白水泥基无机胶黏剂的制备及机理研究

Preparation and Adhesive Mechanism of White Cement-Based Adhesives

以白水泥为基体,添加一定量的减水剂、速凝剂、增稠剂及聚乙烯醇聚合物等外加剂制备一种新型环保型胶粘剂,研究外加剂用量对白水泥基胶粘剂的胶原强度的影响规律。通过扫描电镜(SEM)、差示扫描量热(DSC)和红外光谱(FTIR)等手段分别对改性前后白水泥基体的微观形貌、热学性能及官能团的变化进行分析,从而研究其粘接机理。结果表明,减水剂、速凝剂、增稠剂及聚乙烯醇聚合物的添加量分别为2%,0.6%,2%,8%时,在室温下养护3d后的白水泥基体的胶原强度由0.08MPa增大为1.3MPa,较纯白水泥基体提高15倍。机理分析表明,在水化过程中,外加剂与白水泥基体之间无化学键合作用,有机聚合物颗粒逐渐聚集形成连续薄膜,将水化产物粘接在一起,形成一个完整的网状结构,从而提高白水泥基胶粘剂的胶原强度。

A new environmental friendly adhesive was prepared from white cement modified by water reducer, accelerator, thickener, polyvinyl alcohol polymer, etc. The main objective of this paper was to investigate the effect of the dosage of organic modifiers on the adhesive strength. The morphologies of the matrix of white cement were investigated by scanning electron microscope (SEM). Effects of modifiers on thermal properties and functional groups of white cement were studied by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), and then adhesive mechanism was studied. The results indicate that the adhesive strength of modified cement is up to 1.3 MPa from 0.08 MPa after curing for 3d at room temperature when the dosage of water reducer, accelerator, thickener and polyvinyl alcohol polymer are 2%, 0.6%, 2%, and 8% respectively, which is 15 times than that of unmodified white cement. The mechanism analysis shows that there is no chemical bonding reaction in the hydration process and organic polymer particles are gradually gathered into a continuous thin film; meanwhile the hydration product are bonded together to form a complete network structure, so the collagen strength of the white cement-based adhesives is improved significantly.