Microcapsule based self-healing thermosetting materials for structural applications

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

Advances in Materials Science Research, vol 16

Nova Publishers

Año: 2013; p. 121 - 148

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. A smart material is one for which a key material property is altered by controlling the response to an external stimulus. 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. Many strategies have been investigated in the development of self-healing materials. This chapter presents a comprehensive study of the main technologies being currently developed in the field of microcapsule based self-healing polymeric materials. First, it begins with a general examination of microencapsulation concept and techniques. Then, it continues with a detailed discussion of the basic self-healing requirements for the application of encapsulated healing agents in structural thermoset materials, mainly epoxy-based composites; the microencapsulation techniques that have been reported in literature, and the most important microcapsule based approaches, including a description of various types of healing agents, catalysts and/or hardeners. The parameters which affect the healing efficiency of the composite material such as wall thickness and roughness of microcapsules, diameter of microcapsules, healing agent loading and conditions are analyzed as well.