硅酸盐无机胶粘剂固化分形动力学

Fractal Kinetics of the Solidifying Reaction of Silicate Inorganic Adhesive

为了探讨硅酸盐无机胶粘剂的固化机理,通过硅酸盐无机胶粘剂固化过程中水份蒸发速率的测定,分析了其固化过程中的失水规律和动力学特征。结果表明硅酸盐无机胶粘剂固化过程的失水率随时间的变化规律可用方程x=Akt/[kt+10exp(-kt)]加以描述,且其固化过程是化学作用和物理作用共同作用的结果,但物理失水过程是控速步骤;胶粘剂预固化阶段遵循零级动力学规律,而后固化阶段表现为分形动力学特征,两阶段的表观活化能分别为11.882 kJ/mol和59.191 kJ/mol。引入分形理论中的DLA(Diffusion-Limited Aggregation)模型和DLCA(Diffusion-Limited Cluster Aggregation)模型,探讨了硅酸盐无机胶粘剂的粘接机理。

In order to research the mechanisms of solidification of silicate inorganic adhesive, the moisture evaporation law in solidification process of the adhesive and its solidification kinetics was investigated based on the experiment in which the dehydration rate in solidification process was determined. The results show that the change trend of dehydration rate in the whole process can be described with the following equation： x = Akt/[ kt ＋ lOexp （ - kt）], and physical action is in cooperation with chemical reactions in the whole solidification process of the adhesive, but physical reaction is the rate determining step; moreover, the kinetic characteristics of zero order reaction appears in the pre - solidification process of the silicate adhesive, and the fractional order reaction is found in the latter process. The apparent activation energy of the adhesion reaction is 11.882 kJ/mol and 59.191 kJ/mol on corresponding two steps respectively. The adhesion mechanism of the adhesive is also perfected with DLA model and DLCA model in fractal theory.