聚烯烃填充共混改性材料的研制

研究了高密度聚乙烯（ＨＤＰＥ）、低密度聚乙烯（ＬＤＰＥ）、线性低密度聚乙烯（ＬＬＤＰＥ）、聚丙烯（ＰＰ）等聚烯烃塑料的共混改性以及用碳黑、赤泥、硅灰石、粉石英等填料的填充改性效果。实验结果表明，两种高聚物及某些填料品种在一定配比情况下，可以在一定程度上改善共混材料的机械性能，同时还能降低材料成本，具有工业应用推广价值。     

耐温150℃的辐射交联阻燃聚烯烃热收缩材料

介绍了一种耐温150℃的辐射交联阻燃聚烯烃热收缩材料的配方、制备工艺及其性能.采用LDPE作基材,添加适量EVA改善LDPE与阻燃剂的相容性,加入10%～30%的EPDM提高热收缩材料的柔软性并降低辐射剂量.经共混、挤出造粒、加工成型制得的制品再经辐射,可在150℃下长期使用,其径向收缩率为51%,拉伸强度为10.2MPa,体积电阻率为7.2×104Ω·cm,氧指数为30,可用于航天、航空、汽车、军工等线缆的绝缘保护.     

辐射交联150℃阻燃聚烯烃热收缩材料的研制

本文介绍了一种辐射交联150℃阻燃聚烯烃热收缩材料的配方研究,制备工艺及性能,通过确定聚烯烃热收缩材料制备工艺,挤出温度、辐照剂量,制备出耐温达150℃,氧指数达30的热收缩材料,此材料可在150℃温度下长期使用,具有耐高温、机械、电性能优异、阻燃性能好,可广泛使用在航天、航空、汽车、军工等线缆的绝缘保护。     

高交联多相聚合物热收缩材料的研究

研究了高交联多相聚合物热收缩材料的配方及性能,讨论了配方及辐照剂量对材料的收缩性能和物理性能的影响,得出了高交联多相聚合物不仅有良好的物理性能,而且有理想的热收缩性能,可用作电缆附套材料。     

超细CaCO3制备聚烯烃填充母料

介绍了以超细ＣａＣＯ３制备聚烯烃填充母为的生产原材料、工艺、配方及设备。     

聚烯烃填充母料的研制

以LDPE为载体,滑石粉和CaCo_3为填料,分别以钛酸酯和铝酸酯作偶联剂,对滑石粉和CaCO_3进行活化处理,制成高填充聚烯烃母料。并对其以不同的配比填充PE时的物理机械性能和流动性进行了研究。     

聚烯烃的填充改性

本文综述了聚烯烃填充改性用填料和填料处理剂的主要品种以及改进聚烯烃填充复合材料性能的主要技术。用于聚烯烃改性的填料主要有碳酸钙、云母、滑石、硅灰石等十余种。所用处理剂分表面活性剂和偶联剂两类。前者如高级脂肪酸及其酯等；后者主要有硅烷类、钛酸酯类、铝酸酯类等。填料与聚合物之间的界面结构是影响填充复合材料性能的主要因素。通过表面活性剂或偶联剂处理、聚合物包复或表面接枝等技术可以改变填料表面的化学和物理性质，从而改善聚烯烃填充体系的相容性和界粘合力，起到改善和提高复合材料性能的作用。     

电应力控制热收缩材料的研制

采用PE与α-聚烯烃及其它助剂、填料共混,并经辐射交联制成了体积电阻率为1×10~(10)Ω·cm,介电常数为32,并具有热收缩性的电应力控制材料。试验和分析了PE与α-聚烯烃的配比,各助剂用量及加工工艺等对材料力学、电学性能的影响。     

Preparation and Characterization of Barium Titanate Suspensions for Stereolithography

Ferroelectric photoactive suspensions for stereolithography have been developed by dispersing a high volume fraction of barium titanate powder in hexanediol diacrylate (HDDA) with the aid of effective photoinitiators and dispersants. Rheological properties showed a shear thinning behavior and a low viscosity at a shear rate adequate for the recoating process. The barium titanate–HDDA suspension showed poor curing behavior due to the large refractive index difference between the ceramic and the resin. The coarse barium titanate–HDDA suspension showed a smaller surface reflectance and a larger cure depth than the fine barium titanate–HDDA suspension.     

聚乙烯热收缩异型套管的研制

对聚乙烯热收缩异型套管的成型工艺进行了研究,考察了各种成型因素对制品的影响。发现注塑、辐射交联的热收缩异型套管加热后出现收缩变形、表面起皱等缺陷,达不到质量要求,而模压能得到尺寸与形状准确、外观质量良好的热收缩异型套管。     

钛酸锶钡结构与制备工艺研究进展

钛酸锶钡[(Ba,Sr)TiO3,SBT]是1种重要的电子陶瓷材料,具有高介电常数、低漏电流、高热释电系数,高的介电可调等特性,广泛用于动态随机存储器、热释电探测器、介质移相器等电子元件的制备。综述了钛酸锶钡[(Ba,Sr)TiO3,SBT]的结构和制备工艺研究进展,评述了制备工艺和掺杂等对钛酸锶钡的结构和性能的影响,并指出了钛酸锶钡尚待解决的问题。     

Effects of Excess Barium Ions on Aqueous Barium Titanate Tape Properties

The effects of excess free barium ions in aqueous barium titanate slip on the resulting BaTiO₃ tape properties were investigated in terms of the slip behavior, green/sintered tape density and morphology, and dielectric properties. The excess free barium ions expressed by means of the Ba/Ti ratio adversely affected most tape properties. Increase in the slip viscosity, green porosity, and agglomeration along with a decrease in mechanical properties and green/sintered density were found with the increase in the Ba/Ti ratio. However, dielectric permittivity was increased with increase in the Ba/Ti ratio. An effort was made to correlate these phenomena with Ba²⁺ leaching in water for realistic multilayer ceramic capacitor applications.     

Anomalous Grain Growth in Donor-Doped Barium Titanate with Excess Barium Oxide

Grain growth and semiconductivity of donor-doped BaTiO₃ceramics with an excess of BaO and additions of SiO₂or B₂O₃were studied. The microstructures and electrical measurements on sintered samples revealed that their electrical properties are related to the microstructure development of the sintered samples. Samples heated with an excess of BaO developed a normal microstructure during sintering, as a consequence of normal grain growth (NGG), and were yellow and insulating. In contrast, samples with an excess of BaO and an addition of SiO₂or B₂O₃exhibited anomalous grain growth (AGG) and were dark blue and semiconducting after sintering. When some BaTiO₃seed grains were embedded in a sample of donor-doped BaTiO₃with an excess of BaO (without SiO₂or B₂O₃), AGG was observed, i.e., some seed grains grew into large grains and were blue and semiconducting. An explanation is given for why AGG is responsible for the oxygen release and the formation of semiconducting grains in donor-doped BaTiO₃and not NGG.     

微波水热法合成Mn掺杂BaTiO_3纳米粉体

以Ti(OC_4H_9)_4 、Ba(NO_3)_2 和C_4H_6MnO_4·4H_2O为原料,采用微波水热法合成了Mn掺杂的BaTiO_3纳米粉体.通过X射线衍射(XRD)和扫描电子显微镜(SEM)对产物进行了表征.并研究了影响Mn掺杂BaTiO_3晶体生长和形貌的主要影响因素.实验结果表明:掺杂量为1.0%,反应时间为30 min,烘箱干燥温度为82 ℃,能制备出单一的粒径均匀的掺Mn的BaTiO_3纳米粉体,且粉体的粒径尺寸约为100 nm.     

Preparation of Highly Dispersed Ultrafine Barium Titanate Powder by Using Microbial-Derived Surfactant

To uniformly disperse ultrafine BaTiO₃ particles with a stoichiometric composition and several tens of nanometers in diameter to primary particles during the sol–gel synthesis process, a new aqueous surfactant with a high hydrophilic group density and special cis-structure was prepared from a microbial product and added to solution before the sol–gel synthesis reaction. Because of the rapid formation of large and porous aggregates which were 30–50 μm in diameter in suspension without addition of this unique structural surfactant, the prepared ultrafine BaTiO₃ particles caused rapid sedimentation in suspension. The addition of the surfactant in the range of 7.1 wt% for the synthesized BaTiO₃ particles made it possible to decrease the size of the aggregates in suspension as well as the sedimentation velocity while maintaining the stoichiometric composition. The optimum additive content to obtain the minimum aggregate size of about 100–200 nm in diameter and the highest dispersion stability in suspension while maintaining the stoichiometric composition of prepared ultrafine BaTiO₃ particles without other phases was determined at about 7.1 wt%. Because the excess addition of this surfactant at more than 8.5 wt% inhibited the uniform synthesis of BaTiO₃ particles, an amorphous phase with a highly specific surface area and a BaCO₃ phase formed in the synthesized particles.     

Laser-Sintered Barium Titanate

Laser sintering of alkoxy-derived ultrafine BaTiO₃ powders was investigated. The temperature increases of the sample with laser irradiation were measured with a thermocouple. It was found that laser irradiation could generate enough heat to sinter ceramics. A slurry was prepared by mixing an alkoxy-derived BaTiO₃ powder, binder additives, solvent, and plasticizer. The slurry was tape cast and dried to give a green sheet. The green sheet was laser sintered and was then characterized by SEM, XRD, and density measurements. The effect of burnout before laser irradiation and the characteristic microstructure of laser-sintered BaTiO₃ are described.     

XPS Analysis of Submicrometer Barium Titanate Powder

A commercial submicrometer BaTiO₃ powder was analyzed using X-ray photoelectron spectroscopy. The analysis revealed the powder surfaces to be covered with a layer of physisorbed H₂O and chemisorbed –OH ions. A BaCO₃ residual not detected with XPS was shown to be present in the powder using X-ray diffraction, suggesting that the carbonate takes the form of discrete particles rather than of a continuous surface layer. A relaxed surface phase detected in previous XPS analyses of bulk BaTiO₃ was also shown to be present. Depth profiling revealed the powder surfaces to be Ti-rich, confirming the presence of a phase, or phases, to stoichiometrically balance the barium carbonate.     

过渡金属掺杂BaTiO3的晶格结构和相变特性

采用溶胶一凝胶法制备纯净BaTiO3,将1．0mol％的Cr、Fe、Mn、Co掺杂BaTiO2和浓度分别为1．25mol％、1．5mol％、1．75mol％、2．0mol％的Fe掺杂BaTiO2前驱粉体,经热压烧结,并在1350℃下烧结成多晶陶瓷样品。对样品进行XRD和DSC表征的研究。分析了掺杂离子种类和浓度对样品的晶格四方性、相变温度（居里点）和相变潜热的影响。分析结果表明,掺杂BaTiO2的四方性、居里点和相变潜热低于纯净BaTiO。且随Cr、Fe、Mn、Co的掺杂顺序以及Fe掺杂浓度的增加而减少。过渡元素掺杂BaTiO2的居里点和相变潜热髓晶格四方性的降低逐渐减小。