Effect of miscible PMMA chain length on disordered morphologies in epoxy/PMMA-b-PnBA-b-PMMA blends by in situ simultaneous SAXS/DSC

Asada, Mitsunori; Oshita, Shinya; Morishita, Yoshihiro; Nakashima, Yasuhiko; Kunimitsu, Y.; Kishi, Hajime

doi:10.1016/j.polymer.2016.10.025

Cited by 21 publications

(13 citation statements)

References 29 publications

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“…The molecular weight of the acrylic BCPs and the composition (ratio of PnBA in the acrylic BCPs) were systematically controlled, as shown in Table 1. The PnBA block chain is immiscible and the PMMA block chain is miscible with the TPP catalyzed PN-cured DGEBA matrix polymer [37][38][39].…”

Section: Experimental Procedures 21 Materialsmentioning

confidence: 99%

“…In our previous publications [37][38][39], poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) (PMMA-b-PnBA-b-PMMA) triblock copolymers (acrylic BCPs) were blended with DGEBA using a wide range of curing agents. Among several cured blends, phenol novolac (PN)-cured DGEBA/acrylic BCP blends gave nanostructures.…”

mentioning

confidence: 99%

“…The miscibility between the PMMA blocks of the BCPs and the PN-cured DGEBA was a key factor in the formation of nanostructures in these blends [37,39]. Several nanostructures, such as spheres, cylinders (hexagonally-packed or randomly-dispersed), and curved lamellae were formed in the cured blends [37,38], which were controlled according to the molecular weight of the immiscible PnBA-block chain and the ratio of PnBA in the blends [38,39]. Small angle X-ray scattering analyses indicated that the seeds of the nanostructures were formed via a selfassembly mechanism rather than via reaction-induced phase separation [38].…”

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confidence: 99%

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Relationship between the mechanical properties of epoxy/PMMA-b-PnBA-b-PMMA block copolymer blends and their three-dimensional nanostructures

Kishi¹,

Kunimitsu²,

Nakashima³

et al. 2017

Express Polym. Lett.

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Epoxy thermosets are applied as structural materials and adhesives in many industries, such as aerospace, automotive, and electronics, due to their excellent mechanical properties and heat/solvent resistance. In the applications, polymer blends have been studied to toughen the epoxy thermosets [1-14]. Among various toughening modifiers, block copolymers (BCPs) consisting of chemically distinct block chains have attracted attention in order to give nanostructured epoxy blends [15-40]. After the finding of the nanostructured epoxy blends with amphiphilic BCPs [15, 16], many BCPs were synthesized to study the nanostructures and the mechanical properties of the cured blends. Dean et al. [21] reported that methylenedianiline-cured DGEBA/ poly(ethylene oxide)-b-poly(butadiene) (PEO-b-PB) block copolymer blends showed a phase transition from spherical micelles to branched cylindrical micelles and finally to vesicles, as the volume fraction of the epoxy-miscible PEO block decreased. Ritzenthaler and coworkers [23, 24] studied epoxy/ ABC triblock copolymer blends. Raspberry-like nanostructures were identified in polystyrene-bpolybutadiene-b-poly(methyl methacrylate

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Section: Experimental Procedures 21 Materialsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Relationship between the mechanical properties of epoxy/PMMA-b-PnBA-b-PMMA block copolymer blends and their three-dimensional nanostructures

Kishi¹,

Kunimitsu²,

Nakashima³

et al. 2017

Express Polym. Lett.

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“…spherical and cylindrical micelles, vesicles, and other (dis‐) continuous structures . Thereby, nanostructuring can occur in at least two ways and combinations thereof : (1) via a thermodynamically driven self‐assembling of the macromolecules prior to curing , and (2) a reaction induced phase separation mechanism (RIPS) during the curing process .…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Romeo et al clearly demonstrated an influence of the cure cycle on the final nanostructure of a PS‐block‐PMMA toughened epoxy. Asada et al examined the microphase separation using the same system as Kishi et al , and via in situ small‐angle X‐ray scattering they found that microphase separation occurred in two steps: first the BCP organized in micellic structures via self‐assembly in the uncured epoxy, and in a second step the BCP grew in size, and their distance to each other increased until the miscible PMMA blocks were finally assembled in the epoxy network. In this case, it was believed that the PMMA chain length mainly controlled the reorganization process.…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack propagation in triblock copolymer toughened epoxy nanocomposites

Klingler

Wetzel

2017

Polymer Engineering & Sci

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This study systematically investigates the influence of a Polymethylmethacrylate‐block‐Polybutylacrylate‐block‐Polymethylmethacrylate (PMMA‐b‐PBuA‐b‐PMMA) triblock copolymer (BCP) on the flexural properties, the static fracture toughness and especially the resistance to fatigue crack propagation (FCP) of a cycloaliphatic amine cured bisphenol A based epoxy resin (EP). The results show that already small concentrations of BCP can significantly improve fracture toughness and the resistance to fatigue crack propagation. Crack growth rate as well as the Paris' law exponent m were considerably reduced from m = 15.5 of the neat epoxy to m = 8.1 for the BCP toughened materials. Simultaneously, the resistance to fatigue crack propagation was found to increase drastically from a critical stress intensity factor range normalΔKIc of 0.39 MPam to 0.81 MPam. Fractography and structural analysis reveal that the improved resistance to fatigue crack propagation correlates to crack shielding and zone shielding mechanisms caused by the synergistic interaction of BCP‐rich domains and dispersed nanometer sized, presumably BCP‐rich particles in epoxy‐rich regions. POLYM. ENG. SCI., 57:579–587, 2017. © 2017 Society of Plastics Engineers

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Density Functional Theory for Polymer Phase Separations Induced by Coupling of Chemical Reaction and Elastic Stress

Oya

Kikugawa

Okabe

et al. 2021

Advcd Theory and Sims

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A density functional theory is applied to phase separation dynamics influenced by crosslinking reactions in dense polymer solutions. The crosslinking reaction is modeled by a change from non-crosslinked polymers comprising transient network (TN) to crosslinked polymers participating in the percolated permanent network (PN). Deformed TN polymers are considered to relax to the isotropic equilibrium state according to the Maxwellian linear viscoelastic constitutive equation, which is used in the modeling of viscoelastic phase separations. The PN is modeled by a linear elastic constitutive model. When TN polymers are taken into the PN by crosslinking reaction, the instantaneous deformation of the TN polymers are frozen, and such frozen deformations are accumulated as time goes on. A series of simulations is performed using this model, so that two specific features of the viscoelastic and reactive phase separation are obtained, i.e., 1) two-stage phase separation process that leads to a domain structure with two different characteristic length scales, and 2) fixing the phase-separated structure before reaching the macrophase separation.

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Effect of miscible PMMA chain length on disordered morphologies in epoxy/PMMA-b-PnBA-b-PMMA blends by in situ simultaneous SAXS/DSC

Cited by 21 publications

References 29 publications

Relationship between the mechanical properties of epoxy/PMMA-b-PnBA-b-PMMA block copolymer blends and their three-dimensional nanostructures

Relationship between the mechanical properties of epoxy/PMMA-b-PnBA-b-PMMA block copolymer blends and their three-dimensional nanostructures

Fatigue crack propagation in triblock copolymer toughened epoxy nanocomposites

Density Functional Theory for Polymer Phase Separations Induced by Coupling of Chemical Reaction and Elastic Stress

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