Analysis of the damage zone around the crack tip for two rubber-modified epoxy matrices exhibiting different toughenability

Arias, María Laura; Frontini, Patricia María; Williams, Roberto J. J.

doi:10.1016/s0032-3861(02)00829-7

Cited by 92 publications

(54 citation statements)

References 21 publications

(12 reference statements)

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“…The lack of a further increase in secondary amine conversion shows that although there are still many remaining reactive secondary amine sites, they are unable to react with epoxide groups because of already being immobilized in the rigid network. [13] Since the oxygen atom present in the polyether chains of DEGBA-piperidine acts as a hinge in the network structure, [9] it could facilitate the formation of an amino-rich region around the silica particles. After the reaction of the silica with the amine, the reaction rate slows down and can gradually provide more amine at the interphase towards the end of the curing reaction.…”

Section: Cure Kineticsmentioning

confidence: 99%

Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure

Rosso

2007

Macromol. Rapid Commun.

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This study reveals the influence of silica nanoparticles on the cure reactions of a diglycidyl ether of bisphenol A epoxy resin. As soon as the silica nanoparticles are added to the neat resin (1, 3, and 5 vol.‐%), the total degree of conversion increases with an increasing amount of nanoparticles, and the cure reaction shows a more complex autocatalytic behaviour, which can not be described by a traditional kinetic model. Results from subsequent thermo‐mechanical analyses confirm an alteration in the microstructure attributable only to the presence of the nanoparticles in the curing stage. An amino‐rich interphase around the reactive treated particles is formed, which shifts the resin/hardener ratio, and benefits the homopolymerization of the epoxy and leads to a more highly crosslinked epoxy network. At the same time, the nanophase consists of a core‐shell structure with the rigid particle inside and a rubber‐like shell because of the excess hardener in this region.TEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.magnified imageTEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.

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Section: Cure Kineticsmentioning

confidence: 99%

Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure

Rosso

2007

Macromol. Rapid Commun.

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“…When the blends were cured at controlled conditions, a phase separation between the rubber particles and epoxy matrix was induced. However, the reports on epoxy modification with CTBN mainly focused on high temperature curing systems [7][8][9][10][11][12] , which mixed CTBN, EP and the curing agents directly, then reacted and cured at high temperature. The high temperature curing process had some disadvantages in factual applications.…”

Section: Introductionmentioning

confidence: 99%

Performance of CTBN(carboxyl-terminated poly (butadiene-co-acrylonitrile))-EP(diglycidyl ether of bisphenol-A (DGEBA)) prepolymers and CTBN-EP/polyetheramine (PEA) system

Shi

Zhang

et al. 2009

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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CTBN-EP prepolymers were synthesized from CTBN and epoxy resin under the catalysis of HTMAB. FTIR analyses indicate the formation of ester group between the carboxyl group of CTBN and the oxirane group of epoxy resin. The viscosity of modified prepolymer increases with CTBN content increasing, but the epoxy value of the prepolymer decreases greatly. DSC analyses verify that CTBN affects the curing process of CTBN-EP/PEA system. Mechanical testing presents the improved toughness of CTBN-EP/PEA curings for the decrease of tensile strength, flexural strength and compressive strength, and increase of impact strength and elongation-at-break with the CTBN content increasing. SEM micrographs show the rubber phase with many holes in diameter about 0.5-1.5 μm is formed when CTBN content is lower than 10 phr. However, the pattern of SEM graph shows some stalactite-like strips when CTBN content is higher than 15 phr. Furthermore, the SEM image of 25 phr CTBN sample forms a kind of co-continuous structure.

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“…Transmitted optical microscopy, TOM, was employed to examine the damage zone around the surviving crack tip. Thin sections were obtained using conventional grinding-polishing techniques [28,29]. First, a block was cut by sectioning normal to the fracture surface but parallel to the direction of crack propagation.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Synthesis and properties of epoxy-phenolic clay nanocomposites

Auad¹,

Nutt²,

Pettarín³

et al. 2007

Express Polym. Lett.

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Abstract. An epoxy-phenolic resin suitable for use as a composite matrix was reinforced with modified nanoclay (montmorillonite type). Characterization by x-ray diffraction and transmission electron microscopy (TEM) demonstrated that intercalated nanocomposites were formed with an inter-gallery distance of approximately 10 nm. The influence of nanoparticles on tensile strength and modulus, fracture toughness, and impact toughness was measured and compared with the unreinforced polymer. The results revealed that the maximum enhancement in stiffness and toughness was achieved with 2.5 wt% filler content. The enhancement in toughness behavior was attributed to the activation of multiple energy-dissipating damage mechanisms in the nanocomposites.

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Analysis of the damage zone around the crack tip for two rubber-modified epoxy matrices exhibiting different toughenability

Cited by 92 publications

References 21 publications

Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure

Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure

Performance of CTBN(carboxyl-terminated poly (butadiene-co-acrylonitrile))-EP(diglycidyl ether of bisphenol-A (DGEBA)) prepolymers and CTBN-EP/polyetheramine (PEA) system

Synthesis and properties of epoxy-phenolic clay nanocomposites

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