nmr analysis. The modified chlorinated Kagan's amides were then tested as chiral solvating agents for detection of optical purity of several types of substrates where the supramolecular recognition is measured by in situ nmr analysis. Several guest molecules such as amide, sulfoxide, epoxy-keto, hydroxy acid, diacid and phosphoric acid were scanned for this study and its efficiency is further established by comparison with samples of known optical purity.     

Iron oxide nanoparticles-loaded hyaluronic acid nanogels for MRI-aided Alzheimer's disease theranostics

Despite eye-opening advances in developing novel therapeutics for hard-to-treat diseases, treatment of Alzheimer's disease (AD) is still known as the challenge of generations. By the way, scrutinizing and shedding light on a major cause of AD, i.e., fibrillation of β amyloid (Aβ) peptides, have paved the way to find an effective therapy for this life-threatening disease in the foreseeable future. In this study, we endeavored to push forward with research on AD therapy, even as much as an inch, by fabricating and evaluating a theranostic system based on iron oxide nanoparticles-loaded hyaluronic acid nanogels (Fe₃O₄-HyA NGs). Fe₃O₄ nanoparticles were fabricated via a facile co-precipitation method and were loaded in HyA NGs in situ by formation of NGs using a thiolated HyA (HyA-SH) precursor. Standard structural analysis was performed on Fe₃O₄-HyA NGs, and the results revealed the NGs were negatively charged, which led to relatively poor adsorption of plasma proteins, and sized at the range of 120–150 nm. Also, Fe₃O₄-HyA NGs showed a superparamagnetic property with a magnetic saturation of about 62.8 emu/g indicating the successful loading of Fe₃O₄ nanoparticles. Besides, findings of the cytotoxicity analysis could primarily show the NGs did not pose a noticeable risk to normal astrocyte cells (i.e., 96.7% cell viability at 100 µg/ml after 48 h treatment). Moreover, in vitro magnetic resonance imaging (MRI) analysis could reveal the noticeable potential ability of the Fe₃O₄-HyA NGs to generate negative contrast by reducing both T2-weighted and T2*-weighted MR signal intensities with a relaxation rate (r₂) of about 120.87 (1/mM.sec). Finally, Fe₃O₄-HyA NGs exhibited a potential ability to impede Aβ aggregation by around 44% at 10 µM; also, they could induce disaggregation of Aβ fibrils by about 13% at 10 µM. Hence, Fe₃O₄-HyA NGs could be a promising choice for AD theranostics and could be further scrutinized in vitro and in vivo.