Specific oligomer recovery behavior from cured unsaturated polyester by superheated steam degradation

Chan, Chi Hoong; Wakisaka, Minato; Nishida, Haruo

doi:10.1016/j.polymdegradstab.2018.12.025

Cited by 8 publications

(4 citation statements)

References 16 publications

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“…Surface-clean CFs can be collected from waste CFRPs at 700-800 • C in 140 min of total process time, excluding cooling time with this methodology, which can also be transferred to a continuous process. Polyesters: Superheated steam recycling has also been implemented on terephthalic and ortho phthalic acid-based co-polyesters crosslinked with styrene to recover oligomers [74]. Since the process was promising, it can be reproduced for co-polyester thermoset composites, to valorise both the reinforcement and the matrix material.…”

Section: Superheated Steam Recyclingmentioning

confidence: 99%

Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review

Podara,

Termine,

Modestou

et al. 2024

Recycling

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This review article gathers the most recent recycling technologies for thermoset and thermoplastic polymers. Results about existing experimental procedures and their effectiveness are presented. For thermoset polymers, the review focuses mainly on fibre-reinforced polymer composites, with an emphasis on epoxy-based systems and carbon/glass fibres as reinforcement, due to the environmental concerns of their end-of-life management. Thermal processes (fluidised bed, pyrolysis) and chemical processes (different types of solvolysis) are discussed. The most recent combined processes (microwave, steam, and ultrasonic assisted techniques) and extraordinary recycling attempts (electrochemical, biological, and with ionic liquids) are analysed. Mechanical recycling that leads to the downgrading of materials is excluded. Insights are also given for the upcycling methodologies that have been implemented until now for the reuse of fibres. As for thermoplastic polymers, the most state-of-the-art recycling approach for the most common polymer matrices is presented, together with the appropriate additivation for matrix upcycling. Mechanical, chemical, and enzymatic recycling processes are described, among others. The use of fibre-reinforced thermoplastic composites is quite new, and thus, the most recent achievements are presented. With all of the above information, this extensive review can serve as a guide for educational purposes, targeting students and technicians in polymers recycling.

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Section: Superheated Steam Recyclingmentioning

confidence: 99%

Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review

Podara,

Termine,

Modestou

et al. 2024

Recycling

View full text Add to dashboard Cite

show abstract

“…Moreover, glycidyl ester epoxy resin is high performing owing to its excellent mechanical properties, heat resistance, and electrical insulation; it possesses low viscosity, high activity, low temperature resistance, and is usually used as a coating, diluent, and large-scale vacuum-infusion device [28]. Current research on the recycling of thermosetting epoxy resins includes mechanical, physical, and chemical methods, where chemical recycling is relatively effective [29,30]. For example, Ahrens et al [31] studied the recycling of thermosetting epoxy used for wind turbine blades and recovered bisphenol A and ber from it.…”

Section: Introductionmentioning

confidence: 99%

Rapid degradation of thermosetting ester epoxies and monomer recovery methods

Hu,

Ma,

Zhou

et al. 2024

Preprint

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The degradation and recycling of waste epoxy resins is an urgent environmental problem, encouraging the use of degradable thermosetting epoxies. In this study, a high-performance thermosetting epoxy resin material that can be easily degraded and recycled was prepared using a low-viscosity and high-activity epoxy monomer, tetrahydrophthalic acid diglycidyl ester. Owing to the breakable ester bond in this epoxy monomer, the thermosetting three-dimensional epoxy cross-linked structure can be rapidly degraded using ethylene glycol at atmospheric pressure. After further depolymerization of the epoxy resin/glycol solution with NaOH, sodium cyclohexene-2-carboxylate was obtained. The sodium salt was acidified, epoxidized, and then re-prepared to obtain the epoxy monomer diglycidyl tetrahydrophthalate. The recycled epoxy monomer possesses the same thermal and mechanical properties as the original epoxy monomer, thus realizing the economic and environmentally friendly degradation and recycling of the thermosetting epoxy resin under mild conditions.

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“…Steam degradation is a promising technology for improving the efficiency of polyester decomposition. The ester bonds in the polyester chains can be cleaved by pyrolysis and hydrolysis, and long-chain structures can be depolymerized into monomers [30]. In our previous study, we reported that steam degradation can promote the hydrolysis of polycarbonate [31], polyimide [32,33], poly(butylene terephthalate) [34], poly(ethylene 2,6-naphthalate) [34], and poly(ethylene terephthalate) [34,35], thereby increasing the production of valuable chemicals.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the steam degradation of poly(lactic acid) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Shao,

Kumagai,

Saito

et al. 2024

Polym J

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The introduction of biodegradable plastics is considered a practical approach to reducing plastic waste accumulation in the environment. Regardless of their biodegradability, plastics should be recycled to effectively utilize and circulate carbon as a resource. Herein, the use of pyrolysis was examined as a method for recycling two common biobased/biodegradable plastics: PLA and PHBH. The pyrolysis of PLA produced lactides (10.7 wt% at 400 °C), but the yield was decreased when the pyrolysis temperature was increased. The presence of steam promoted the hydrolysis of PLA: a steam concentration of 25 vol % increased, the production of lactides at 400 °C to 17.4 wt%. The pyrolysis of PHBH primarily yielded crotonic acid (30.1 wt% at 400 °C), and the yield increased with increasing pyrolysis temperature (71.8 wt% at 800 °C). Steam injection increased the hydrolysis of oligomers, resulting in a 76.1 wt% yield of crotonic acid at 600 °C with a steam concentration of 25 vol %. Thus, we determined that hydrolysis and pyrolysis progress simultaneously under a steam atmosphere, increasing the chemical feedstock recovery from PLA and PHBH. These findings may lead to the proposal of effective degradation methods for treating biobased/biodegradable plastic wastes and ways to maximize the conversion efficiency and target product yields.

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Specific oligomer recovery behavior from cured unsaturated polyester by superheated steam degradation

Cited by 8 publications

References 16 publications

Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review

Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review

Rapid degradation of thermosetting ester epoxies and monomer recovery methods

Characteristics of the steam degradation of poly(lactic acid) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

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