Role of Phase Morphology on the Damage Initiated Self‐healing Behavior of Ionomer Blends

Abstract

The development of self‐healing materials, based on polymer blends, is an important issue either from a scientific or a technological point of view. The application of such materials can be remarkably extended if healing effects can be maintained even in polymers that are modified in order to tune their physical and mechanical behavior. In this research the self‐healing behavior of blends made of ionomers (sodium and zinc salts of poly(ethyelene‐co‐methacrylic acid)—EMNa and EMZn) with functionalized elastomers (epoxidized natural rubber with different epoxidation levels—ENR50 and ENR25, polyisoprene—PISP) of different compositions is investigated. The role of processing conditions, phase morphology, functionalization level, polymers compatibility over self‐healing response are discussed. Rubber functionality and phase dispersion are recognized as crucial factors affecting the healing efficiency of blends. Results of ballistic tests, DSC thermal analysis, FTIR spectroscopy, optical and electron (SEM and TEM) microscopy observations, rheological and mechanical tests are presented as supporting evidences.

Intrinsic Self-Healing Polymers Based on Supramolecular Interactions: State of the Art and Future Directions

“…They can also be located in the side chains or act as end groups [141]. The most common pendant ionic group for selfhealing applications is a carboxylate group neutralized with sodium or zinc ions [142][143][144][145]. Unsaturated monomers containing carboxylate groups can be polymerized via radical polymerization techniques.…”

“…The properties of the ionomers depend on their material structure, which is strongly influenced by the utilized ion pairs, the ion content (neutralization level), and the elastic behavior of the main chain [148,153,155]. Thermoplastic EMAA copolymers (Scheme 1) have been widely investigated for self-healing under ballistic impact [144,145,[156][157][158][159]. Commercially available nonionic copolymers (Nucrel ® ) (http://www.dupont.com/products-and-services/plas tics-polymers-resins/ethylene-copolymers/brands/nucrel-ethylene-acrylic-acid.html) and ionomers (Surlyn ® ) [26,160] have mainly been investigated.…”

Integrated solutions for safe fuel tanks

“…Thermoplastic materials, such as ionomers based on ethylene-co-methacrylic acid copolymers, partially neutralized with sodium or zinc, have shown self-healing behaviour after ballistic impacts [9][10][11][12][13][14]. Blends of ionomers with different polymers were also investigated: blending allows to get mechanical properties tuned over a wide range, yet maintaining self-mending ability [15][16][17]. However, certain conditions in terms of proper temperature range, bullet speed and shape are necessary for the autonomic healing to occur.…”

Improved solutions for dangerous liquid containment

“…Thermoplastic materials, such as ionomers based on ethylene-co-methacrylic acid copolymers, partially neutralized with sodium or zinc, have shown self-healing behaviour after ballistic impacts [3][4][5][6][7][8][9]. Blends of ionomer with different polymers, yet with selfmending ability, were also investigated [10][11][12][13][14]. However, certain conditions in terms of proper temperature range, bullet speed and shape are necessary for the autonomic healing to occur.…”