Investigation of Membrane Emulsification for the Scaled Production of Microcapsules for Self-sealing Cementitious Systems

¹ Department of Engineering, University of Cambridge, Trumpington Road, Cambridge CB2 1PZ, UK
² Micropore Technologies, Wilton Centre, Redcar, TS10 4RF, UK

^* Corresponding author: crr41@cam.ac.uk

Abstract

Capsule-based self-sealing in cementitious systems is an advantageous methodology which has the potential to decrease water ingress and thus enhance a system’s durability and extend its lifespan. If capsule-based self-sealing is to be considered as an industrial solution, production must be scaled while capsule quality and batch reproducibility are maintained. In this study, polyurethane-shelled microcapsules containing a commercially available water repellent agent were produced using membrane emulsification equipment, supplied by Micropore Technologies, followed by interfacial polymerisation. Production was scaled across three different cross-flow membrane emulsification devices, the AXF-1, the AXF-3, and the AXF-4, increasing production output to a maximum of 850 L/hr of capsule suspension. Following production, capsules were characterised, measuring average size and size distribution, as well as integrated into a cementitious matrix. The results highlight the key parameters that govern capsule size, the versatility of the equipment, and the consistent quality of capsules produced. It is hoped that this scaled production of capsules will help to develop the commercial viability of capsule-based self-sealing cementitious systems.