Improvement of the Sphericity and the Thickness Uniformity of the Polystyrene (PS) Shell Microsphere during Curing Process

• Main Authors: Xiaotian Han, Hua Zhou, Yifei Zhu, Liangyu Wu, Feng Yao, Cheng Yu
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Coatings
• Subjects: microencapulation; polystyrene microsphere; compound droplets; external flow fields; curing process
• Online Access: https://www.mdpi.com/2079-6412/9/6/385

To improve the quality of dispersed polystyrene (PS) compound droplets, a new random rotating curing system is designed. In addition, the qualities of the curing products of the PS compound droplets of this new system are compared with those of the traditional curing system with a constant rotating speed, so as to verify the effectiveness of the new system on the quality improvement of the PS compound droplets. The effect of the liquid level, rotation rate and the density difference on the curing process is also analyzed to reveal the mechanism of the curing process in a rotating flow field. The results indicate that, in the new rotating curing system, the disturbance of the fluid increases the deformation recovery ability of the compound droplets. Furthermore, the vortex with different directions in the external flow fields, make the compound droplets spin in many directions, which improves the spheroidization and concentricity of the compound droplets. Compared with using the traditional rotating curing system, when utilizing the random rotating curing system, the sensitivity of the microspheres’ quality to the density mismatch between the phases is smaller, and the sphericity and the thickness uniformity of the polystyrene (PS) microsphere increase by 10.2% and 4.5%, respectively. In addition, there is an optimal rotation rate for the random rotating curing device, which can optimize the survival rate and quality of the hollow microspheres.