Effects of matrix ductility on rubber/matrix interfacially modified epoxy resins

Chen, Teng Ko; Shy, Horng Jan

doi:10.1016/0032-3861(92)91063-8

Cited by 20 publications

(13 citation statements)

References 12 publications

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“…According to several authors,3–7 an effective toughening mechanism is reached when the rubber modifier, which is soluble in the resin, precipitates before gelation of the resin. The cured resin contains fine precipitate rubbery particles which impart an enhanced resistance to crack propagation and impact strength 11. The tensions applied in the cured epoxy matrix (A) are dissipated by the elastomer particles (B) which act as an initiation site for the plastic shear deformation of the matrix.…”

Section: Introductionmentioning

confidence: 99%

“…The tensions applied in the cured epoxy matrix (A) are dissipated by the elastomer particles (B) which act as an initiation site for the plastic shear deformation of the matrix. Cavitation of the rubbery particles provides an additional dissipation of energy because the voids (C) produced during cavitation originate at points of the concentration of tension 11–14. The process of the dissipation of tension in rubber‐modified ER and the formation of voids are illustrated in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Modification of epoxy resin by isocyanate‐terminated polybutadiene

Barcia

Abrahão

Soares

2001

J of Applied Polymer Sci

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Hydroxy-terminated polybutadiene was functionalized with isocyanate groups and employed in preparation of a block copolymer of polybutadiene and bisphenol A diglycidyl ether (DGEBA)-based epoxy resin. The block copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy and size-exclusion chromatography (SEC). Cured blends of epoxy resin and hydroxy-terminated polybutadiene (HTPB) or a corresponding block copolymer were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMTA), and scanning electron microscopy (SEM). All modified epoxy resin networks presented improved impact resistance with the addition of the rubber component at a proportion up to 10 wt % when compared to the neat cured resin. The modification with HTPB resulted in milky cured materials with phase-separated morphology. Epoxy resin blends with the block copolymer resulted in cured transparent and flexible materials with outstanding impact resistance and lower glass transition temperatures. No phase separation was discernible in blends with the block copolymer.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modification of epoxy resin by isocyanate‐terminated polybutadiene

Barcia

Abrahão

Soares

2001

J of Applied Polymer Sci

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“…[1][2][3][4][5] These heterophase materials exhibit substantial enhancement in fracture toughness, not only relatively to the parent homogeneously cured resin, but also in comparison to the chemically equivalent bicomponent system where phase separation takes place through the formation of nanostructured interpenetrating networks (IPNs). 6 Invariably, the morphology of the particulate domains consists of a flocculation of small primary particles (Ͻ1 m) encapsulated in a different network, which binds them to form larger secondary particles (ca.…”

Section: Introductionmentioning

confidence: 99%

“…These are frequently referred to as liquid rubbers 8 and their composition is tailored to render them miscible with conventional epoxy resins, such as the diglycidyl ether of bisphenol A (DGEBA). [2][3][4]9,10 The terminal functionalities are either carboxylic acid or primary amine and the oligomers are known as CTBN and ATBN, respectively. Several other functionalized oligomers have also been used to enhance the fracture toughness of epoxy resins.…”

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confidence: 99%

Silane functionalization of perfluoroether oligomers for reaction management and morphology control of two‐phase epoxy networks

Mascia

Heath

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:Mixtures of an epoxy resin, hardener, and acid functionalized perfluoroether oligomers will readily undergo phase separation during curing. However, the conditions to bring about the growth of nuclei into microscopic particles have hitherto been found only for systems cured with anhydrides. In the present study perfluoroether oligomers were functionalized by established procedures to introduce both carboxylic acid groups and alkoxysilane groups in sites within the chain extended segments. The presence of alkoxysilane groups together with the prereaction step with an excess epoxy resin, prior to the addition of the aromatic amine hardener, induced phase separation by a nucleation-and-growth mechanism. The dual functionality in the perfluoroether oligomer was even more beneficial when the alkoxysilane groups were hydrolyzed prior to the addition of the amine hardener. Under such circumstances the precipitation of the perfluoroether oligomer occurred quantitatively, as indicated by the complete absence of any plasticization effects in the epoxy matrix. From electron microscopy examinations, thermal analysis, and measurements of mechanical properties it was possible to deduce a plausible mechanism for the formation of the typical coreshell aggregates within the precipitated particles for these systems, which could also be applied to other systems, such as those using carboxylic-acid-terminated butadiene acrylonitrile oligomers.

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“…In these stud- 5 ies, it has been shown that reactions between the resin and the toughening agent prior to the onset of gelation give rise to the formation of fine rubbery precipitated particles (1 -5 m) which impart an enhanced resistance to crack propagation and impact strength. Allowing the rubbery phase to separate 6 totally from the matrix ensures that the epoxy network remains essentially unchanged. In this way the cured system will retain most of the original physical properties of the unmodified resin.…”

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confidence: 97%