抗高温蠕变高粘红性共聚酰亚胺应变胶研究

采用两苯酐间连接不同桥基的几种二元酐，与二元胺经溶液共聚合成共聚酰胺酸，两种不同结构的共聚酰胺酸共混再配加适量酚醛树脂，制成棕黄色透明粘稠应变胶。用其胶膜在不同温度下进行热亚胺（固）化反应，测试了形成的半互穿聚合物网络的粘接、蠕变等性能，其中粘结力和抗蠕变性突出。制成的箔式电阻应变计，经老化和蠕变测试达到并超过国空标准高等级指标。     

采用流变学方法研究聚酰胺酸6FDA-TFDB溶液的降解行为

合成了一种聚酰胺酸6FDA-TFDB溶液,利用流变仪研究其在不同影响因素(如:温度、升温速率、溶剂含水量等)下的流变行为,发现聚酰胺酸溶液的降解在高温区和低温区存在不同的行为.通过Andrade公式获得不同条件下聚酰胺酸溶液的黏流活化能,并比较其差异,同时对溶剂水含量在不同温度区域下对聚酰胺酸降解速率的影响也进行了深入的分析,从而建立一种半定量比较不同条件下聚酰胺酸溶液降解速率的方法.     

氧化硅担载的氧化铌/氧化铝的酸性

含有两种不同氧化物的二元氧化物,其物理和化学性质往往明显不同于其单组分氧化物,这在理论上是有意义的.目前已有两种类型的二元氧化物用于工业.第一类是制成混合氧化物,两组分在体相中均匀分散,这些二元氧化物(如SiO_2-Al_2O_3)以其酸性著称,并主要用作酸性催化剂或双功能担体.第二类二元氧化物是一种表面相氧化物,我们采用这个词是指将一种氧化物以单层或少于单层覆盖在另一氧化物表面上的物质.Murrell和Yates报道的氧化钛-氧化硅系统就是一个例子.     

苯胺链段为侧基的聚酰胺酸的合成及性质

采用三元共聚法制备了苯胺齐聚物为侧链的接枝型聚酰胺酸. 通过红外光谱、核磁共振谱及高效凝胶渗透色谱等技术对聚合物结构进行了表征. 该材料亚胺化后具有十分优异的热稳定性. 紫外-可见光谱和电化学测试结果表明, 该聚合物具有独特的光谱性质和可逆的电化学活性. 聚酰胺酸/ITO电致变色电极具有颜色变化明显, 响应速度较快, 着色效率高等优点, 是一种综合性能较好的电致变色聚合物材料.     

聚酰亚胺硅氧烷/聚酰亚胺两面异性复合膜的制备及性能研究

以氨丙基封端的聚二甲基硅氧烷(PDMS)、 4,4'-二氨基二苯醚(4,4'-ODA)和3,4,3',4'-联苯四酸二酐(s-BPDA)为原料, 合成了聚酰胺酸硅氧烷嵌段共聚物. 将此嵌段共聚物和聚酰胺酸(s-BPDA/4,4'-ODA)共混, 通过控制制膜条件, 利用各组分在不同溶剂中的溶解度的差别, 使聚酰亚胺硅氧烷富集在膜的上表面. 因为两相在结构和性质上的相似性, 当聚酰胺酸硅氧烷和聚酰胺酸混合时, 具有很好的相容性, 消除了两相间的界面, 从而制备了优异的聚酰亚胺硅氧烷/聚酰亚胺两面异性的复合膜材料. 利用X射线光电子能谱(XPS)和水滴接触角对此复合膜进行了表征, 证明了此复合膜的两面异性, 并对此复合膜进行了热性能和机械性能研究, 发现此薄膜保持了聚酰亚胺优异的性能.     

含氟聚酰胺酸亚胺化反应动力学

利用动态热重法研究了两种含氟聚酰胺酸薄膜在连续升温过程中的亚胺化反应动力学.采用积分法确定了两种含氟聚酰胺酸的亚胺化反应动力学函数是g(α)=(1-α)-1-1(其中:α为转化率);分别由Ozawa、KAS和迭代法来求取反应的活化能Ea值.结果表明:由KAS法或迭代法求得的活化能比较可靠.在此基础上得出相关的动力学参数、动力学模型方程和动力学补偿效应表达式,为聚酰亚胺工艺参数的选择和工艺窗口的优化提供了理论依据.     

4-二氰亚甲基-2,6-二甲基-4H-吡喃衍生物的合成及其 荧光效应

两种新的4-二氰亚甲基-2,6-二甲基-4H-吡喃衍生物及对应的聚酰胺酸被合成和表征。该聚酰胺酸在普通有机溶剂中具有良好的可溶性。报道了这些生色团衍生物的光强度、量子产率和发射波长,以及生色团共价键合所形成的聚酰胺酸膜具有比对应的生色团单体更强的荧光效应。     

PLLA-TMC微球增强磷酸钙骨水泥的制备与性能研究

以左旋丙交酯（L-LA）和三亚甲基碳酸酯（TMC）为原料,辛酸亚锡为催化剂,采用本体聚合法制备了不同单体配比的二元无规共聚物（PLTMC64, PLTMC73和PLTMC82）,其结构和性质经¹H NMR, FT-IR, GPC和DCS等表征。采用水包油法将3种二元PLLA-TMC共聚物制成平均直径约50 μm的微球,以5 wt%含量加入到磷酸钙骨水泥中进行固化时间与力学性能测试。结果表明：添加PLTMC73微球为增强相时,骨水泥压缩强度增高到22 MPa左右,且压缩模量能达到1.5 GPa。 SEM照片显示,骨水泥与微球之间有较好的亲和性。      

碳化钨用作质子交换膜燃料电池催化剂载体的抗氧化性能

 采用还原碳化法制备了碳化钨样品,并用原位还原法担载Pt粒子得到Pt/WxCy催化剂. 利用计时电流技术对Pt/WxCy和常规Pt/C催化剂进行氧化处理,并用循环伏安法测试了氧化前后两种催化剂的电化学活性面积. 将两种催化剂制成单电池,对比研究了其氧化后的性能衰减. 结果表明, Pt/WxCy催化剂制成的单电池抗氧化能力显著高于普通Pt/C制成的单电池.     

硒碲的阴极溶出伏安法测定(Ⅱ)

近来,曾报导利用在电极上共沉积生成金属间化合物的作用来提高电化学溶出伏安法的灵敏度和选择性。硒与铜或碲与铜共沉积于铂电极和石墨电极上能生成二元金属间化合物,在悬汞电极上这两对元素也存在共沉积现象并且已用于测定硒或硒与碲。我们研究了在酸性氯化铵-硫酸铵底液中,硒、碲在汞电极上与铜的共沉积作用,认为于-0.25和-0.5伏电解时硒与铜生成两种不同组成的二元金     

高效率变色WO3多聚体/1，10-DAD自组装薄膜的制备

A novel high-efficient photochromic self-assembly multilayered film has been fabricated from WO3 and 1,10-DAD solution using molecular deposition technique.The dependence of photochromic behavior on with WO3 in the WO3-polymer/1,10-DAD self-assembly film was discussed in comparison with WO3/4,4-BAMBp system.The results clearly show that organic molecules determine the charge density of the photo-induced charge-tracsfer complexes,andthus manipu-late the structure and the photochromic properties of the films.     

High Performance Polyimide with High Internal Free Volume Elements

This paper reports a new polyimide design with high internal free volume elements for fast mass transport simultaneously with high selectivity. Here, we show that the polymer design using a three‐dimensional rigid molecular structure having internal void space can lead to the formation of high fractional free volume with proper cavity size to separate small gas molecules with high selectivities as high permeabilities. These findings could strongly impact emerging gas separation applications using polymeric membranes such as natural gas purification and biogas purification to get clean energy resources.

     

Preparation of High Efficiency Columns for High Performance Liquid Chromatography

Abstract

This method employs a specially constructed slurry reservoir, which features an internal taper and a quick-disconnect pump fitting. A major innovation is the use of a three-solvent system to maintain a slurry of packing material as a ‘slug’ within the reservoir. A measured amount of carbon tetrachloride is poured into the empty reservoir-column assembly. The column packing material is introduced as an isopropanol slurry and the reservoir is filled with isooctane. The assembly is then connected to a Haskel DSTV 122C pump, and the column is packed with isooctane at 10,000 psi pressure.

This procedure provides HPLC columns with efficiencies of 40,000 plates per meter for 10-micron silica, 30,000 plates per meter for 10-micron C₁₈, and 70,000 plates per meter for 5-micron C₁₈ packing materials. We have used this method for preparation of over 35 HPLC columns during the past two years.     

高性能聚苯并噁嗪树脂

聚苯并噁嗪树脂作为一种新型酚醛树脂,不仅具有优异的耐热性和阻燃性,而且克服了传统酚醛树脂在成形固化过程中释放小分子的缺点,在制备高性能材料方面已引起研究者的广泛关注。本文综述了近年来国内外为制备高性能化聚苯并噁嗪树脂所作的一些研究工作,包括从主链或侧链中引入苯环等刚性官能团、在主链或侧链中引入可聚合官能团、与另一种高分子形成共混或共聚物以及与其他材料复合形成复合材料等,并对该树脂材料的工业开发前景、国内外研究现状以及发展趋势进行了分析。     

高通微量分析

本文讨论了微量水平的高通量分析问题,认为这是当前生命科学向分析化学所提出的最主要的挑战,也是分析化学发展必须解决的核心问题之一.探讨了发展高通微量分析的一般策略和一些相关现存方法.着重讨论了表面等离子体共振成像分析方法的特色和发展情况,认为该方法可能是一种特别适合于生物样品潜在的多功能高通微量分析新方法.     

Fed-Batch Enzymatic Saccharification of High Solids Pretreated Lignocellulose for Obtaining High Titers and High Yields of Glucose

1-Deoxynojirimycin (DNJ) is an efficient α-glucosidase inhibitor (α-GI) with potential applications in the prevention and treatment of diabetes. In this study, 16 Bacillus strains were screened for α-GI rate, and the strain HZ-12 with the highest α-GI rate was identified as Bacillus amyloliquefaciens through the analysis of physiological biochemical characteristics and 16S rDNA sequence. By LC-MS/Q-TOF analysis, the α-GI component produced by B. amyloliquefaciens HZ-12 was identified as DNJ. Soybean was used as the substrate for the solid-state fermentation; 870 mg/kg DNJ was produced by B. amyloliquefaciens HZ-12 after optimizing the fermentation conditions and media, which was 3.83-fold higher than the initial yield. Also, evaluations of nutraceutical enrichment in the form of anticoagulant activity, antioxidant activity, total nitrogen (TN), and total reducing sugars (TRS) of the B. amyloliquefaciens HZ-12 fermented soybeans were substantially higher than unfermented soybeans. This study provided a promising strain for high-level production of DNJ and produced nutraceutical enriched soybeans by fermentation.     

High resolution thermogravimetry

A new thermogravimetric instrument is introduced, Hi-Res^TM TGA 2950. The Hi-Res^TM TQA gives a significant improvement to TG results. The instrument control parameters are varied as a function of the sample's rate of weight change. This novel feature improves resolution and reduces analysis time. The maximum heating rate and resolution index are user selectable.Data presented demonstrate improved resolution for survey TG thermal curves and very high resolution for difficult to resolve complex materials. Results are demonstrated for many types of samples including: homopolymers, polymer blends, inorganic reference materials, and complex organic mixtures.Hi-Res trademark and patent applied for by TA Instruments, Inc.

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Zusammenfassung Es wird das neue thermogravimetrische Gerät Hi-Res^TMTGA2950 vorgestellt. Mit Hilfe von Hi-Res^TMTGA2950 ergibt sich eine eindeutige Verbesserung der TG-Resultate. Die Kontrollparameter des Gerätes werden als eine Funktion der Massenänderungsgeschwindigkeit der Probe geändert. Diese neue Eigenschaft verbessert die Auflösung und verringert die Analysenzeit. Maximale Aufheizgeschwindigkeit und Auflösungsindex können vom Anwender bestimmt werden.Die dargelegten Daten zeigen eine verbesserte Auflösung der TG-Kurven und eine sehr hohe Auflösung für schwer aufzulösende komplexe Substanzen. Es werden Ergebnisse für zahlreiche Beispiele gegeben: Homopolymere, Polymergemische, anorganische Referenzsubstanzen und komplexe organische Gemische.Das Warenzeichen Hi-Res und das Patent wurde von TA Instruments,Inc. beantragt.

     

High resolution HPLC

In order to justify its classification as a “high resolution” technique, HPLC should show an improvement in efficiency by a factor of at least 10, should be easily achievable with separation times of less than 1 h, preferably in the reversed phase mode. This is accomplished by coupling three 25 × 0.46 cm columns packed with 5 μm spherical ROSiL-C₁₈-D silica gel. Details of the method and some typical chromatograms are given.