聚两性电解质及其水凝胶的研究进展

对近十年国内外在聚两性电解质及其水凝胶的合成、性质及在工业、生物医药方面的应用作了较全面的综述。     

反相微乳液中疏水缔合型聚丙烯酰胺的合成及其性能研究

在反相微乳液体系中合成了疏水缔合型聚丙烯酰胺 (HAPAM ) ,用Brookfield旋转粘度计测定了其水溶液性能 ,并与传统胶束聚合法制备的HAPAM作了比较 .结果显示 ,前者有更优越的耐盐和抗剪切性能 ,这主要是因为前者的大分子链上疏水共聚单体呈无规分布而后者呈嵌段分布 ,其疏水分子链以分子间而不是分子内缔合为主     

1,4,4‐Tri­methyl‐9‐phenyl‐8‐oxa‐9‐aza­bi­cyclo­[3.2.2]­non‐6‐en‐2‐one

The structure of the adduct of eucarvone with nitro­so­benzene, C₁₆H₁₉NO₂, is reported. The [3.2.2] bicyclic system corresponds to two seven‐membered rings in boat and distorted chair conformations and a six‐membered ring that adopts a distorted boat conformation. No conjugation is observed between the phenyl group and the N—O system. The packing is directed mainly by a C?O hydrogen bond, C—H?O‐(1 ? x, ?y, z) and by intermolecular C—H?π interactions.     

聚苯基硅氧烷与聚甲基苯基硅氧烷改性环氧树脂的合成与性能比较

热熔法制备了一系列聚苯基甲氧基硅氧烷(PPMS)、聚甲基苯基甲氧基硅氧烷(PMPS)改性环氧树脂,通过环氧值、红外光谱(IR)分析表明聚硅氧烷接枝了E-20环氧树脂且环氧基保持不变.探讨了有机硅含量对改性树脂固化体系耐热性能及韧性的影响.实验表明,当E-20环氧树脂与PPMS、PMPS的质量比为7∶3时,改性树脂固化体系的耐热性能明显提高,玻璃化转变温度(Tg)为95.8、88.3℃,分别比改性前提高了9.0℃和1.5℃;质量损失50%时的热分解温度(Td)为476.5、487.8℃,分别比改性前提高了58.3℃和69.5℃.与ED-30固化体系相比,EPMS-30固化物的耐热性能,韧性等力学性能提高的更加明显,并且还具有优良的涂膜性能.     

(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺反相微乳液共聚合特性研究

选用SPAN80与OP10复合乳化剂、K₂S₂O₈-Na₂SO₃氧化还原引发剂,进行(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺反相微乳液共聚合反应.研究了单体配比、电解质浓度和乳化体系的油水比对共聚物分子量及离子度的影响,考察了该共聚合体系的反应特性.     

石墨炉原子吸收光谱法测定大鼠血清中硒

通过考察不同基体改进剂效果,提出了以硝酸锶和硝酸钯做为混合基体改进剂。建立了用石墨炉原子吸收法测定牛血清和大鼠血清中痕量硒的分析方法。线性范围为0-120ng/mL,硒的检出限为0．095ng／mL,方法用于标准牛血清测定。结果与标准值基本吻合,大鼠血清测定标准加入回收率为102％。     

Erratum to: Evaluation of Three Multiresidue Methods for the Determination of Pesticides in Marijuana (Cannabis sativa L.) with Liquid Chromatography-Tandem Mass Spectrometry

Marijuana (non-medical cannabis) is a well-recognized psychoactive herbal drug used for recreational purposes. The aim of this work is to describe and compare the performance and suitability of selected methods to analyze pesticide residues in marijuana. The fitness of three typical pesticide multiresidue methods [acetate buffered QuEChERS (method A), a modified citrate buffered QuEChERS (method B) and citrate buffered QuEChERS (method C)] were tested in marijuana through the LC–MS/MS determination of 61 LC amenable pesticides. Considering recoveries at the highest level for the selected pesticides in marijuana, from the 61 target analytes, 37 (method A), 40 (method B) and 46 (method C) compounds gave accurate results (70–120 % range). Method C showed the best performance for the target analytes in terms of recoveries, precision, limits of quantitation and matrix effect. Marijuana showed to be a highly complex matrix. Most analytes suffered high signal suppression (ME <−50 %) for method B while medium (−50 to 20 %) to low (−20 to 0 %) signal suppression was found for methods A and C. Moreover, high coelution of coextractives with the target analytes was observed. A pilot survey with real samples revealed that seized and legally produced marijuana samples contained pesticides. Residues of diazinon (0.03 mg kg⁻¹), tebuconazole (0.19 mg kg⁻¹) and teflubenzuron (0.11 mg kg⁻¹) were simultaneously detected in one marijuana sample. The establishment of MRLs in a legal consumption scenario such as in Uruguay seems to be necessary in the near future.

     

ChemInform Abstract: Azidopentazole is Probably the Lowest-Energy N8 Species - A Theoretical Study.

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