Probing the glass transition in reversible cross-linked polymer composites

Peng, Yong-jin; Cai, Chenting; Wang, Changjun; Zuo, Zhili; Liu, Xuezheng

doi:10.1039/c9ra01942a

Cited by 4 publications

(3 citation statements)

References 30 publications

(30 reference statements)

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“…Figure 4 shows the carbon spectrum of sample 100/0 and the corresponding nucleus signal assignment. [28,37] The occurrence of the DA reaction was confirmed by the signals at 178, 90, and 80 ppm corresponding to carbons "a," "j," and "k" of the generated DA adduct.…”

Section: Methodsmentioning

confidence: 87%

“…[17,23,24] Finally, other authors describe the crosslinking of a furan-functionalized epoxy prepolymer with bismaleimide. [18,[25][26][27][28][29] All these works avoid the direct contact between the bismaleimide and the amine to eliminate the possibility of the Michael's reaction. However, in recent work, [30,31] epoxy networks have been obtained by curing an epoxy resin with a conventional diamine and consecutively via DA reaction in order to get an epoxy coating with anticorrosion and self-healing properties.…”

Section: Introductionmentioning

confidence: 99%

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Recyclable Epoxy Resin via Simultaneous Dual Permanent/Reversible Crosslinking Based on Diels–Alder Chemistry

Puyadena

Calafel

Román

et al. 2021

Macro Chemistry & Physics

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Taking advantage of the reversible Diels-Alder (DA) reaction, a simple strategy to obtain recyclable epoxy resins is presented. For this purpose, blends of furan-functionalized and nonfunctionalized epoxy resin are prepared. After the addition of diamine and bismaleimide, blends are heated at 150°C for 5 min, where the permanent amine/epoxy reaction has taken place and upon cooling to room temperature the reversible DA reaction has happened, giving rise to a dual permanent/nonpermanent network. Both reactions are confirmed by Fourier-transform infrared (FTIR) and 13 C-crosspolarization, magic-angle spinning (CP/MAS) nuclear magnetic resonance (NMR). Modulated differential scanning calorimetry (MDSC)shows that the epoxy/amine and bismaleimide/amine curing reaction take place, after the DA reaction, simultaneously with the retroDA reaction and before the bismaleimide homopolymerization. Therefore, under the appropriate curing conditions, the Michael's addition and the bismaleimide homopolymerization do not avoid the formation of a hybrid network, as stated in other reports. The reversibility of the DA reaction in three consecutive cycles is confirmed by DSC. Finally, the dual-cured sample is reprocessed three times without significant loss of mechanical properties.

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Section: Methodsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Recyclable Epoxy Resin via Simultaneous Dual Permanent/Reversible Crosslinking Based on Diels–Alder Chemistry

Puyadena

Calafel

Román

et al. 2021

Macro Chemistry & Physics

View full text Add to dashboard Cite

show abstract

“…In addition to conventional TGA and differential scanning calorimetry (DSC), sample-controlled thermal analysis (HiRes TGA), modulated TGA (MTGA), and modulated DSC (MDSC) will be considered. Peng et al used MDSC in the study of four-armed cross-linked polymers obtained via furan/maleimide DA reaction to separate the glass transition region (reversing heat flow signal) and the rDA reaction (non-reversing heat flow signal) [28]. These two phenomena appeared to be overlapping in the total heat flow signal.…”

Section: Introductionmentioning

confidence: 99%

Evidence through Thermal Analysis of Retro Diels-Alder Reaction in Model Networks Based on Anthracene Modified Polyester Resins

Ionita,

Cristea,

Gaina

et al. 2023

Polymers

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The present work is focused on polyester resins obtained from the diglycidyl ether of bisphenol A and anthracene modified 5-maleimidoisophthalic acid. Because the maleimide-anthracene Diels–Alder (DA) adduct is stable at high temperatures, it is considered a good option for high performance polymers. However, the information related to the retroDA reaction for this type of adduct is sometimes incoherent. A detailed thermal study (conventional TGA, HiRes TGA, MTGA, DSC, MDSC) was performed in order to establish whether the rDA reaction can be revealed for this type of anthracene modified polyester resins. The TGA method confirmed the cleavage of the anthracene–maleimide DA adduct, while the DSC demonstrated the presence of anthracene in the system. At high temperatures, unprotected maleimide homopolymerizes and/or reacts with allyl groups according to the –ene reaction. Therefore, the thermal DA reaction is not displayed anymore upon the subsequent cooling, and the glass transition region is registered at a higher temperature range during the second heating. The use of sample-controlled thermal analysis (HiRes TGA) and MTGA improved the TGA result; however, it was not possible to separate the very complex degradation processes that are interconnected.

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Click Reactions in Polymer Synthesis

Huang

Qin

Tang

2021

Encyclopedia of Polymer Science and Technology

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Click reactions, with remarkable merits including high efficiency, atom economy, mild reaction conditions, good functionality tolerance, simple isolation process, and regio‐ and/or stereoselectivity, have drawn intense attention of polymer chemists and found widespread applications in polymer synthesis. Besides the famous Cu(I)‐catalyzed azide–alkyne click reaction, plentiful click reactions, such as Diels–Alder, thiol‐based, nonaldol carbonyl, amino‐yne, hydroxyl–yne, and sulfur(VI) fluoride‐exchange click reactions, have also been introduced into the field of polymer chemistry. With these efficient click reactions in hand, diverse functional groups can be readily incorporated into polymer chains to endow them with desired functionalities. Copolymers with complex structures, such as block, graft, star, and cyclic polymers, can be synthesized using click reaction as polymer conjugation method. These click reactions have also been developed into facile polymerization techniques, that is, click polymerization, for the direct synthesis of linear, hyperbranched, and cross‐linked polymers with various properties. This article intends to give a brief summary of click reactions applied in polymer synthesis, including preparation of polymers and postpolymerization modification of preformed polymers.

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Probing the glass transition in reversible cross-linked polymer composites

Abstract: Understanding the nature of glass transition is still a great challenge.

Cited by 4 publications

References 30 publications

Recyclable Epoxy Resin via Simultaneous Dual Permanent/Reversible Crosslinking Based on Diels–Alder Chemistry

Recyclable Epoxy Resin via Simultaneous Dual Permanent/Reversible Crosslinking Based on Diels–Alder Chemistry

Evidence through Thermal Analysis of Retro Diels-Alder Reaction in Model Networks Based on Anthracene Modified Polyester Resins

Click Reactions in Polymer Synthesis

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