Curing cycloaliphatic epoxy resin with 4-methylhexahydrophthalic anhydride: Catalyzed vs. uncatalyzed reaction

Barabanova, A. I.; Lokshin, B. V.; Kharitonova, Elena P.; Afanasyev, E. S.; Аскадский, А.А.; Philippova, Olga E.

doi:10.1016/j.polymer.2019.121590

Cited by 20 publications

(30 citation statements)

References 34 publications

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“…From FT-IR data it can be obtained that the final monomer conversions of systems without Zn(acac) 2 −H 2 O are comparable to catalysed ones, albeit they are reached at longer curing times. This is in good agreement with previous work on epoxy-anhydride systems demonstrating that the catalyst mainly influences the cure rate but not the final monomer conversion [34]. To ensure maximum conversion of the monomers, which was monitored by the disappearance of the epoxy band at 910 cm −1 , all networks were cured at 120 • C for 20 h.…”

Section: Design and Curing Of High-t G Epoxy-anhydride Vitrimerssupporting

confidence: 90%

“…Independent of the epoxy monomer, the T g of non-catalysed networks is higher than the catalysed ones. This behaviour was also found in other epoxy-anhydride networks and is related to a faster curing of the resin in the presence of a catalyst, which affects the network structure and leads to a lower cross-linking density [34,37]. With increasing concentration of the catalyst, this effect is more pronounced and a steady decrease of the T g values is obtained [38].…”

Section: Thermal and Thermo-mechanical Properties Of High-t G Epoxy-asupporting

confidence: 58%

“…In the base catalysed ring-opening reaction, the tertiary amine groups open the epoxy rings under the formation of alkoxides ( Figure 2 b) [ 32 , 34 , 36 ]. The alkoxides react with anhydride groups yielding carboxylate anions, which are again able to open epoxy moieties.…”

Section: Resultsmentioning

confidence: 99%

“…The results clearly show the presence of non-reacted epoxy groups (~6%) giving rise to an incomplete homopolymerization of 3-DGOA. This is mainly due to diffusion limitations of the monomers above the gel point and which are typically observed in aromatic epoxies at high degrees of conversion (>90%) [32][33][34]. During the course of the curing reaction, the mobility of the monomers decreases due to the high viscosity of the matrix and the reaction becomes diffusion controlled since the diffusion of reactive species toward each other is hindered.…”

Section: Design and Curing Of High-t G Epoxy-anhydride Vitrimersmentioning

confidence: 99%

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Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation

et al. 2020

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Epoxy-anhydride vitrimers are covalent adaptable networks, which undergo associative bond exchange reactions at elevated temperature. Their service temperature is influenced by the glass transition temperature (Tg) as well as the topology freezing transition temperature (Tv), at which the covalent bond exchange reactions become significantly fast. The present work highlights the design of high-Tg epoxy-anhydride vitrimers that comprise an efficient stress relaxation at elevated temperature. Networks are prepared by thermally curing aminoglycidyl monomers with glutaric anhydride in different stoichiometric ratios. The tertiary amine groups present in the structure of the aminoglycidyl derivatives not only accelerate the curing reaction but also catalyse the transesterification reaction above Tv, as shown in stress relaxation measurements. The topology rearrangements render the networks recyclable, which is demonstrated by reprocessing a grinded powder of the cured materials in a hot press. The epoxy-anhydride vitrimers are characterised by a high Tg (up to 140 °C) and an adequate storage modulus at 25 °C (~2.5 GPa), which makes them interesting candidates for structural applications operating at high service temperature.

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Section: Design and Curing Of High-t G Epoxy-anhydride Vitrimerssupporting

confidence: 90%

Section: Thermal and Thermo-mechanical Properties Of High-t G Epoxy-asupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Section: Design and Curing Of High-t G Epoxy-anhydride Vitrimersmentioning

confidence: 99%

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Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation

et al. 2020

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“…The data are shown in Figure 5 and Table 2. The first temperature transition (T g ) is associated with devitrification of the material [51]. The second temperature transition (T v ) appears only in the vitrimers [1,3] and reflects defrosting of the topology of polymer networks when the sample is heated.…”

Section: Mechanical and Thermal Properties Of Epoxy/silica Vitrimer Nanocompositesmentioning

confidence: 99%

Unmodified Silica Nanoparticles Enhance Mechanical Properties and Welding Ability of Epoxy Thermosets with Tunable Vitrimer Matrix

et al. 2021

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Epoxy/silica thermosets with tunable matrix (vitrimers) were prepared by thermal curing of diglycidyl ether of bisphenol A (DGEBA) in the presence of a hardener—4-methylhexahydrophthalic anhydride (MHHPA), a transesterification catalyst—zinc acetylacetonate (ZAA), and 10–15 nm spherical silica nanoparticles. The properties of the resulting material were studied by tensile testing, thermomechanical and dynamic mechanical analysis. It is shown that at room temperature the introduction of 5–10 wt% of silica nanoparticles in the vitrimer matrix strengthens the material leading to the increase of the elastic modulus by 44% and the tensile stress by 25%. Simultaneously, nanoparticles enhance the dimensional stability of the material since they reduce the coefficient of thermal expansion. At the same time, the transesterification catalyst provides the thermoset with the welding ability at heating, when the chain exchange reactions are accelerated. For the first time, it was shown that the silica nanoparticles strengthen welding joints in vitrimers, which is extremely important, since it allows to repeatedly use products made of thermosets and heal defects in them. Such materials hold great promise for use in durable protective coatings, adhesives, sealants and many other applications.

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The impact of water released from boehmite nanoparticles during curing in epoxy‐based nanocomposites

Waniek

Braun

Silbernagl

et al. 2021

J of Applied Polymer Sci

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The enhancing effect on mechanical properties of boehmite (γ‐AlOOH) nanoparticles (BNP) in epoxy‐based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro‐ and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action. With FTIR‐spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail. The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation.

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Curing cycloaliphatic epoxy resin with 4-methylhexahydrophthalic anhydride: Catalyzed vs. uncatalyzed reaction

Cited by 20 publications

References 34 publications

Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation

Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation

Unmodified Silica Nanoparticles Enhance Mechanical Properties and Welding Ability of Epoxy Thermosets with Tunable Vitrimer Matrix

The impact of water released from boehmite nanoparticles during curing in epoxy‐based nanocomposites

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