Chemical recycling of unsaturated polyester resin and its composites via selective cleavage of the ester bond

Wang, Yuqi; Cui, Xiaojing; Yang, Qiqi; Deng, Tiansheng; Wang, Yingxiong; Yang, Yongxing; Jia, Shiyu; Qin, Zhangfeng; Hou, Xun

doi:10.1039/c5gc01048a

Cited by 86 publications

(24 citation statements)

References 39 publications

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“…The recent development of novel polymers with dynamic exchange reaction (ER) enables thermosets dissolution under mild conditions. [6][7][8][9][10][11][12] The dynamic bonds activated by a specic stimulus or chemicals lead to network rearrangement and selective bond cleavage. [13][14][15][16] These dynamic polymers have the desirable attributes of conventional thermosets, but also have more attractive attributes, such as self-healing and reprocessing of thermosets.…”

Section: Introductionmentioning

confidence: 99%

Dissolution of epoxy thermosets via mild alcoholysis: the mechanism and kinetics study

et al. 2018

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Section: Introductionmentioning

confidence: 99%

Dissolution of epoxy thermosets via mild alcoholysis: the mechanism and kinetics study

et al. 2018

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“…Increased awareness of environmental impact from plastics has intensied the research into bio-based and recyclable polymeric materials. [1][2][3][4] A class of plastics showing strong potential is polyesters. Polyesters are challenged in high-temperature environments due to their vulnerability to thermally induced mechanical changes which limits service life.…”

Section: Introductionmentioning

confidence: 99%

Accelerated physical ageing of poly(1,4-cyclohexylenedimethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate)

et al. 2019

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Successfully evaluating plastic lifetime requires understanding of the relationships between polymer dynamics and mechanical performance as a function of thermal ageing. The relatively high T g (T g ¼ 110 C) of poly(1,4-cyclohexylenedimethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate) (PCTT) renders it useful as a substituent for PET in higher temperature applications. This work links thermal ageing and mechanical performance of a commercial PCTT plastic after exposure to 40-80 C for up to 2950 h. No chemical or conformational changes were found while pronounced physical ageing, measured as enthalpic relaxation, caused yield hardening (28% increase in yield strength) and embrittlement (80% decrease in toughness). Enthalpic relaxation increased with temperature and time to 3.8 J g À1 and correlated to the determined toughness and yield strength. Finally, a 9% increase in Young's modulus was observed independent of temperature and with no correlation to enthalpic relaxation. Enthalpic relaxation followed Vogel-Fulcher-Tammann behaviour, while yield strength and charpy v-notch toughness followed Arrhenius behaviour enabling prediction of the different properties with time and temperature. View Article Onlinewhere M C and M T are the molecular weights of the CHDM and TMCD repeating units (both 274 g mol À1 ), respectively. TMCD/CHDM ratio (f T/C ) was calculated from the carbonyl 13 C-NMR CHDM (1, 167.8 ppm) and TMCD (7, 168.4 ppm) peaks as given in eqn (4):This journal is

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“…The chemical recovery of anhydride‐cured epoxy thermosets typically included organic solvolysis and hydrolysis [28–40] . Due to the lipophilic wettability of epoxy thermosets, it is more efficient to perform degradation in organic solvents, mostly alcohols, with the assistance of catalysts, such as zinc acetate, 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD), and others [33–38] .…”

Section: Introductionmentioning

confidence: 99%

“…On the one hand, it makes the hydrolysis product easily separated from the aqueous system due to its insolubility; on the other hand, it makes the hydrolysis process more difficult due to nonwettability of the epoxy thermoset to the aqueous reactants. Therefore, harsh conditions, such as higher temperature (190–220 °C) and longer time (5–9 h) are always required [29–31] …”

Section: Introductionmentioning

confidence: 99%

Multicycling of Epoxy Thermoset Through a Two‐Step Strategy of Alcoholysis and Hydrolysis using a Self‐Separating Catalysis System

Wang

Feng

et al. 2021

ChemSusChem

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Plastic has now become a contradiction between civilization and pollution that human society has to resolve. The recycling of thermosetting plastics in waste plastics is a huge challenge since they are difficult to remold like thermoplastic plastics due to their high crosslinking density. Here, a new strategy was developed to achieve multicycling of anhydride‐cured epoxy thermosets. The process consisted of mild and high‐efficiency alcoholysis catalyzed by potassium phosphate/low‐boiling alcohol system, and subsequent fast hydrolysis to obtain degradation products rich of carboxyl groups. The degradation products were reused as curing agent to prepare new anhydride‐cured epoxy thermosets without sacrifice of high strength and stability. Moreover, the new epoxy thermosets could still be repeatedly recycled using the same protocol. The insolubility of potassium phosphate in ethanol at room temperature made the separation and reuse of the catalyst more convenient. The use of low‐boiling alcohol not only allowed high‐efficiency degradation but also enabled easy separation from the degradation products. The excellent degradation performance was attributed to the improved swelling of the thermoset and the increased solubility of potassium phosphate induced by small amounts of water in the alcohol. This research provides a recycling method that can reintegrate thermoset waste plastics into remodeling ones under the background of circular economy.

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Chemical recycling of unsaturated polyester resin and its composites via selective cleavage of the ester bond

Abstract: Unsaturated polyester resin (UPR) is recycled by using the AlCl3/CH3COOH degradation system via selectively cleaving the ester bond.

Cited by 86 publications

References 39 publications

Dissolution of epoxy thermosets via mild alcoholysis: the mechanism and kinetics study

Dissolution of epoxy thermosets via mild alcoholysis: the mechanism and kinetics study

Accelerated physical ageing of poly(1,4-cyclohexylenedimethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate)

Multicycling of Epoxy Thermoset Through a Two‐Step Strategy of Alcoholysis and Hydrolysis using a Self‐Separating Catalysis System

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