Comb-shaped aromatic polyamide cross-linked by Diels-Alder chemistry: Towards recyclable and high-performance thermosets

Luo, Kaiju; Li, Jing; Duan, Guangyu; Wang, Yan; Yu, Junrong; Zhu, Jing; Hu, Zuming

doi:10.1016/j.polymer.2018.03.026

Cited by 33 publications

(27 citation statements)

References 51 publications

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“…Solvolysis experiments were previously performed by immersing samples of the different composites in different high boiling solvents, such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), and propylene carbonate, upon raising the temperature to 120–125°C (reverse‐DA [r‐DA] range) the decross‐linked resins could be dissolved and black solids (mostly fibers) collected by hot filtration over a polytetrafluorethylene filter 19 ; however, the recollected fabric still contained between 5 and 37% resin leftovers. Similar to this study, cross‐linked polyurethanes 20 and Poly(ethylene glycol) diglycidyl ether‐furfurylamine 21 containing DA‐based cross‐links could be dissolved in hot DMF as well as comb‐shaped aromatic polyamide 22 and thermosetting polyketones 23 both cross‐linked by DA chemistry in hot N‐methylpyrrolidone and in hot DMSO, respectively.…”

Section: Introductionsupporting

confidence: 63%

Development of a completely recyclable glass fiber‐reinforced epoxy thermoset composite

Lejeail¹,

Fischer²

2020

J of Applied Polymer Sci

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Stimulated by the growing demand for more sustainable polymer systems, experiments were performed to develop completely recyclable epoxy-based thermoset composite materials involving the separation, recovery, and complete reuse of both components of the composite, the resin and the fibers. In this study, a possibility to design such composites by incorporation of reversible chemistry for dedicated repair and recycling is demonstrated. Relying on Diels-Alder (DA) adducts located on the cross-links between the polymeric chains, uncross-linking the thermoset via the reverse DA reactions becomes possible. The network breaks up at elevated temperatures in shorter segments, which can be solubilized in solvents like acetic acid, butan-1-ol, or toluene. Specific processes for each of these solvents were developed to recover the resin and fibers with virtually unchanged properties. Both components were used in a second manufacturing step to produce recycled composites which display properties comparable with the original composites.

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Section: Introductionsupporting

confidence: 63%

Development of a completely recyclable glass fiber‐reinforced epoxy thermoset composite

Lejeail¹,

Fischer²

2020

J of Applied Polymer Sci

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“…This reversibility is very attractive for healable and/or recyclable thermosets. [133][134][135][136][137] The temperatures of the DA and retro-DA transitions largely depend on the choice of diene and dienophile. In literature, the furan-maleimide system is most often selected due to its suitable temperature profile for reversible bonding.…”

Section: Thermally Reversible Covalent Bondsmentioning

confidence: 99%

“…In literature, the furan-maleimide system is most often selected due to its suitable temperature profile for reversible bonding. 133,134,138 In these systems, the DA reaction takes place at temperatures below 40 C while the retro DA occurs at temperatures above 140 C. By adjusting the molecular weight and ratio of the individual constituents, the mechanical properties and the cross-linking density can be tuned, which in turn alters the viscosity of the retro-DA mixture. This is exemplified by the work of Billiet et al who introduced DA-based thermoreversible 1,2,4-triazoline-3,5-dione groups into polyurethane and polymethacrylate materials, thereby creating a recyclable thermoset with a tunable dynamic behavior.…”

Section: Thermally Reversible Covalent Bondsmentioning

confidence: 99%

A Review on the Potential and Limitations of Recyclable Thermosets for Structural Applications

et al. 2019

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The outstanding performance of conventional thermosets arising from their covalently cross-linked networks directly results in a limited recyclability. The available commercial or close-to-commercial techniques facing this challenge can be divided into mechanical, thermal, and chemical processing. However, these methods typically require a high energy input and do not take the recycling of the thermoset matrix itself into account. Rather, they focus on retrieving the more valuable fibers, fillers, or substrates. To increase the circularity of thermoset products, many academic studies report potential solutions which require a reduced energy input by using degradable linkages or dynamic covalent bonds. However, the majority of these studies have limited potential for industrial implementation. This review aims to bridge the gap between the industrial and academic developments by focusing on those which are most relevant from a technological, sustainable and economic point of view. An overview is given of currently used approaches for the recycling of thermoset materials, the development of novel inherently recyclable thermosets and examples of possible applications that could reach the market in the near future.

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“…With regard to step‐growth polymers, both postfunctionalization and functional monomer approaches have been put to use to obtain a range of azido‐functionalized aliphatic and aromatic polymers. The prominent examples of such polymeric systems include polycarbonates, polyesters, polyurethanes, polyamides, poly(ether sulfone)s, and poly(ether ether ketone)s . As far as functional monomer approach is concerned, most of the reports deal with aliphatic polymers and relatively lesser attention has been paid to monomers suitable for the synthesis of aromatic step‐growth polymers …”

Section: Introductionmentioning

confidence: 99%

A new cardo bisphenol monomer containing pendant azido group and the resulting aromatic polyesters

Maher

Nagane

Jadhav

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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Expanding on our strategy to synthesize aromatic stepgrowth polymers containing pendant clickable azido groups via functional monomer approach, we have now designed and synthesized a new cardo bisphenol, viz., 2-(2-azidoethyl)-3, 3-bis(4-hydroxyphenyl) isoindolin-1-one (PPH-N 3 ). PPH-N 3 was conveniently synthesized starting from commercially available phenolphthalein by a three-step route in an overall yield of 65% using simple organic transformations. Aromatic (co)polyesters bearing pendant azido groups were synthesized by low-temperature solution polycondensation of PPH-N 3 or different molar ratios of PPH-N 3 and bisphenol-A (BPA) with aromatic diacid chlorides in dry dichloromethane in the presence of triethylamine (TEA) as a base. The formation of medium to reasonably high-molecular-weight (co)polyesters was evidenced from intrinsic viscosity and number-average molecular-weight measurements that were in the range 0.52-0.85 dL/g and 16,700-28,200, respectively. Tough, transparent, and flexible films could be cast from chloroform solutions of these (co)polyesters. (Co)polyesters were characterized using FTIR, 1 H NMR, 13 C NMR spectroscopy, XRD, and TGA. The thermal curing reaction of (co)polyesters involving decomposition of azido groups was studied by DSC analysis. The chemical modification of a representative copolyester containing pendant azido groups was carried out quantitatively using catalyst-free azide-maleimide cycloaddition reaction with two maleimides, namely, Nmethylmaleimide and N-hexylmaleimide.Additional supporting information may be found in the online version of this article.

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Comb-shaped aromatic polyamide cross-linked by Diels-Alder chemistry: Towards recyclable and high-performance thermosets

Cited by 33 publications

References 51 publications

Development of a completely recyclable glass fiber‐reinforced epoxy thermoset composite

Development of a completely recyclable glass fiber‐reinforced epoxy thermoset composite

A Review on the Potential and Limitations of Recyclable Thermosets for Structural Applications

A new cardo bisphenol monomer containing pendant azido group and the resulting aromatic polyesters

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