Effect of free-volume holes on static mechanical properties of epoxy resins studied by positron annihilation and PVT experiments

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

doi:10.1016/j.polymer.2020.122225

Cited by 22 publications

(18 citation statements)

References 28 publications

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“…One limitation of the FFV h parameter as calculated is that the packing density embedded within it does not take into account different spatial arrangements due to the regioisomeric SD-PUMs. The positron annihilation lifetime spectroscopy measurement (PALS) [32][33][34] is a unique probe for characterizing the local hole volume in networks and could also be used to measure FFV h , though it has been reported that densely cross-linked networks such as epoxy networks tend to have small hole volumes that push the limit of the PALS method. 35 The data Fig.…”

Section: Preparation and Characterization Of Sd-pum Networkmentioning

confidence: 99%

Effect of backbone and end-group regioisomerism on thermomechanical properties of vanillin-based polyurethane networks

Rangamani

Alabi

2021

Polym. Chem.

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Section: Preparation and Characterization Of Sd-pum Networkmentioning

confidence: 99%

Effect of backbone and end-group regioisomerism on thermomechanical properties of vanillin-based polyurethane networks

Rangamani

Alabi

2021

Polym. Chem.

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“… 47 Herein, positron annihilation lifetime spectroscopy (PALS) was performed to evaluate the size of the free-volume holes of the polymer coatings. 48 PALS data was analyzed using the LTv9 program, and all spectra were divided into different lifetime components (τ 1 < τ 2 < τ 3 ). The longest lifetime component τ 3 generally corresponds to the pick-off annihilation of ortho -positronium ( o -Ps), which provides information about the size of the free-volume holes.…”

Section: Resultsmentioning

confidence: 99%

Highly Cross-linked Epoxy Coating for Barring Organophosphate Chemical Warfare Agent Permeation

Zhang

et al. 2022

ACS Omega

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Chemical warfare agents (CWAs) can be absorbed in polymeric coatings through absorption and permeation, thus presenting a lethal touch and vapor hazards to people. Developing a highly impermeable polymer coating against CWAs, especially against organophosphate CWAs (OPs), is challenging and desirable. Herein, fluorinated epoxy (F-EP) and epoxy (EP) coatings with different cross-link densities were prepared to resist OPs. The effects of the polymer coating structure, including cross-link density, chemical composition and free volume, on the chemical resistance to dimethyl methylphosphonate (DMMP, Soman simulant) were investigated in detail. Meanwhile, the chemical resistance to Soman and VX was examined. The results reveal that the cross-link density is a critical factor in determining the chemical resistance of the coatings. Highly cross-linked EP and F-EP coatings with dense and solid cross-linked networks can fully bar DMMP and OPs permeation during the test time. At low or medium cross-link densities, the EP coating with a lower retention of DMMP exhibited a higher resistance than the F-EP coating due to the lower interaction with DMMP and smaller free-volume holes and lower relative fractional free volume. These results suggest that increasing the cross-link density is a reasonable approach to control the chemical resistance of polymer networks against OPs.

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“…Plasticization effect can be quantitatively evaluated by means of PALS. [39][40][41][42][43] All PALS spectra were resolved into three lifetime components, first (τ 1 ), second (τ 2 ), and long-lived third (τ 3 ) component. The τ 3 of the positronium corresponds to the pick-off annihilation of ortho-positronium (o-Ps) in the free-volume holes, which is the longest lifetime component.…”

Section: Free Volume Of the Lead-containing Plexiglassmentioning

confidence: 99%

Insight into the role of free volume in irradiation resistance to discoloration of lead‐containing plexiglass

Zhang

Chen

Zhao

et al. 2021

J of Applied Polymer Sci

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Lead‐containing plexiglass is prepared successfully via copolymerization of lead‐methacrylate (Pb(MAA)2 and the acrylic monomer such as methyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate. The results show that as‐prepared plexiglass has good photons shielding performance and resistance to the discoloration induced by radiation (10 kGy γ‐ray), and the alteration of shielding performance can be well described by the Monte Carlo Code simulations (MCNP5). Using two plasticized systems, the external‐plasticized one with various n‐octanoic acid concentrations and the internal‐plasticized one with different acrylic monomer, as the target samples, it is found that free volume plays dominant role in the irradiation resistance via the positron annihilation lifetime spectroscopy and electron paramagnetic resonance characterizations. The larger the free volume, the greater the quenching probability of free radicals during irradiation. Because the primary type of radiation‐induced color centers are annealable color centers, the effect of annealing of irradiation‐induced discoloration of lead‐containing plexiglass is remarkable. Differing from common treatments of improving irradiation resistance, the increased free volume via plasticization gives plexiglass good resistance to discoloration. This study discloses valuable information around improving irradiation shielding performance and resistance to the radiation‐induced discoloration for the plexiglass‐based materials.

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Effect of free-volume holes on static mechanical properties of epoxy resins studied by positron annihilation and PVT experiments

Cited by 22 publications

References 28 publications

Effect of backbone and end-group regioisomerism on thermomechanical properties of vanillin-based polyurethane networks

Effect of backbone and end-group regioisomerism on thermomechanical properties of vanillin-based polyurethane networks

Highly Cross-linked Epoxy Coating for Barring Organophosphate Chemical Warfare Agent Permeation

Insight into the role of free volume in irradiation resistance to discoloration of lead‐containing plexiglass

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