【摘要】 用光子相关光谱测定了苯乙烯-二乙烯基苯(St-DVB)共聚超微粒在良溶剂(甲苯)与θ溶剂(环己烷)中不同温度下的分子扩散系数,与流体力学方程结合给出了该微粒在无限稀时的等效流体力学半径。微粒分子扩散与温度的关系符合Arrhenius方程。不同温度的测试结果表明,St-DVB共聚超微粒的微交联网络结构使其分子形态不易改变。在θ溶剂中,T<θ时,微粒发生聚集,表现出大分子的协同扩散;T>θ时,在较高浓度,扩散系数偏离与浓度的线性关系。流体力学作用和热运动决定了微粒分子的扩散行为。更多还原

【Abstract】 The molecular diffusion coefficients of styrene-divinylbenzene ultrafine particles were measured by photon correlation spectroscopy in good (toluene) and θ(cyclohexane) solvents at various temperatures. The hydrodynamic radius and activation energy for diffusion were calculated. The experimental results show that the molecular morphology of St-DVB ultrafine particles changes hardly because of its crosslinking structure. In 0 solvent,when T<θ, the particles aggregated and behaved as macromolecular cooperative diffusion; when T>θ, the diffusion coefficient was deviated from the linear relationship between D and C in high concentrations. The functions of hydrodynamics and thermodynamics controlled the diffusion behavior of the ultrafine particles.更多还原