Core-Shell Structured Carbonyl Iron With Polystyrene Foam Microparticles Designed for Enhanced Sedimentation Stability and Its Magnetorheology

Magnetorheological fluid;Carbonyl Iron;Polystyrene foam;Core-Shell structure;Supercritical Carbon Dioxide fluid.;620

공과대학 재료공학부 ;

University:서울대학교 대학원

关键词: Magnetorheological fluid;    Carbonyl Iron;    Polystyrene foam;    Core-Shell structure;    Supercritical Carbon Dioxide fluid.;    620;   

Others  :  http://s-space.snu.ac.kr/bitstream/10371/123339/1/000000025054.pdf

美国|英语

来源: Seoul National University Open Repository

【 摘 要 】

The sedimentation stability of carbonyl iron (CI)-based magnetorheological (MR) fluids was enhanced by applying a dual-step processing comprising coating a PS layer on the CI particles surfaces via conventional dispersion polymerization, subsequently by the foaming of the PS coating layer using the supercritical carbon dioxide fluid foaming processing to produce a core-shell structured CI coated with Polystyrene foam (CI/PSF) particle. The reduction of density after coating and foaming modification was verified using a pycnometer and the surface morphologies were observed by SEM. The specific surface areas were determined by Brunauer–Emmett–Teller (BET) adsorption measurements to study the change in surface roughness upon modification. The elemental analysis was done to confirm the foaming processing did not contaminate the product. The influence of the volume expansion after modification on the magnetic properties was investigated by analyzing the MR performance using a vibrating sample magnetometer and rotational rheometer. Finally, the sedimentation properties of the synthesized particles was examined using Turbiscan apparatus. MR fluids containing the newly developed CI coated with Polystyrene foam (CI/PSF) particles exhibited remarkable stability against sedimentation essentially attributed to the reduced mismatch in density between particles and the carrier medium.