汽车工业生产用热熔胶膜的研制

介绍了汽车工业生产内装饰复合材料用热熔胶膜的性能及其研制状况。这种热熔胶膜具有使用便捷,高效,生产、使用过程中没有污染的具有热熔胶膜的特长。     

马来酸酐接枝聚丙烯的进展

马来酸酐接枝聚丙烯是拓宽聚丙烯应用领域的重要手段之一,本文综述了马来酸酐接枝聚丙烯的接枝方法和原理,接枝物的性能以及接枝物在聚丙烯合金和共混物、复合材料、粘合剂和涂料领域的广泛应用。     

电子陶瓷和器件的低温共烧技术

较系统地介绍了电子器件用低温共烧陶瓷(low temperature cofired ceramics,LTCCs)材料,探讨了其工艺中的若干问题。电子器件用低温共烧陶瓷材料包括:玻璃/陶瓷复合材料、结晶化玻璃、晶化玻璃/陶瓷复合材料以及液相烧结陶瓷,其中典型的和最为常用的LTCCs为玻璃/陶瓷(特别是氧化铝)复合材料。正在研究的一些陶瓷介质材料中,Bi基介质材料引起了人们的关注。玻璃/陶瓷复合材料的制备工艺中,应当着重关注和加深了解玻璃的流动性和结晶性、玻璃的起泡、玻璃和陶瓷颗粒间的反应、共烧材料的匹配等问题,从优选材料配方和优化工艺着手,从而获得优质可靠的材质和器件。     

纳米稀土复合固体超强酸催化合成乙酸苄酯

采用共沉淀法制备了纳米稀土复合固体超强酸SO4^2-／ZrO2-2％Nd2O3催化剂，电镜分析表明，催化剂颗粒直径在25nm左右，比表面积测定：71．03m^2／g。酸强度-12．70〈Ho〈-11．99。并对合成乙酸苄酯的最佳反应条件进行了研究。研究表明：当苯甲醇与乙酸的物质的量比为1：2，反应时间为5h，反应温度为120℃，催化剂用量为6％苯甲醇的质量时，酯化率可达92．04％。研究发现，该催化剂可重复使用并可活化再生。     

有侧移半刚性连接组合框架柱的稳定分析

为了研究有侧移半刚性连接组合框架的稳定性能,利用三柱子框架模型,考虑了梁端和柱远端不同约束情况对柱有效长度系数的影响,提出柱有效长度系数的简化方法.通过算例研究了节点的非线性弯矩-转角关系和荷载水平大小对柱有效长度系数的影响,比较了简化方法、Barakat-Chen方法与精确方法的计算结果.研究表明:简化方法比Barakat-Chen方法有更好的精确度,与精确方法计算结果接近.     

一种多元复合地基复合模量的计算方法

多元复合地基的沉降计算依赖于其复合模量的取值.目前多元复合地基复合模量计算均未考虑桩对桩间土的侧向挤密作用,因而其沉降计算结果与实际值相差较大.而考虑桩体与桩间土的侧向挤压作用,依据线弹性变形理论,推求的多元复合地基的复合模量公式应用于工程实例,结果表明,该方法是合理可行的,并且存在着参数易于确定、方法简便、机理清楚的特点.     

Research on the friction and wear mechanism of Poly(vinyl alcohol)/hydroxylapatite composite hydrogel

Poly(vinyl alcohol)/Hydroxylapatite (PVA/HA) composite hydrogel was prepared with poly(vinyl alcohol) and hydroxylapatite as raw materials, using the method of repeated freezing and thawing. The morphologies of PVA/HA composite hydrogel were observed by means of high-accuracy 3D profiler and scanning electron microscope (SEM). The compressive elastic modulus and the stress relaxation characteristics of PVA/HA composite hydrogel were measured using the flat-head cylinder indenter. The friction and wear tests between PVA/HA composite hydrogel and bovine knee articular cartilage were performed on the micro-tribometer. The worn morphologies of PVA/HA composite hydrogel were observed with environmental scanning electron microscope (ESEM). The results showed that PVA/HA composite hydrogel has the cross-link network microstructure which is similar to that of the natural bovine knee articular cartilages. With the increase of freezing-thawing cycles and the HA content, the degree of cross-link and the crystallization of PVA/HA composite hydrogel both increase, the elastic modulus increases evidently, the rate of stress relaxation is improved and the value of balance stress decreases. The friction coefficient decreases with the increase of the freezing-thawing cycles and the HA content. The more the freezing-thawing cycles are, the earlier the friction coefficient reaches the stable balance value. The friction deformation depth between PVA/HA composite hydrogel and bovine knee articular cartilage is inversely proportional to freezing-thawing cycles and the HA content. The main wear mechanisms of PVA/HA composite hydrogel are plastic flowing and adhesive flaking. The wear severity degree decreases with the increase of freezing-thawing cycles and the HA content. Supported by Key Program of the National Natural Science Foundation of China (Grant No. 50535050), Program for New Century Excellent Talents in University (Grant No. NCET-06-0479) and Natural Science Foundation of Jiangsu Province (Grant No. BK2005403)     

无机纳米-聚酰亚胺复合薄膜介电性研究

测试了纳米Al2O3-聚酰亚胺(PI)复合薄膜和纳米SiO2-聚酰亚胺复合薄膜的介电常数、介质损耗角正切和电导电流特性.结果表明,随着无机物含量的增加,两种复合薄膜的相对介电常数和介质损耗角正切增大,电老化阈值减小;无机物含量相同时,Al2O3-聚酰亚胺复合薄膜的相对介电常数和介质损耗角正切比SiO2-聚酰亚胺复合薄膜大,电导电流大,电老化阈值小.     

聚丙烯/弹性体复合材料的性能研究

通过共混改性的方法制备了PP/EPDM复合材料。然后对复合材料的性能进行分析,研究了EPDM的含量对复合材料的拉伸强度、冲击强度、维卡软化温度以及流动性等方面的影响规律,并对此影响规律进行合理的解释。     

Milled fibre reinforced epoxy resin — an engineering polymer composite

A milled fibre reinforced epoxy resin composite (MFRE) has been developed for low temperature use. It is resistant to fracture at temperatures down to at least 77 K in direct contact with liquefied gases. It can be used as an adhesive, a gap-filling mastic or a moulding compound for difficult cryogenic applications. The characteristics of the material and some applications are described.