Exploring the Role of Supramolecular Associations in Mechanical Toughening of Interpenetrating Polymer Networks

Abstract

Model "supramolecular IPNs" were developed via the formation of a hydrogen-bonded, supramolecular network of 2-ureido-4-[1H]-pyrimidinone (UPy) telechelic poly(ethylene-co-1-butene) (SPEB) in the presence of photopolymerizable, hydroxyl-terminated polybutadiene (HTPB). The role of a supramolecular elastomeric phase in mechanical toughening of IPNs was explored through (1) dynamic dissociation and reassociation of the noncovalent, UPy supramolecular associations, and (2) interphase formation. While an ∼4× increase in tensile toughness of the HTPB matrix was observed through incorporation of 10 wt % ethylene−propylene rubber (EPR)as a conventional elastomeric toughening agentinto HTPB, it was shown that adding the same amount of supramolecular elastomer SPEB to HTPB led to ∼600× enhancement in tensile toughness. Strain rate-dependent mechanical response and fractography studies revealed that this dramatic toughness enhancement was due to dissociation/reassociation of the dynamic UPy linkages in the elastomeric phase that facilitated dilatational yielding of the IPN. This toughness enhancement was only observed in combination with the existence of strong interfacial coupling between the matrix and supramolecular phase as revealed by transmission electron microscopy and dynamic mechanical analysis. By exploiting noncovalent dynamics and interfacial control in interpenetrating networks, pathways are envisioned toward a new class of tough materials.

Graphene Nanoplatelet- and Hydroxyapatite-Doped Supramolecular Electrospun Fibers as Potential Materials for Tissue Engineering and Cell Culture

“…In the present study, we have employed the ureiodypyrimidone hydrogen bonding unit (UPy) as developed by Meijer and coworkers [45] because of its strong self-association, its synthetic accessibility, and the highly dynamic nature of low glass transition temperature (Tg) polymers comprising the UPy [45]. Most interestingly, UPy polymers have recently been shown to give unprecedented toughening in polybutadiene-based interpenetrating networks [46]. This type of SP was also recently incorporated into carbon fiber-reinforced plastics as interleaves, in order to play the self-healing agent role [47,48,49].…”

Mode II fracture toughening and healing of composites using supramolecular polymer interlayers

“…In this study, we have employed the ureiodypyrimidone hydrogen bonding unit (UPy) as developed by Sijbesma et al [25] because of its strong self-association, its synthetic accessibility, and the highly dynamic nature of low T g -polymers comprising the UPy [26]. Most interestingly, UPy-polymers have recently been shown to give unprecedented toughening in polybutadiene based interpenetrating networks [27]. In recent investigation, Zhang et al [28] discussed the state of our understanding about ionomers and the historical applications of these nanostructured polymers.…”

Computational Investigation of the Effect of Network Architecture on Mechanical Properties of Dynamically Cross‐Linked Polymer Materials

“…Soft polymer networks provide a versatile platform to engineer unique materials for a variety of applications such as optical communication devices, shape-memory materials, and biomedical systems. [1][2][3][4] Dynamic cross-linking of polymer networks [5][6][7][8][9] has attracted special interest in the past years since the use of dynamic linkages can result in extraordinary properties such as the two system types and present a framework to help study noncovalent and covalent cross-linkers within different types of polymer networks. We then perform mechanical tests with molecular dynamics (MD) simulations to obtain stress-strain curves for different configurations.…”

“…Soft polymer networks provide a versatile platform to engineer unique materials for a variety of applications such as optical communication devices, shape‐memory materials, and biomedical systems . Dynamic cross‐linking of polymer networks has attracted special interest in the past years since the use of dynamic linkages can result in extraordinary properties such as superior self‐healing, tensile and fatigue resistance, and toughness. Dynamic cross‐linkers usually belong to two different classes: noncovalent and covalent linkers.…”