Effects of Polyelectrolyte as a Dispersant on Slip Casting of Ceramic Slurries

聚电解质作为分散剂对陶瓷浆料注浆成型的影响

基本信息

批准号：
07651016
负责人：
HASHIBA Minoru
金额：
$ 1.28万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

It is desirable in slip casting to prepare concentrated slurries whilst retaining fluidity. A polyelectrolyte as a dispersant is effective for thickening of the slurries and that polymer have a characteristic function in fluidizing slurries, other than that dispersion and stabilization. The flow point refers to the least amount of a medium (the thickening limit) required for a definite amount of powder of a start to flow. The fluidity of the slurries in the vicinity of the thickening limit was affected by a kind of dispersant, the concentration and molecular weight of dispersants and the solid loading in the slurries. The dispersion accompanied by fluidization and the limit of thickening should be related to the structure of the length extension of dispersant (the conformation of dispersant) in the adsorption layr on the ceramic particles and also to the interaction among such solid particles in the concentrated slurry. A polyelectrolyte dispersant has electrostatic effect and an addit … More ional steric effect since the polymer expands in the adsorption layr thereby exceeding the effective distance that the van der Waals attraction force operates over.An average shell volume occupied in the adsorption layr on alumina by a polyacrylic acid ammonium salts molecule (PAA) defined as the average area occupied by an adsorped PAA on alumina multiplied by the average thickness of the water layr at the limit of thickening, has been calculated from the adsorbed amount of PAA and from the flow points of alumina in the presence of PAA of different molecular weights. A steric effect of the PAA dispersant on the dispersion of alumina resulted in a flow with no yield stress. This was due to the change of the extension of PAA in the adsorption shell from a sphere to an ellopsoid with a long axis which exceeded the effective distance that the van der Waals attraction force reaches at a molecular weight for the PAA of between 10,000-20,000.It was also developed the determination method of polyelectrolyte and discussed the effects of pH changes on the conformation changes for polymers in the slurries, the adsorbed amount of polymers and the dispersion accompanied by fluidization in the presence of dispersant. Less

在滑动铸造中，需要准备浓缩的浆液，同时保持流动性。聚电解质作为分散剂可有效地增厚浆液，并且除了分散和稳定外，聚合物在流化的浆液中具有特征性的功能。流动点是指定义数量的开始流量粉末所需的介质最少（增厚极限）。 The fluidity of the slurries in the vicinity of the thickening limit was A polyelectrolyte dispersant has electrostatic effect and an addit … More ional steric effect since the polymer expands in the addorption layr thereby exceeding the effective distance that the van der Waals attraction force operates over.An average shell volume occupied in the addorption layr on alumina by a polyacrylic acid ammonium salts molecule (PAA) defined as在氧化铝上吸附的PAA所占据的平均面积乘以增厚极限的水的平均厚度，在存在不同分子量的PAA的情况下是根据PAA的吸附量和氧化铝的流动点计算得出的。 PAA分散剂对氧化铝分散体的空间作用导致流量没有屈服应力。这是由于增加的壳壳中PAA的延伸从球体变为长轴，其长轴超过了范德华的吸引力在10,000-20,000之间的分子量下达到的有效距离。聚合物和在存在分散剂存在下通过流化而实现的分散体。较少的