Extraction of Oligomers From Poly(ethylene terephthalate) by Microwave-assisted Extraction

Costley, Claire T.; Dean, John R.; Newton, Ian D.; Carroll, John

doi:10.1039/a608423k

Cited by 35 publications

(14 citation statements)

References 5 publications

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“…Low temperatures (<60 °C) resulted in poor polymer recovery (less than 1%). As reported in other MAE studies concerning polymers (Mar-cato and Vianello, 2000; Costley et al, 1997), temperature had the most significant influence on yield (p < 0.0001) with higher temperatures clearly improving results ( Fig. 1 and Table 1).…”

Section: Yieldsupporting

confidence: 66%

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Sousa

Alves

Morais

et al. 2010

Bioresource Technology

116

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A B S T R A C TMicrowave-assisted extraction (MAE) of agar from Gracilaria vermiculophylla, produced in an integrated multitrophic aquaculture (IMTA) system, from Ria de Aveiro (northwestern Portugal), was tested and optimized using response surface methodology. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the physical and chemical proper-ties of agar (yield, gel strength, gelling and melting temperatures, as well as, sulphate and 3,6-anhydro-L-galactose contents) was evaluated in a 2 4 orthogonal composite design. The quality of the extracted agar compared favorably with the attained using traditional extraction (2 h at 85 °C) while reducing drasti-cally extraction time, solvent consumption and waste disposal requirements. Agar MAE optimum results were: an yield of 14.4 ± 0.4%, a gel strength of 1331 ± 51 g/cm 2 , 40.7 ± 0.2 °C gelling temperature, 93.1 ± 0.5 °C melting temperature, 1.73 ± 0.13% sulfate content and 39.4 ± 0.3% 3,6-anhydro-L-galactose content. Furthermore, this study suggests the feasibility of the exploitation of G. vermiculophylla grew in IMTA systems for agar production.

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Section: Yieldsupporting

confidence: 66%

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Sousa

Alves

Morais

et al. 2010

Bioresource Technology

116

View full text Add to dashboard Cite

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“…[38,105] With MAE at 48°C for 20 min Nielson [105] obtained recoveries higher than 90%. [38,105] Costley et al [106] used the Soxhlet method to extract cyclic trimer and other low molecular weight oligomers from PET with different solvents (xylene, DCM, acetone, water and hexane) at 140°C for 24 h. The recovery rates were around 60%. [38,106] With MAE, Costley et al [106] were also able to obtain recoveries around 60% at temperatures between 70 and 140°C for 30 to 120 min.…”

Section: Advanced Solvent Extraction Methods: Ultrasonic Extraction Supercritical Fluid Extraction (Sfe) Microwave-assisted Extraction (Mmentioning

confidence: 99%

“…[38,105] Costley et al [106] used the Soxhlet method to extract cyclic trimer and other low molecular weight oligomers from PET with different solvents (xylene, DCM, acetone, water and hexane) at 140°C for 24 h. The recovery rates were around 60%. [38,106] With MAE, Costley et al [106] were also able to obtain recoveries around 60% at temperatures between 70 and 140°C for 30 to 120 min. Microwave assisted extraction is not yet available on the market for plastics, but has been commonly applied in other sectors, such as the agriculture sector.…”

Section: Advanced Solvent Extraction Methods: Ultrasonic Extraction Supercritical Fluid Extraction (Sfe) Microwave-assisted Extraction (Mmentioning

confidence: 99%

Recent Advances in Pre-Treatment of Plastic Packaging Waste

Kol¹,

Roosen²,

Üǧdüler³

et al. 2022

Waste Material Recycling in the Circular Economy - Challenges and Developments

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There is an urgent need to close the loop of plastic waste. One of the main challenges towards plastic packaging waste recycling is the presence of a variety of contaminants. These contaminants include organic residues, additives, labels, inks and also other plastic types that can be present in the waste stream due to missorting or in multimaterial structures (e.g. multilayer films in packaging). In this context, pre-treatment processes are a promising route to tackle the difficulties that are encountered in mechanical and chemical recycling due to these contaminants. This chapter gives better insight on the already existing pre-treatment techniques and on the advances that are being developed and/or optimized in order to achieve closed-loop recycling. Some of these advanced pre-treatments include chemical washing to remove inks (deinking), extraction methods to remove undesired plastic additives and dissolution-based pre-treatments, such as delamination and dissolution-precipitation techniques.

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“…Eles podem ser extraídos do PET usando o extrator Soxhlet em conjunto com solventes como, clorofórmio [56][57][58][59] , dioxano [57,60] , diclorometano e xileno [61] . Entretanto, no processo de síntese, a remoção desses compostos cíclicos não é feita pela indústria [25] , pois não é econômica e nem ambientalmente viável.…”

Section: Degradação Termomecânicaunclassified

Poli(tereftalato de etileno), PET: uma revisão sobre os processos de síntese, mecanismos de degradação e sua reciclagem

2009

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estabilidade hidrolítica devido a presença de anéis aromá-ticos na cadeia principal [1] . Atualmente, o PET é um dos termoplásticos mais produzidos no mundo, alcançando no final da década de 90 uma produção mundial em torno de 2,4 × 10 10 kg. As aplicações do PET são: fibras têxteis (67%), embalagens processadas por injeção-sopro (24%), filmes biorientados (5%) e polímeros de engenharia (4%). O sucesso deste material deve-se à sua excelente relação entre as propriedades mecânicas, térmicas e o custo de produção [2] . Resumo: Apresentamos uma revisão sobre o poli(tereftalato de etileno) enfatizando os processos de síntese e os mecanismos de degradação. Atualmente o Brasil apresenta um dos maiores índices mundiais de reciclagem mecânica deste polímero, correspondendo a um percentual de 53%. O sucesso desse termoplástico na indústria de reciclagem deve-se à sua ampla diversidade de aplicações, desde a indústria têxtil (multifilamento) até as indústrias de alimentos, onde as embalagens recicladas grau alimentício poderão ser misturadas com a resina virgem em diversas proporções e reprocessadas para o uso. Uma abordagem sobre a atual legislação do uso de PET reciclado em contato com alimentos também é mostrada neste trabalho. No processo de síntese do PET realizado em duas ou três etapas, são usados comonômeros e aditivos para otimizar as condições de processamento do material. Entretanto, tanto durante a síntese como no processo de reciclagem, ocorrem reações de degradação (termomecânica e termo-oxidativa) e reações secundárias, formando acetaldeído, oligômeros, e o dietileno glicol. A presença desses "contaminantes" acelera o processo de degradação do polímero, afetando a qualidade do produto final. Introdução Palavras-chave: Poli(tereftalato de etileno), degradação termomecânica, degradação termo-oxidativa, acetaldeído, oligômeros, dietileno glicol. Poly(Ethylene Terephthalate), PET: A Review on the Synthesis Processes, Degradation Mechanisms and its RecyclingAbstract: We present a review on poly(ethylene terephthalate), emphasizing the synthesis processes and the degradation mechanisms. Brazil is currently among the countries that most recycle PET, with 53% of this polymer being mechanically recycled. The success of this thermoplastic in the recycling industry is due to its large diversity of applications, from the textile industry to food packaging, where the food grade recycled packages will be mixed with the pristine resin for reprocessing and use. We also discuss the present legal aspects concerning PET recycling and its use in contact with food. In the synthesis of PET, usually done in two or three steps, several co-monomers and additives are used to optimize the final properties and processing conditions. Additionally, during the synthesis, processing and recycling, several degradation (thermomechanical and thermo-oxidation) and secondary reactions occur, producing acetaldehydes, oligomers and diethyleneglicol. The presence of these "contaminants" accelerates the degradation process of the polymer affecting...

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Extraction of Oligomers From Poly(ethylene terephthalate) by Microwave-assisted Extraction

Cited by 35 publications

References 5 publications

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Recent Advances in Pre-Treatment of Plastic Packaging Waste

Poli(tereftalato de etileno), PET: uma revisão sobre os processos de síntese, mecanismos de degradação e sua reciclagem

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