Self-Healing Behavior of Blends Based on Ionomers with Ethylene/Vinyl Alcohol Copolymer or Epoxidized Natural Rubber Md. Arifur Rhaman, Maurizio Penco,* Gloria Spagnoli, Antonio Mattia Grande, Luca Di Landro Introduction The development of the ability of materials to maintain or restore their functionality even after degradation or damages is the basis for significant improvements of long term reliability and operation lifetime of structures. For example, health monitoring and damage tolerance con- cepts are extensively adopted and developed in advanced applications, as in aerospace field. In accordance to such concepts, damage is accepted, monitored or estimated, and accounted for in the design or maintenance programs. In a number of situations, however, including non-structural applications, presence of damage may remarkably impair the functionality or lifetime of the component, so that it is hardly tolerable. Such situations include, for example, space suits and space living ambient, liquid propellant container, inflatable objects, food packaging, where gas or liquid tightness is a crucial characteristic; and also protective coatings, optical surfaces, conductive or resistive materials, where continuity and thickness constancy are stringent requirements. In all such situations, the availability of materials capable of easy and quick repairing is greatly valued. Self-healing is a biomimetic concept, which has sug- gested the idea of damage management principle in Full Paper Md. A. Rhaman, M. Penco, G. Spagnoli Dipartimento di Ingegneria Meccanica e Industriale, Universita ` di Brescia, Via Valotti 9, 25123 Brescia, Italy E-mail: maurizio.penco@ing.unibs.it A. M. Grande, L. Di Landro Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano, via La Masa 34, 20156 Milano, Italy The effect of blending on the self-healing behavior of an ethylene/methacrylic acid copolymer ionomer is investigated. Binary EMNa/EVA and EMNa/ENR blends are studied by ballistic puncture tests. In the composition range explored (15–50 wt% of EVA and ENR), the self- healing characteristics decrease with increas- ing amount of EVA but are maintained in the whole range for EMNa/ENR blends. The bullet impact zones were observed using OM. Tensile tests showed that the blending process gives the opportunity to tune the mechanical characteristics without significant loss in the self-healing properties, particularly in EMNa/ENR blends. Component compatibility, blend morphology and thermal properties were studied using DSC, SEM, and DMTA. Molecular interactions between the phases in the blends are discussed. Macromol. Mater. Eng. 2011, 296, 1119–1127 ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com DOI: 10.1002/mame.201100056 1119