环氧烷烃开环聚合新催化剂——稀土络合催化聚合新进展

环氧乙烷、环氧丙烷和环氧氯丙烷等环氧烷烃的均聚物和共聚物是一类早为人们熟知且有着广泛用途的高分子。例如高分子量(10万到500万)聚环氧乙烷(也称聚氧化乙烯)可以用作胶粘剂、水溶性薄膜、纺织浆料增稠剂、润滑剂、流动减阻剂、絮凝剂、分散剂及药物添加剂等。环氧丙烷和环氧氯丙烷的均聚物和共聚物则是具有耐油、耐溶剂、耐寒、     

环氧丙烷-环氧乙烷-环氧丙烷嵌段共聚醚P_x E_(39) P_x系列的合成与结构表征

本文用常压合成方法制备了中央嵌段为39个环氧乙烷单位的环氧丙烷-环氧乙烷-环氧丙垸三嵌段共聚醚P_xE_(3(?))P_x系列;用凝胶渗透色谱法(HPGPC)与质子核磁共振法(′HNMR)表征系列的嵌段组成;用小角X射线衍射(SAXD)、低频拉曼光谱、差示扫描量热法(DSC)研究了系列的固态结构形态。研究表明:固态的P_xE_(3(?))P_x共聚醚系列由单层晶片堆集而成,非折迭的分子鏈在片中的取向一般是傾斜于片的端面。     

端活性聚丙二醇对环氧树脂的增韧改性

以端羟基聚丙二醇为基础合成了端羧基和端环氧基聚丙二醇,对不同端基聚丙二醇改性环氧树脂体系进行了DSC、DMA、冲击性能和冲断面SEM研究。随聚丙二醇端活性基与环氧树脂反应性的增强,固化体系更倾向于形成均相结构,环氧树脂固化物玻璃化温度降低更多。端羟基和端环氧聚丙二醇都能明显提高环氧树脂的冲击强度。综合分析测试结果表明聚丙二醇是通过增塑方式对环氧树脂进行增韧,而端环氧基聚丙二醇是通过提高交联网络柔性的方式对环氧树脂进行增韧。     

聚环氧乙烷-聚丙交酯嵌段共聚物的合成

以自制-缩二乙二醇单甲醚钾为引发剂,利用阴离子聚合原理,进行了环氧乙烷的开环聚合,得到了分子量为2 000,分子量分布为1.07和一端是甲氧基一端是羟基的窄分布聚环氧乙烷(mPEO).然后利用得到的mPEO作为大分子引发剂,在Sn(Oct)2催化作用下,引发D,L-丙交酯开环聚合,得到两亲性mPEO-b-PLA嵌段共聚物,其分子量分别为5 250,14 070,23 360和44 300,分子量分布分别为1.45,1.47,1.53和1.59.对目标产物和中间产物进行了表征,分子量与设计结果吻合,聚合是可控的.     

环氧氰凝地面防腐耐磨涂料试验研究

采用一种新型活性催化剂，在常温下制备环氧－丙烯酸酯，用－ＯＨ聚醚与多异氰酸酯预聚体与之制成互穿网络涂料，并讨论了环氧－丙烯酸酯／聚氨酯的比率和选用不同环氧－丙烯酸酯对涂层性能的影响。试验表明，互穿网络涂料的物理性能和耐化学腐蚀性均有较大提高。     

差示扫描量热法研究环氧端基酚酞聚芳醚酮的固化特性

为了提高环氧树脂的力学性能和耐热性能,制备了环氧端基酚酞聚芳醚酮,并研究其固化反应.由酚酞和4,4,-二氟二苯酮经芳香亲核缩聚反应,制得了含酚氧钾端基的聚芳醚酮低聚物.将其与环氧氯丙烷反应得到环氧值为0.13、数均分子量为1 540的含环氧端基聚芳醚酮.利用差示扫描量热法研究了以4,4＇-二氨基二苯醚为固化剂制备的环氧封端酚酞聚芳醚酮的固化反应和反应动力学特征.结果表明,固化反应为复杂反应,反应过程中体系放热,反应放热峰的起始温度和峰顶温度随着升温速率的增加而升高;该环氧体系的最低固化反应温度和固化反应峰顶温度为120.6℃和146.8℃,固化反应表观活化能和固化反应级数分别为68.21 kJ/mol和0.91.     

绿色阻垢剂环氧琥珀酸聚合物的研究进展

随着人类环保意识的不断提高,绿色高效阻垢剂的合成与应用是水处理领域研究的发展趋势。阐述了绿色阻垢剂聚环氧琥珀酸及环氧琥珀酸共聚物的研究现状与阻垢机理,针对聚环氧琥珀酸在阻垢性能方面存在的问题,展望了环氧琥珀酸共聚物的研究前景。     

聚环氧琥珀酸的研究进展

聚环氧琥珀酸是一种无氮、非磷有机化合物,兼具阻垢缓蚀双重功效．对聚环氧琥珀酸的发展现状、合成方法及其影响因素、阻垢与缓蚀性能进行了综述,同时指出了发展前景．     

聚羧酸超塑化剂的性能研究

研究了含有亲水性羧基、酸酐基团、磺酸基、聚环氧乙烷侧链的三种羧酸类共聚物对水泥浆体流变性能和水泥粒子表面Zeta电位的影响,并与萘系高效减水剂进行了对比.在改善水泥浆体的流变性能方面,三种聚羧酸超塑化剂的最佳掺量和饱和掺量均为0.3%～0.45%;对水泥粒子表面Zeta电位的影响方面聚羧酸超塑化剂远小于萘系高效减水剂,证实了两类减水剂的分散作用机理的区别.     

丙烯在甲醇-双氧水中的溶解度

钛硅分子筛催化丙烯环氧化是一条生产环氧丙烷的清洁工艺,其多相反应体系的相态研究是优化该反应体系的基础.利用可视相平衡仪在不同条件下测量了丙烯在甲醇-双氧水中的溶解度.结果表明,体系温度、双氧水有效质量浓度和甲醇含量是影响丙烯溶解度的关键因素.在双氧水∶丙烯∶甲醇摩尔比一定、温度相同且体系均为气-液-液三相平衡的条件下,30％（质量分数）双氧水氧化体系甲醇相中丙烯的溶解度低于50％（质量分数）双氧水氧化体系.在双氧水有效含量不同的两种氧化体系中,当甲醇含量较低时,体系呈现为气-液-液三相平衡,在30～60℃范围内可通过升温提高丙烯的溶解度;提高甲醇含量到一定程度时,体系液相在较低的温度下即可呈均相,为丙烯环氧化提供良好的反应环境.     

La2O3和CeO2的制备及催化臭氧氧化对氯硝基苯

为提高单独臭氧氧化去除水中有机污染的能力,分别以La(NO3)3.6H2O和Ce(NO3)3.6H2O为前驱体,采用水解沉淀法制备La2O3和CeO2粉体,利用X射线衍射、N2吸附、扫描电镜以及红外光谱分析技术对样品的晶相结构、粒径大小、比表面积、孔容、孔径分布以及表面官能团等进行表征.以蒸馏水配制的对氯硝基苯溶液(pCNB)为目标物,考察La2O3和CeO2的催化臭氧氧化活性.结果表明,La2O3和CeO2对pCNB的吸附作用有限,20 min的吸附率分别为6.7%和9.9%.臭氧对pCNB的去除能力有限,反应20 min的去除率仅为37.2%,以La2O3为催化剂时,去除效果有明显增加,反应20 min时去除率为82.1%,而以CeO2为催化剂时,去除效果反而没有O3单独氧化效果好,20 min时的去除率仅为24.3%.     

氧化钐掺杂对氧化锌压敏陶瓷电学特性的影响

以氧化锌、氧化镨、氧化亚钴、氧化铬和氧化钐作为原料,经配料、球磨、造粒、压片和烧结等工序制得压敏电阻片,采用电流-电压特性测试、X射线衍射和扫描电子显微镜分别获得陶瓷的电性能参数,材料成分和微观结构图.实验结果表明:随着氧化钐含量的增加,氧化锌压敏陶瓷的非线性和压敏电压呈现先增大后降低的趋势.当氧化钐摩尔百分比低于0.3时,非线性系数和压敏电压随氧化钐含量的增加而增大.而氧化钐摩尔分数为0.3%时,压敏陶瓷具有最佳非线性电学特性,非线性系数为35,压敏电压为435伏/毫米;继续增加氧化钐至摩尔分数为0.5%时,非线性系数和压敏电压将会降低.氧化钐绝大多数聚集在晶界层,抑制晶粒生长,从而提高了压敏陶瓷的压敏电压.而极少数氧化钐与氧化锌发生置换反应,降低了氧化锌颗粒的电阻,从而提高了非线性.因此氧化锌压敏陶瓷因掺杂氧化钐提高了电性能而有望应用在高压领域.     

由锌焙砂制备活性氧化锌的研究

以锌焙砂为原料，经氨浸，除杂，沉锌，干燥，煅烧等工序制取了活性氧化锌．采用正交设计确定制备过程的最佳技术条件，使锌的浸出率达95％以上，总回收率达90％．产品中活性氧化锌的含量为99．4％，比表面积为75m^2／g，产品质量达到HG／72572-94一等品标准．该工艺具有操作简单、稳定、可靠、适应性强以及锌的转化回收率高、“三废”少、环境污染小、成本低、产品质量好等特点．     

Gate oxide punching thru mechanism in plasma dry etching

The punching thru mechanism of gate oxide (thickness about 15A) was investigated. Because of the thin thickness of gate oxide, gate oxide punching thru may easily happen during the plasma process. It was found that what caused the punching thru was not only the selectivity of poly-silicon/oxide but also the pattern topography. We used the basic SRAM pattern to check this topography effect, and found that gate oxide located at the narrow spacing of two parallel serpentine lines was the most easily punched thru. What caused the topography effect was the starvation of oxygen in these places which were induced by the residue of poly-silicon and enhanced by electron shading effect. So, to solve the issue of gate oxide punching thru, firstly the selectivity should be enough, secondly we should pay attention to the etching pattern topography. Supported by the National High-Tech Research and Development Program of China (“863” Project) (Grant No. 2006AA843134) and the National Basic Research Program of China ("973" Project) (Grant No. 2007CB935302)     

高分子辅助沉积法制备氧化物和氮化物薄膜

高分子辅助沉积法是近年来发展起来的一种薄膜沉积方法。该方法利用高分子与金属键合形成均匀稳定的溶液,将溶液涂覆在基片上后,通过热处理使高分子分解而形成薄膜。该文介绍了使用该方法制备的一些具有代表性的氧化物和氮化物薄膜,包括简单氧化物/氮化物,如TiO2、GaN和AlN等,复杂氧化物/氮化物如(Ba,Sr)TiO3、Ti1-xAlxN等。通过X射线衍射、透射电镜、介电测试和光学测试等方法对薄膜的结构和性能进行了表征和分析,并探讨了基片和工艺条件对结构和性能的影响。这些结果表明高分子辅助沉积法可以广泛应用于制备各种高质量的氧化物和氮化物薄膜。     

Surface analysis of chemical stripping titanium alloy oxide films

The chemical stripping method of titanium alloy oxide films was studied. An environment friendly solution hydrogen peroxide and sodium hydroxide without hydrofluoric acid or fluoride were used to strip the oxide films. The morphologies of the surface and cross-section of the oxide films before and after the films stripping were characterized by using scanning electron microscopy (SEM). The microstructure and chemical compositions of the oxide films before and after the films stripping were investigated by using Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS). It was shown that the thickness of the oxide film was in the range of 5-6 μm. The oxide films were stripped for 2 to 8 min in the solution. Moreover, the effect of the stripping time on the efficiency of the film stripping was investigated, and the optimum stripping time was between 6-8 min. When the stripping solution completely dissolved the whole film, the α/β microstructure of the titanium alloy Ti-10V-2Fe-3Al was partly revealed. The stripping mechanism was discussed in terms of the dissolution of film delamination. The hydrogen peroxide had a significant effect on the dissolution of the titanium alloy anodic oxide film. The feasibility of the dissolution reaction also was evaluated.     

聚乙烯醇/纳米氧化锌复合材料的性能

为了改善聚乙烯醇的性能,通过熔融挤出的方法制备了聚乙烯醇/纳米氧化锌复合材料.采用力学性能测试、热分析、X射线衍射和紫外光谱研究了纳米氧化锌对聚乙烯醇力学性能、热稳定性、结晶性能和紫外屏蔽性能的影响.结果表明:复合材料的拉伸强度和断裂伸长率分别在纳米氧化锌含量为1.0wt%和0.5wt%时达到最大值,拉伸强度比纯聚乙烯醇提高了20.27%,断裂伸长率略高于纯聚乙烯醇;当纳米氧化锌含量为2.0wt%时,复合材料失重10%的温度比纯聚乙烯醇提高20℃;纳米氧化锌显著提高了聚乙烯醇的耐光老化性能,同时使聚乙烯醇中产生了新的晶相.纳米氧化锌的加入有助于多种性能的改善.     

Surface characteristics and structure of oxide films containing Ca and P on Ti substrate

The oxide films were obtained in an electrolyte of calcium glyeerphosphate (Ca-GP) and calcium acetate (CA) by mieroare oxidation (MAO). The oxide films displayed a porous and rough structure on the film surface, and the roughness tended to increase with inereasing voltage of mieroare oxidation. The oxide film exhibited a uniform coating and tends to be well boned to the substrate. The thiekness of oxide films depended on the final voltage at a eonstant concentration of eleetrolyte solution. Ca and P were also incorporated into the oxide film during the mieroarc oxidation process, It was found that the electrolyte of ealeium glyeerphosphate ( Ca-GP) and ealeium acetate (CA) was suitable for microarc oxidation to form oxide film eontaining Ca and P on Ti substrate. The eoneentration of Ca and P were 11.6 at% and 6. 4 at% , respectively, when microare oxidation was performed in the electrolyte of 0. 06 M Ca-GP and 0. 25 M CA at current density 50 A/m^2 and final voltage 350 V. The composition of the Ca, P and Ti changed during depth profiling. The crystalline phases were only anatase when final voltage was below 300 V and rutile was presented when voltage was up to 350V. The microstructure, phase structure and phase composition were investigated by scanning electron microscopy (SEM) , atomic foree microscope (AFM) , energy dispersive X-ray mieroanalyser (EDX) , and X-ray diffraction (XRD),     

Electrochemical performance of nickel oxide／KOH／active carbon super-capacitor

The fabrication and characterization of new type Nickel oxide/KOH/Active carbon super-capacitor have been described. Porous nickel oxide was prepared by hydrolysis of nickel acetate and heated in air at 300℃. The resulting nickel oxide behaved as an electrochemical capacitor electrode with a specific capacitance (50-70 F/g) superior to most active carbon electrodes. This kind of nickel oxide maintained high utilization at high rate of discharge (i.e., high power density) and had excellent cycle life more than 1 000 times,while the capacitance of the cell composed of two identical nickel oxide electrodes was poor at high discharge current density and the maximum operational voltage of this type capacitor was limited to 0.5 V. A new type super-capacitor was designed in which the nickel oxide and the active carbon were applied to the positive and negative electrodes respectively. The breakdown voltage of this type super-capacitor was improved effectively to 0.8 V and excellent characteristic of high power discharge was attained in this way. The Nickel oxide/KOH/Active carbon super-capacitor has promising potentials in portable telecommunications, uninterruptable power supplies and battery load leveling applications.     

Nafion/Silicon Oxide Composite Membrane for High Temperature Proton Exchange Membrane Fuel Cell

Nafion/Silicon oxide composite membranes were produced via in situ sol-gel reaction of tetraethylorthosilicate （TEOS） in Nafion membranes. The physicochemical properties of the membranes were studied by FT-IR,TG-DSC and tensile strength. The results show that the silicon oxide is compatible with the Nation membrane and the thermo stability of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. Furthermore, the tensile strength of Nation/Silicon oxide composite membrane is similar to that of the Nation membrane. The proton conductivity of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. When the Nation/Silicon oxide composite membrane was employed as an electrolyte in H2/O2 PEMFC, a higher current density value （1 000 mA/cm^2 at 0.38 V） than that of the Nafion1135 membrane （100 mA/cm^2 at 0.04 V） was obtained at 110 ℃.