EFFECT OF PROCESSING PARAMETERS ON THE MORPHOLOGY OF MICROCAPSULES PREPARED FOR SELF-HEALING APPLICATIONS

ROMINA OLLIER; EXEQUIEL S. RODRIGUEZ; VERA A. ALVAREZ

Bahía Blanca

Simposio; IX Simposio Argentino de Polímeros; 2011

Universidad Nacional del Sur

Microcracking is a critical problem for polymers and polymer composites during their service in structural applications. Development and propagation of microcracks can eventually lead to catastrophic failure of the material, deteriorating its performance and reducing its lifetime. The ability of self-healing materials to repair cracks is necessary to retain structural integrity. Based on biological systems, self-healing materials are being developed to improve the lifetime of materials used in various applications including coatings and structural components (Yuan at al., 2009). Many strategies have been investigated in the development of self-healing materials (Rule et al., 2007). One of the most successful and versatile approach consists on dispersing capsules containing a healing agent and a solid catalyst within a polymer matrix. When a crack propagates through the material, it ruptures the embedded microcapsules releasing the healing agent into the damaged area, which reacts with the catalyst that has been dispersed in the material. The catalyst causes polymerization of the healing agent, repairing the crack (Yuan et al., 2008). Brown et al. (2003) developed an interesting encapsulation method based on in situ polymerization of urea-formaldehyde (PUF) microcapsules encapsulating dicyclopentadiene (DCPD) healing agent. When a crack ruptures a microcapsule, DCPD is released and is polymerized by Grubbs’ catalyst through ring-opening metathesis polymerization. Microcapsules diameter and surface morphology significantly influence capsule rupture behavior and healing agent release in self-healing polymers. So selecting appropriate process parameters is very important for controlling the properties of microcapsules and improving the healing efficiency. The aim of this work was to synthesize PUF capsules containing DCPD and to analyze the effect of the rate of agitation and the concentration of DCPD on the microcapsules’ quality, size distribution and surface morphology.