Micro- or nanoseparated phases in thermoset blends of an epoxy resin and PEO–PPO–PEO triblock copolymer

Larrañaga, Maider; Gabilondo, Nagore; Kortaberría, Galder; Serrano, Elena; Remiro, P. M.; Riccardi, C. C.; Mondragón, Iñaki

doi:10.1016/j.polymer.2005.05.102

Cited by 108 publications

(89 citation statements)

References 28 publications

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“…The resulting blends exhibit microstructures that depend on type of polymers, their concentrations and curing programs (time and temperature). [1][2][3] The majority of thermosetting polymer blends studied hitherto are immiscible; [4][5][6][7][8][9] as a result of competition among kinetic and thermodynamic factors. In cases where miscibility has been found, attempts were made to relate it to structural similarities and in particular to the presence of various secondary interaction forces (e.g., hydrogen bonding dH, [10,11] ion-dipole forces and electron-donor-acceptor interactions).…”

Section: Relation To Previous Workmentioning

confidence: 99%

“…study crystallization processes, miscibility, compatibility, and parameters controlling phase interactions. [1][2][3][4] PEO is a proton-accepting polyether known to exhibit strong interactions and miscibility with several polymers possessing functional acid groups, such as poly(acrylic acid) and poly(methacrylic acid) in which complexion occurs from strong acid hydroxyls. [12] An important example of miscible epoxy resin (ER) þ PEO mixtures is the blend of PEO with poly(hydroxyl ether of bisphenol-A) (phenoxy).…”

Section: Relation To Previous Workmentioning

confidence: 99%

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Thermophysical Properties and Molecular Relaxations in Cured Epoxy Resin + PEO Blends: Observations on Factors Controlling Miscibility

Kalogeras

Vassilikou‐Dova

Christakis

et al. 2006

Macro Chemistry & Physics

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Summary: Thermophysical properties and molecular relaxations in aromatic amine‐cured diglycidyl ether of bisphenol‐A (DGEBA) epoxy oligomer and poly(ethylene oxide) (PEO) mixtures were determined by DSC and dielectric techniques (TSC, DRS). The binary blends were judged to be fully miscible in the amorphous state (wPEO < 40 wt.‐%), as evidenced by the single composition‐dependent glass transition temperatures Tgs. In the amorphous blends, negative deviations of dielectric/thermal Tg‐estimates from the linear mixing rule or the behavior predicted by the Fox equation reveal weaker intermolecular interactions, compared to strong self‐association of hydroxyls in the cured thermoset. Morphological changes in PEO‐rich blends (wPEO ≥ 40 wt.‐%) are in accordance with their complicated interface structure, previously reported to consist of amorphous PEO regions, branched epoxy resin chains and an imperfect epoxy resin network located between PEO lamellae. In these blends, PEO crystallites exert steric hindrances in the amorphous regions, causing strong Tg upshifts. Changes in the relaxation dynamics of glyceryl segments (e.g., in the activation energy barrier and relaxation strength) are in accordance with the idea that the close matching between the molecular polarities of PEO, epoxy resin and the cure agent significantly contributes to the observed miscibility.

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Section: Relation To Previous Workmentioning

confidence: 99%

Section: Relation To Previous Workmentioning

confidence: 99%

Thermophysical Properties and Molecular Relaxations in Cured Epoxy Resin + PEO Blends: Observations on Factors Controlling Miscibility

Kalogeras

Vassilikou‐Dova

Christakis

et al. 2006

Macro Chemistry & Physics

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“…In this case, nanostructures are preferred as they would offer the significant toughening from rubber particles without imposing a heavy penalty in processing. Most of the early work on block copolymer modification of epoxy polymers has focused on the morphologies and mechanical properties, with less emphasis on the toughening mechanisms brought about by the respective morphologies [27][28][29][30][31]. The most commonly quoted toughening mechanisms observed were rubbery phase cavitation, debonding, plastic void growth and shear yielding with large damage zones [22,24,25].…”

Section: Introductionmentioning

confidence: 99%

The microstructure and fracture performance of styrene–butadiene–methylmethacrylate block copolymer-modified epoxy polymers

Chong

Taylor

2013

J Mater Sci

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The microstructure and fracture performance of an anhydride-cured epoxy polymer modified with two poly(styrene)-b-1,4-poly(butadiene)-b-poly(methyl methacrylate) (SBM) block copolymers were investigated in bulk form, and when used as the matrix material in carbon fibre reinforced composites. The 'E21' SBM block copolymer has a higher butadiene content and molecular weight than the 'E41'. A network of aggregated spherical micelles was observed for the E21 SBM modified epoxy, which became increasingly interconnected as the SBM content was increased. A steady increase in the fracture energy was measured with increasing E21 content, from 96 to 511 J/m 2 for 15 wt% of E21. Well-dispersed 'raspberry'-like SBM particles, with a sphere-on-sphere morphology of a poly(styrene) core covered with poly(butadiene) particles, in an epoxy matrix were obtained for loadings up to 7.5 wt% of E41 SBM. This changed to a partially phase-inverted structure at higher E41 contents, accompanied by a significant jump in the measured fracture energy to 1032 J/m 2 at 15 wt% of E41. The glass transition temperatures remained unchanged with the addition of SBM, indicating a complete phase separation. Electron microscopy and cross polarised transmission optical microscopy revealed localised shear band yielding, debonding and void growth as the main toughening mechanisms. Significant improvements in fracture energy were not observed in the fibre composites, indicating poor toughness transfer from the bulk to the composite. The fibre bridging observed for the unmodified epoxy matrix was reduced due to better fibre-matrix adhesion. The size of the crack tip deformation zone in the composites was restricted by the fibres, hence reducing the measured fracture energy compared to the bulk for the toughest matrix materials.

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“…DGEBA/DDM system modified with 30 wt % PMMA shows a cocontinuous morphology similar to that found by other authors for the same matrix modified with a higher molecular mass PMMA at lower curing temperatures. 11,45,46 When the monoamine content increases, cocontinuous structures are also obtained until a miscible mixture is observed when a monoamine : diamine ratio 75 : 25 is employed. In DGEBA/DDM system with 40 wt % modifier, the morphology completely changes, but it remains being cocontinuous.…”

Section: Resultsmentioning

confidence: 99%

Thermoplastic‐modified epoxy resins cured with different functionalities amine mixtures: Morphology, thermal behavior, and mechanical properties

Blanco

López

Arcaya

et al. 2009

J of Applied Polymer Sci

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Epoxy matrices inherent brittleness and poor crack resistance make necessary some form of toughening. In this work, to improve their fracture toughness and ductility epoxy matrices were modified by changing its architecture and by the addition of a third component. The matrices architecture were modified by stoichiometrically reacting a bifunctional epoxy resin with different functionalities amine mixtures, one of which being a monoamine that plays the role of chain extender. In the modification by the addition of a third component, poly(methyl methacrylate) (PMMA) was selected as modifier. PMMA is initially miscible with epoxy/amine systems but can phase separate during curing. The kinetics and miscibility of these systems were studied previously. At constant curing conditions, materials from completely opaque (phase separated) to transparent (miscible) can be obtained with the increase in monoamine content. In this work, the effects of the modifier content and of the monoamine : diamine ratio in stoichiometric epoxy/amine mixtures on the resultant morphologies as well as on their thermal and mechanical properties was studied

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Micro- or nanoseparated phases in thermoset blends of an epoxy resin and PEO–PPO–PEO triblock copolymer

Cited by 108 publications

References 28 publications

Thermophysical Properties and Molecular Relaxations in Cured Epoxy Resin + PEO Blends: Observations on Factors Controlling Miscibility

Thermophysical Properties and Molecular Relaxations in Cured Epoxy Resin + PEO Blends: Observations on Factors Controlling Miscibility

The microstructure and fracture performance of styrene–butadiene–methylmethacrylate block copolymer-modified epoxy polymers

Thermoplastic‐modified epoxy resins cured with different functionalities amine mixtures: Morphology, thermal behavior, and mechanical properties

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