Effect of Free-Volume Holes on Dynamic Mechanical Properties of Epoxy Resins for Carbon-Fiber-Reinforced Polymers

Zhang, Hongjun; Sellaiyan, S.; Kakizaki, T.; Uedono, Akira; Taniguchi, Y.; Hayashi, K.

doi:10.1021/acs.macromol.7b00472

Cited by 60 publications

(35 citation statements)

References 17 publications

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“…The behaviour depicted in Figure 2b, on the other hand, is derived from the singular log-linear relationship between modulus and specific volume found by Maeda and Paul [62], which is consistent with the numerical simulation analysis by Puosi and Leporini [63] and the experimental data of Zhang et al [64]. It should be noted, however, that behaviour at temperatures below the β transition has not been addressed in the literature on antiplasticization and, therefore, the traces shown are somewhat speculative.…”

Section: Comparison Of Antiplasticization With Physical Ageingsupporting

confidence: 89%

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

et al. 2020

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Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis includes the role of polymer/plasticizer molecular interactions and the conditions leading to the cross-over from antiplasticization to plasticization. This was based on molecular dynamics considerations of thermal transitions and related relaxation spectra, alongside the deviation of free volumes from the additivity rule. Useful insights were gained from an analysis of data on molecular glasses, including the implications of the glass fragility concept. The effects of molecular packing resulting from antiplasticization are also discussed in the context of physical ageing. These include considerations on the effects on mechanical properties and diffusion-controlled behaviour. Some peculiar features of antiplasticization regarding changes in Tg were probed and the effects of water were examined, both as a single component and in combination with other plasticizers to illustrate the role of intermolecular forces. The analysis has also brought to light the shortcomings of existing theories for disregarding the dual cross-over from antiplasticization to plasticization with respect to modulus variation with temperature and for not addressing failure related properties, such as yielding, crazing and fracture toughness.

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Section: Comparison Of Antiplasticization With Physical Ageingsupporting

confidence: 89%

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

et al. 2020

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“…The storage modulus and tan δ of various epoxy composites are shown in Figure 6 . The homogeneous dispersion of fillers in polymer matrix and their interfacial interaction will have a significant effect on the thermomechanical properties [ 33 , 34 ]. For epoxy composites containing IL-silica, IL-silica can be used both as curing agent and effective reinforce filler for epoxy composites.…”

Section: Resultsmentioning

confidence: 99%

Supported Ionic Liquid Silica as Curing Agent for Epoxy Composites with Improved Mechanical and Thermal Properties

Zhang

Tian

et al. 2017

Polymers

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Abstract:The present study aims to improve the mechanical properties of epoxy composite by incorporating supported ionic liquid silica (IL-silica). The IL-silica not only showed improved interfacial interaction and reinforcement, but also served as cure agent of epoxy composites. The differential scanning calorimetry analysis revealed that epoxy composites could be successfully cured with IL-silica without any routine curing agents. IL-silica/epoxy composites presented higher mechanical and thermal properties compared with epoxy composite containing un-functionalized silica (u-silica). The dynamic mechanical analysis showed that the storage modulus of composites significantly increased with the addition of IL-silica in comparison to that with added u-silica, as well as the variation of Tg parameter. The incorporation of IL-silica simultaneously enhanced the tensile strength, toughness, and thermal stability of the epoxy composites. The considerable improvements in mechanical and thermal properties are ascribed to the improved dispersion of IL-silica and the enhanced interfacial interactions between epoxy matrix and IL-silica by strong covalent bonding, which results in an effective load transfer.

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“…Although not univocally defined [ 1 ], the free volume is a useful concept to explain various features of polymers such as mechanical properties [ 2 ], diffusivity of permeants [ 3 ], or aging [ 4 ]. Therefore, the evaluation of the free volume is important not only for basic science, but also to design polymers with tailored properties for specific applications.…”

Section: Introductionmentioning

confidence: 99%

Shape and Temperature Expansion of Free Volume Holes in Some Cured Polybutadiene-Polyisoprene Rubber Blends

Consolati

Mossini

Nichetti³

et al. 2021

IJMS

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The free volume fraction of a macromolecular structure can be assessed theoretically by using a suitable model; however, it can also be evaluated from experimental data obtained from dilatometry and positron annihilation lifetime spectra. In this second case, a regular geometry of the sub-nanometric cavities forming the free volume has to be assumed, although in fact they are irregularly shaped. The most popular approach is to guess spherical holes, which implies an isotropic growth of these last with temperature. In this work, we compared the free volume fraction, as obtained from experiments in a set of polybutadiene and polyisoprene cured rubbers and their blends, with the analogous quantity expected by using the lattice-hole model. The results allowed us to obtain insights on the approximate shape of the holes. Indeed, a cylindrical flattened geometry of the cavities produced a better agreement with the theory than the spherical shape. Furthermore, the best fit was obtained for holes that expanded preferentially in the radial direction, with a consequent decrease of the aspect ratio with temperature.

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Effect of Free-Volume Holes on Dynamic Mechanical Properties of Epoxy Resins for Carbon-Fiber-Reinforced Polymers

Cited by 60 publications

References 17 publications

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

Supported Ionic Liquid Silica as Curing Agent for Epoxy Composites with Improved Mechanical and Thermal Properties

Shape and Temperature Expansion of Free Volume Holes in Some Cured Polybutadiene-Polyisoprene Rubber Blends

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