应加快聚乙烯共聚单体１－己烯国产化

1－己烯是线性聚乙烯的重要共聚单体，也是高级增塑剂的重要原料。由于我国目前尚无1－己烯生产，所需要的1－己烯必须从国外进口，因而限制了１－己烯在我国的应用。目前我国线性聚乙烯基本上都是采用1－丁烯作为共聚单体，这是因为１－丁烯在国内价廉易得，但是，１－己烯共聚的线性聚乙烯树脂具有的优异性能是1－丁烯共聚的线性聚乙烯树脂难以比拟的。因此，从长远上看，１－己烯在我国的需求必然会有较大的发展。目前，我国共有HDPE7套（673kt／a）、LLDPE12套（1125kt／a），如果全部采用1～己烯，按HDPE添加量为3％，LLDPE添加量为8％计算，大约需１－己烯130kt／a；     

聚1-丁烯釜内合金的流变性能

采用恒速双筒毛细管流变仪研究了聚1-丁烯釜内合金的流变性能并将其与高全同聚1-丁烯(iPB)的流变性能进行了比较。结果表明,所合成的釜内合金熔体是一种假塑性流体,且随着测试温度的升高其非牛顿指数变大,非牛顿性减小。在相同温度和剪切速率下,釜内合金的粘流活化能小于iPB的粘流活化能;随剪切速率的升高,粘流活化能减小,其粘温敏感性降低。     

聚丙烯/聚(1-丁烯)釜内合金的合成与结构性能

以含内给电子体的二氯化镁负载四氯化钛催化剂,采用两段聚合工艺,在一段聚合形成的具有催化活性的聚丙烯颗粒上进行1-丁烯二段聚合,制备了高等规聚丙烯(iPP)/高等规聚(1-丁烯)(iPB)釜内合金材料.采用溶剂抽提分级法将iPP/iPB合金分为乙醚可溶物、正庚烷可溶物、正庚烷不溶物3种级份.采用傅里叶变换红外光谱、核磁共...     

一种催化加氢合成3-丁烯-1-醇的方法

在催化剂条件下,3-丁炔-1-醇在乙醇为溶剂加氢反应生成3-丁烯-1-醇,然后经精馏得到高含量的3-丁烯-1-醇。该方法工艺简单,操作方便且得率较高,对环境污染较小,因此具有广泛的应用前景。     

苯乙烯—1—丁烯共聚物合金的性能及微观结构

利用ＳＮ－１催化剂对苯忆烯－１－丁烯进行“原位”共聚合反应，分别采用同时加料和顺序加料两种共聚合反应方式制备了两大类苯乙烯－１－丁烯共聚物合金。结果表明，不论是哪种聚合方式，ＳＮ－１催化剂对苯乙烯－１－丁烯共聚合均表出现出较高的催化活性及单体转化率，所得共聚物合金具有高热软化温度和较发的物理性能。利用ＳＥＭ和ＴＥＭ对共聚物合金的微观观察结果表明，在共聚合反应过程中生成的共聚物对共物物合金的良好的增     

聚1-丁烯釜内合金的流变性能EI北大核心CSCD

采用恒速双筒毛细管流变仪研究了聚1-丁烯釜内合金的流变性能并将其与高全同聚1-丁烯(iPB)的流变性能进行了比较。结果表明,所合成的釜内合金熔体是一种假塑性流体,且随着测试温度的升高其非牛顿指数变大,非牛顿性减小。在相同温度和剪切速率下,釜内合金的粘流活化能小于iPB的粘流活化能;随剪切速率的升高,粘流活化能减小,其粘温敏感性降低。     

锌盐类成核剂对聚(1-丁烯)结晶性能的影响

采用偏光显微镜、差示扫描量热仪和傅里叶变换红外光谱仪等方法研究了降冰片烯二羧酸锌(NED-Zn)和ZnO成核剂对聚(1-丁烯)结晶及晶型转变的影响,并用Jeziorny法分析了聚(1-丁烯)的非等温结晶过程.结果表明,2种成核剂的加入使得聚(1-丁烯)的结晶温度升高、结晶速率加快,NED-Zn的成核效果优于ZnO.NE...     

镍二亚胺配合物-TiCl4复合催化剂制备新型乙烯/1-丁烯共聚产物结构性能研究

研究了三种负载型镍的二亚胺配合物与TiCl4组成的新型复合催化体系，在不同MAO，以烷基铝为助催化剂的条件下，催化乙烯／1－丁烯淤浆共聚制备的一系列塑性体和弹性体共聚物的结构性能。发现由于催化催化系具有齐聚及原位共聚性能，制得的共聚产物是一种高支化度（21.1-703.branch number/1000C)，低密度和极低密度（0.880g/cm^3-0.911g/cm^3)塑性体和弹性体共聚物。     

磁敏弹性体微结构扫描电镜表征原理剖析及前处理方法优化

对试样液氮脆断后进行扫描电镜观察是研究材料微观结构的常用方法,但应用于磁性羟基铁粉填充的磁敏弹性体试样时,却很难获得理想效果。通过对橡胶高分子结晶现象和低温脆断理论的分析,揭示脆断截面无法形成裸露的羟基铁粉链的机理;提出机械切割和抛光相结合的截面处理方法,得到的样品截面可满足扫描电镜对磁敏弹性体表面微结构的表征要求。通过对扫描电镜工作原理和成像理论的分析,阐述磁性材料产生的杂散磁场与扫描电镜磁透镜的磁场、入射电子束、收集器电压产生的耦合作用。这种耦合作用使在样品表面按一定时间和空间顺序做光栅式逐点扫描的入射电子束发生畸变,改变磁敏弹性体发射的二次电子的运行轨迹,使二次电子收集器收集效果变弱,降低图像质量。根据绝缘电阻测试得到不同体积分数羟基铁粉的磁敏弹性体的电导率,确定金属离子真空溅射和粘贴导电胶的试样处理方法。提出磁敏弹性体样品的退磁方案,并得到理想的微观形貌图像。     

Characterization of microstructure in stitched unidirectional composite laminates

The internal geometry of stitched uniaxial multiply carbon-fiber preforms is investigated experimentally. The microstructure is parameterized by such four introduced parameters as distortion length, distortion width, minor axis and major axis. The quantificational measurements are performed for these parameters under different stitch densities and different stitch threads. A theoretical model, called fiber distortion model, is developed to describe the spatial distribution of in-plane fiber misalignment angle and inhomogeneous fiber volume fraction induced by stitching.     

Characterization of the SiC and TiN whisker microstructure

Five criteria for evaluating the whisker microstructure have been suggested, which include (1) proportion of perfect single crystals, (2) morphology and growth direction, (3) length, diameter and ratio ofL/D, (4) the bulk and surface chemistries, (5) defects and their distribution. Three sets of commercially available SiC whiskers made in two countries and the TiN whiskers were characterized in terms of the above criteria.     

Highly efficient tungsten-substituted mesoporous SBA-15 catalysts for 1-butene metathesis

Tungsten-substituted mesoporous SBA-15 materials have been synthesized by using a direct co-condensation sol–gel method. These resultant materials have been characterized by X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), ²⁹Si MAS NMR and UV–Visible spectroscopy. Results of these analysis indicated that these materials had high surface area, uniform hexagonal channels and thick framework walls which were similar to that of SBA-15 and the tungsten species were highly dispersed in the silica-based framework structure. The tungsten-substituted mesoporous SBA-15 materials were used as catalysts for 1-butene metathesis for the first time, and they showed excellent catalytic performance. Such outstanding catalytic performance should be attributed to the proper content of tungsten species and its high dispersion.     

Characterization and microstructure of porous lead zirconate titanate ceramics

Porous lead zirconate titanate (PZT) ceramics are widely used because of their low acoustic impedance, high figure of merit and high hydrostatic sensitivity. In the present work, porous PZT ceramics were fabricated by incorporating polyethylene oxide (PEO) as pore-forming agent. Both PZT powder and PEO were mixed with a binder at different ratios and compaction was carried out. The samples were slowly heated to remove the pore-forming agent and binder without cracks, followed by controlled sintering and electrode forming. Samples were poled using corona poling technique. The ferroelectric properties and microstructure of the prepared ceramics were characterized. The correlation of porosity with microstructure and ferroelectric properties were discussed.     

Al2O3透明陶瓷显微结构的研究

采用高纯Al2O3(＞99.9%)粉末为原料,用无压烧结工艺制备Al2O3透明陶瓷.研究了添加剂Y2O3、烧结温度、保温时间等对Al2O3透明陶瓷显微结构和光学性能的影响.实验结果表明,适量的Y2O3能够抑制Al2O3晶粒的生长,改善烧结性能,但添加量过多会使Al2O3陶瓷气孔略有增加.在1800℃烧结的样品密度接近理论密度,具有较好的光学性能.延长保温时间能够使晶粒长大的同时有效排除晶界处少量气孔.     

Characterization of microstructure in laser surface modified alumina ceramic

Surfaces of alumina ceramic compacts were modified by irradiating with a high-power continuous wave laser to form a rapidly solidified continuous surface layer. A detailed characterization of the laser surface modified alumina using X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed a development of (110) crystallographic texture and a systematic evolution of surface microstructure in terms of surface grain size, porosity and roughness with laser processing fluence. Also, due to complexity of surface microstructures, a fractal based approach is suggested to completely describe the surface state of laser surface modified alumina. The results indicated that fractal dimensions of the surface microstructures can be effectively correlated with the surface features of laser surface modified alumina.