Measurement of Van der Waals Force Between Polyethylene Particles Based on Atomic Force Microscope
Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
Abstract：Particle agglomeration is a severe technical problem for the stable operation of fluidized bed reactors of polyolefin. In this study, taking high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) particles as the research objects, the atomic force microscopy (AFM) coupled with colloidal probe was applied to measure the van der Waals forces between PE particles, which were compared with the calculated results. Under the experimental conditions, the measured van der Waals forces between HDPE particles or LLDPE particles were both in the range of 9.7 to 17.77 nN. This meant they were in the same order of magnitude, but the specific values were slightly different. The experimental results also showed that the van der Waals force was closely related to the surface roughness and particle size, but the effect of former one was more important. Furthermore, a model was established based on the fitted Hamaker constant, the calculated changing trend of van der Waals forces with the particle distance was in good agreement with the experimental results. Results in this work can provide basic data and guidance for the control of particle agglomeration in fluidized bed reactors for polyethylene.
HUANG Zhengliang,Hong Ying,TIAN Sihang et al. Measurement of Van der Waals Force Between Polyethylene Particles Based on Atomic Force Microscope[J]. 化学反应工程与工艺, 2020, 36(4): 319-324.
