白炭黑、B4C改性酚醛树脂粘接石墨高温性能研究

在B4C改性酚醛树脂（phenol-formaldehyde resin,PF)高温粘接剂的基础上,向其中添加白炭黑（超细SiO2)制备新型粘接剂,并对石墨材料进行粘接和热处理,测试了不同温度热处理后的粘接强度。结果表明,2550℃处理后新型粘接剂仍具有理想的耐热温度和粘接强度。利用扫描电镜（SEM）对样品断面形貌进行观察,研究了粘接界面的组成和结构变化及其与粘接性能之间的关系。实验结果表明,白炭黑的添加,对提高胶层的致密性和粘接强度具有明显的效果。     

炭材料的性质与炭-炭粘接性能关系的研究

为实现高温条件下炭材料的有效连接，利用陶瓷组元改性酚醛树脂制备了树脂基高温粘接剂，用该粘接剂粘接了4种不同孔隙结构的炭材料，并进行400～1200℃的高温热处理，利用万能材料试验机考察了上述粘接剂的高温粘接性能，通过压汞仪分析了4种炭材料的孔隙结构及其与粘接性能间的相互关系，结果表明：粘接样品在高温热处理后仍具有较为理想的连接强度；炭材料表面的孔隙率和孔径分布对粘接强度有一定的影响；合适的孔隙率和孔径分布是实现高性能连接的必要条件。     

淀粉改性的研究进展

淀粉作为可再生的绿色生物材料具有巨大的潜在利用价值,但原淀粉本身的不足限制了其推广应用。为了提高淀粉的性能,需要对其进行改性处理。近年来,关于淀粉改性的研究报道引起了广泛关注,淀粉被赋予越来越多的功能特性。淀粉改性后,粘接力、冻融稳定性能、吸水以及热稳定性明显提高,广泛应用于胶粘剂、食品、污水处理以及生物医药等工业生产领域。概述了目前淀粉改性研究中的多种手段,主要包括化学改性(氧化、交联、接枝共聚、酯化、醚化和复合改性)、物理改性(热液处理、微波处理、电离放射线处理、超声波处理、球磨处理和挤压处理)、酶改性三大类,并综述了其研究进展及应用,最后对改性淀粉的研究现状以及改性方向进行了分析与展望。     

B_4C在石墨高温粘接过程中的组成和结构变化及改性机理

以酚醛树脂 (Phenol- form aldehyde resin,PF)和 B4C为原料制备的高温粘接剂 ,对石墨材料进行粘接 ,并在 2 0 0℃、80 0℃和 15 0 0℃进行热处理。对粘接样品的强度测试结果表明 ,粘接部件具有较高的耐热温度和粘接强度。利用扫描电镜 (SEM)和 X射线衍射 (XRD)对不同温度热处理后的粘接界面结构形貌及粘接剂组成进行了分析 ,研究了酚醛树脂中的 B4C添加剂在粘接过程中的结构变化及其对提高粘接性能的作用机理。     

粘接剂对直接粘贴芯片表面残余应力的影响

封装所导致的残余应力是电子器件封装和组装重点关注的问题。利用硅压阻传感器，原位实时地记录了不同粘接剂在FR4有机层压板衬底上固化过程中芯片表面的应力变化和残余应力的分布状况，研究表明，使用热膨胀系数较小的有机粘接剂粘贴芯片时，可获得较低的残余应力和相对优越的应力分布。该方法可作为芯片直接粘接时选择有机粘接剂的参照。     

包装复合膜用松香改性水性聚氨酯胶粘剂

利用松香改性水性聚氨酯胶粘剂,研究了二羟甲基丙酸(DMPA)用量、NCO/OH值、松香用量对乳液性能的影响,比较了改性前后该胶粘荆对多种塑料薄膜的粘接性能.实验结果表明改性后的胶粘剂对多种塑料薄膜具有较强的粘接能力.     

淀粉胶粘剂的改性研究

淀粉胶粘剂应用历史久远,由于纯淀粉胶粘剂具有粘接强度低、耐湿性差和干燥速率慢等缺点,作为天然高分子的淀粉的改性成为近年来的研究热点.本文从氧化、醚化、酯化、交联和接枝共聚等方面综述了近年来淀粉胶粘剂的研究现状,对淀粉胶粘剂的未来发展提出了看法.     

基于淀粉直接改性的热塑性淀粉塑料研究进展

综述了近年来淀粉经改性后用于热塑性淀粉塑料领域的研究进展。根据淀粉的改性方法不同,主要综述了淀粉氧化改性、酯化改性、醚化改性、交联改性以及聚氨酯改性后对所制备的热塑性淀粉塑料性能的影响,归纳和总结了最新的研究成果并提出展望。     

摩擦材料用有机粘接剂的研究与进展

有机粘接剂是摩擦材料中最关键的基体组分,它将各种成分紧密地粘合在一起以获得所需性能,其性能好坏直接影响摩擦材料性能的发挥,尤其是其耐温性决定着摩擦材料的使用性能。文中综述了近年来摩擦材料用有机粘接剂的研究与进展,重点介绍了酚醛树脂(PF)粘接剂的改性研究概况,希望为高性能摩擦材料用粘接剂的研制提供一些资料积累和思路。     

大口径反射镜侧支撑结构力学分析

从理论上论述了在真空望远镜主反射镜的几种侧支撑结构,并运用有限元法对之分别进行了分析计算,得到使用了不同侧支撑结构的真空望远镜主镜在不同观测角度时的表面变形结果,通过比较变形结果,得到使用新配方粘接剂的粘接侧支撑机构支撑效果更好.在已确定使用Grubb十八点底支撑结构后,分析了使用粘接剂的侧支撑结构主反射镜变形与应力情况.通过有限元分析结果,得出变形结果符合整个光学系统的公差要求,同时证明了使用改性粘接剂的侧支撑系统可有效减少光学件表面变形量.     

Study on Heat Hardening Mechanism of Starch Composite Binder for Sand Mold (Core) by IR Spectra

The heat hardening mechanism of starch composite binder for sand mold (core) was studied by way of IR spectra. It is thought that the bonding strength of molding sand is mainly depended on the strength of the adhesive membrane itself. During heating the binder at certain temperature between 160 similar to 200 degreesC for one hour, a special composite structure is formed because of the interactions between different components, thus, it has higher low-temperature drying strength, better humidity resistance and higher high-temperature strength.     

Effect of Binder Composition on the Shrinkage of Chemically Bonded Sand Cores

Modern foundries increasingly use chemically bonded no-bake sand cores and molds because they provide ease of molding, good surface finish, and collapsibility. One of the most popular binder systems is alkyd oil urethane no-bake system comprising three parts: alkyd resin, catalyst, and crosslinking agent. Their amounts and ratios can influence mold shrinkage, and thereby dimensional quality of the resulting casting. With rising emphasis on net-shape casting, there is a need to optimize the binder composition to minimize dimensional errors, while achieving the desired bench life, stripping time and hardness. This work investigates the effect of binder composition on the dimensions of chemically bonded sand cores with respect to time. The maximum shrinkage of 0.15% over length was observed when resin content was 2.4% by weight of sand. The rate of shrinkage increased with the amount of catalyst. Measurement of core hardness and reduction in weight, followed by SEM studies, provided a better understanding of the underlying phenomena, especially formation of resin bridges between compacted sand particles and evaporation of solvent. This work is expected to aid in selection of the most appropriate binder composition for a given set of molding process constraints and cast product requirements.     

Properties of particleboard made from rubberwood using modified starch as binder

The objective of the study was to evaluate physical and mechanical properties of experimental particleboard panels made from rubberwood (Hevea brasiliensis) using modified starch as binder. Panels were manufactured using 15% corn starch modified with glutardialdehyde and tested for their properties based on Japanese Standard. The modulus of rupture and the internal bond strength of the panels met the requirement of the specified standard. Based on the findings in this work modified corn starch can have a potential to be used as binder to produce particleboard panels with acceptable properties.     

硅烷偶联剂对铸造用碱酚醛树脂黏结强度的影响

通过黏结强度的测定和SEM分析,研究了硅烷偶联剂对碱酚醛树脂性能的影响.试验结果表明,硅烷偶联剂可以改善黏结剂与砂粒表面的接触状态,极大地提高碱酚醛树脂砂的黏结强度.     

改性磷酸盐无机粘结剂的性能研究

目的探讨改性磷酸盐无机粘结剂在铸造生产中的性能。方法采用改性磷酸盐无机粘结剂配制自硬砂,分别测试自硬砂的抗拉强度、存放稳定性、可使用时间、发气性、溃散性等性能,并与水玻璃、呋喃树脂等传统粘结剂性能进行比较。结果通过生产实验验证,发现改性磷酸盐无机粘结剂能用于铸铁、铸钢及低熔点合金的铸造,其用于代替水玻璃应用于高温金属铸造,及代替有机树脂应用于有色合金铸造时,完全可克服砂型溃散性差的问题。结论改性磷酸盐无机粘结剂自硬砂性能优越。     

环保型铸造用无机树脂粘结剂研究进展与展望

综述了铸造用磷酸盐无机树脂研究现状及发展趋势,指出了研究使用无机树脂的必要性及其存在的主要问题和研究进展,展望了其应用前景.     

水玻璃砂粘结桥形貌的扫描电镜研究

本文介绍了普通水玻璃砂、ＣＯ２硬化改性砂和有机酯自硬砂的配比和残强──温度变化．在此基础上著助于扫描电镜观察了各种水玻璃砂在加热和冷却后砂粒间粘结桥的形貌．从而加深了解各种附加物（改性剂、溃散剂、硬化剂等）降低残强、提高溃散性的作用机理，促进水玻璃砂研究工作的开展．扫描电镜研究表明．为了改善水玻璃砂的溃散性．从粘结桥的形貌来说．重要的是：①减少砂粒间粘结桥的数量；②在加热后的粘结桥中做成大量的孔洞或微裂纹．破坏其连续性；③削弱粘结膜与砂粒间的附着强度；④形成难熔的化合物．改变粘结膜的组成和结构。在生产实践中应用经改性处理的水玻璃ＣＯ２硬化砂或有机酯自硬砂．均可以达到（或部分达到）上述目的．具有良好的溃散效果。     

The Granulation of a Hydrophobic Powder Using a Modified Starch

Granules have been prepared using a hydrophobic powder and a modified starch as binder. Granules suitable for tabletting couid De prepared using either water and 25% modified starch or a surfactant solution and not less than 5% modified starch. Compacts produced from a coarse size fraction of these granules disintegrated readily only if the granulation liquid contained surfactant. All compacts had adequate strength to withstand handling but those containing surfactant were weaker.     

An evaluation of starch obtained from pearl millet - Pennisetum typhoides. As a binder and disintegrant for compressed tablets

The binding and disintegrant properties of millet starch obtained from Pearl Millet - Pennisteum typhoides (Staph. Burn, and Hubb.) Fam. Gramineae have been evaluated using tablet formulations of four drugs.

The results showed that Millet starch compared favourably with Maize starch with regards to most of the parameters used to evaluate the tablets. It can be safely concluded that millet starch is suitable for use as a binder and disintegrant in tablet formulations.     

Adhesive Bonding and Self-Curing Characteristics of α-Starch Based Composite Binder for Green Sand Mould/Core

Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus,the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.