Large-scale heterogeneities in randomly cross-linked networks

Bastide, J.; Leibler, Ludwik

doi:10.1021/ma00186a058

Cited by 317 publications

(247 citation statements)

References 5 publications

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“…Before elongation, both USAXS and SAXS show anisotropy, which would arise in the sample preparation process. By increasing the elongation ratio, USAXS images at BL20XU show a butterfly pattern, which is well known for a stretched gel (Bastide & Leibler, 1988). In the case of a stretched gel, the butterfly pattern originates from the inhomogeneity of cross-links under elongation.…”

Section: Figurementioning

confidence: 69%

Characterization of two-dimensional ultra-small-angle X-ray scattering apparatus for application to rubber filled with spherical silica under elongation

Shinohara

Kishimoto²,

Inoue

et al. 2007

J Appl Cryst

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Two‐dimensional ultra‐small‐angle X‐ray scattering (2D‐USAXS) apparatus at SPring‐8 has been characterized. 2D‐USAXS is a promising tool to study the structural change of the hierachical aggregate structure of fillers such as carbon black and silica particles in rubber. The aggregate structure of fillers is key to understanding the reinforcement effects which fillers show in rubber. We have applied 2D‐USAXS to rubber filled with spherical silica particles and proved it to be a powerful technique.

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Section: Figurementioning

confidence: 69%

Characterization of two-dimensional ultra-small-angle X-ray scattering apparatus for application to rubber filled with spherical silica under elongation

Shinohara

Kishimoto²,

Inoue

et al. 2007

J Appl Cryst

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“…17 These inhomogeneities usually increase with the swelling or deformation since the cross-linking junctions are permanently fixed on the polymer chains and the gel cannot adjust its cross-link distribution or polymer length in the network when its environment changes. 17 As a result, the usual chemical gel shows an abnormal butterfly pattern, [81][82][83][84][85][86][87] i.e., prolate patterns parallel to the stretching direction; this behavior was qualitatively explained by Onuki 88 and Panykov and Rabin. 89,90 However, the slide-ring gel shows a normal butterfly pattern, i.e., prolate patterns perpendicular to the stretching direction as shown in Figure 4.…”

Section: Scattering Studies Of Slide-ring Gelsmentioning

confidence: 96%

Novel Cross-Linking Concept of Polymer Network: Synthesis, Structure, and Properties of Slide-Ring Gels with Freely Movable Junctions

Ito

2007

Polym J

374

298

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ABSTRACT:We have recently developed a novel type of gel called the slide-ring gel or topological gel that is different from physical and chemical gels by using the supramolecular architecture with topological characteristics. In this gel, polymer chains with bulky end groups exhibit neither covalently cross-links as in chemical gels nor attractive interactions as in physical gels but are topologically interlocked by figure-of-eight cross-links. Hence, these crosslinks can pass along the polymer chains freely to equalize the tension of the threading polymer chains similarly to pulleys; this is called the pulley effect. The slide-ring gel is a new cross-linking concept for the polymer network as well as a real example of a slip-link model or sliding gel, which was previously considered only theoretically. In this study, we review the synthesis, structure, and mechanical properties of the slide-ring gels with freely movable cross-linking junctions based primarily on our recent studies. The pulley effect of the slide-ring gels has been recently confirmed by mechanical measurements, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), quasi-elastic light scattering (QELS), etc. This concept can be applied to not only gels but also to a wide variety of polymeric materials without solvents.

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“…We discuss the correlation between the hierarchical, two-step internal fracture and the heterogeneity of the PAMPS network. It is well known that common gels contain spatial inhomogeneity in the network 23,24 . One reason is frozen concentration fluctuation by gelation 23 .…”

mentioning

confidence: 99%

“…It is well known that common gels contain spatial inhomogeneity in the network 23,24 . One reason is frozen concentration fluctuation by gelation 23 . The other reason, which is specific for gels synthesized from monomers and cross-linkers, is hierarchical 5 gelation process which results in spatial inhomogeneity of crosslinking points 24 .…”

mentioning

confidence: 99%

Characterization of internal fracture process of double network hydrogels under uniaxial elongation

et al. 2013

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5Previously we revealed that the high toughness of double network hydrogels (DN gels) derives from the internal fracture of the brittle network during deformation, which dissipates energy as sacrificial bonds. In this study, we intend to elucidate the detailed internal fracture process of DN gels. We quantitatively analysed the tensile hysteresis and re-swelling behaviour of a DN gel that shows a well-defined necking and strain hardening, and obtained the following new findings: 1) Fracture of the 1 st network PAMPS 10 starts far below the yielding strain, and 90% of the initially load-bearing PAMPS chains already breaks at the necking point.2) The dominant internal fracture process occurs in the necking and hardening region although the softening mainly occurs before necking.3) The internal fracture efficiency is very high, 85% of the work is used for the internal fracture and 9% of all PAMPS chains break at sample failure. 4) The internal fracture is anisotropic, fracture occurs preferentially perpendicular to the tensile direction than 15 other two directions, but the fracture anisotropy decreases in the hardening region. Result 1) and 2) is in agreement with a hierarchical structural model of PAMPS network. Based on these findings, we present a revised description of the fracture process of DN gels.

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Large-scale heterogeneities in randomly cross-linked networks

Cited by 317 publications

References 5 publications

Characterization of two-dimensional ultra-small-angle X-ray scattering apparatus for application to rubber filled with spherical silica under elongation

Characterization of two-dimensional ultra-small-angle X-ray scattering apparatus for application to rubber filled with spherical silica under elongation

Novel Cross-Linking Concept of Polymer Network: Synthesis, Structure, and Properties of Slide-Ring Gels with Freely Movable Junctions

Characterization of internal fracture process of double network hydrogels under uniaxial elongation

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