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采用经典的溶胶-凝胶(Sol-gel)法合成直径50 nm的二氧化硅(SiO2)粒子,通过“两相”模型对不同粒子体积分数(φ)的二氧化硅/聚苯乙烯(SiO2/PS)悬浮体系动态粘弹行为进行拟合,讨论温度与φ对频率依赖性动态流变的影响。研究发现,应变放大因子Af和“粒子相”特征模量Rf″(φ)均随φ增加而增大;Af几乎无温度依赖性,Rf″(φ)随温度升高而降低。该现象归因于温度升高加速了由扩散控制的SiO2团聚过程,导致纳米粒子比表面积减小,抑制了粒子网络的形成。研究表明,两相模型可很好地应用于SiO2/PS悬浮体系的动态流变行为。
Silica (SiO 2) particles with a diameter of 50 nm were synthesized by a classical sol-gel method. The silica / polystyrene with different particle volume fraction (φ) (SiO2 / PS) suspension system to investigate the effect of temperature and φ on the frequency-dependent dynamic rheology. The results show that both the strain amplification factor Af and the characteristic particle size Rf “(φ) increase with the increase of φ. Af have almost no temperature dependence and Rf” (φ) decreases with increasing temperature. This phenomenon is attributed to the temperature increase accelerating the diffusion-controlled SiO2 agglomeration process, resulting in the reduction of nanoparticle specific surface area and the formation of particle networks. The results show that the two-phase model can be applied well to the dynamic rheological behavior of SiO2 / PS suspension system.