Estimation and characterization of polyester oligomers

Shukla, S. R.; Kulkarni, Kiran

doi:10.1002/(sici)1097-4628(19991121)74:8<1987::aid-app12>3.0.co;2-g

Cited by 17 publications

(15 citation statements)

References 10 publications

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“…The degree of conversion from CBT oligomers to pCBT according to Eqn (3) is 97.9% for pCBT, which is in accordance with other published results 1, 6, 9. A 100% complete conversion cannot be achieved because polyesters are known to undergo ring–chain equilibrium reactions either in the melt or in solution and oligomers are present in concentrations of about 1–3 wt% 1–3, 29–32…”

Section: Resultssupporting

confidence: 90%

“…The remaining CBT oligomers after polymerization may be dissolved in THF and thus may be removed from the bulk material by solvent extraction. Cyclic oligomers in polyesters affect processing as well as material properties,29–32 and therefore efforts are made to remove them from the bulk polymer by various methods. Vermylen et al 30 prepared a cyclic‐oligomer‐free poly(ethylene terephthalate) (PET) by solvent extraction in a Kumagawa extractor using 1,4‐dioxane as the boiling solvent.…”

Section: Resultsmentioning

confidence: 99%

“…Vermylen et al 30 prepared a cyclic‐oligomer‐free poly(ethylene terephthalate) (PET) by solvent extraction in a Kumagawa extractor using 1,4‐dioxane as the boiling solvent. Also Shukla and Kulkarni31 extracted cyclic oligomers from PET using extraction and dissolution methods. Although the oligomer peak in the GPC trace is not present, a prominent peak with a corresponding molecular weight of 73.4 g mol −1 is detected, obviously belonging to THF (72.11 g mol −1 ) and thus demonstrating its presence in the polymer after compression moulding.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran

Abt¹,

Sánchez‐Soto²,

Illescas³

et al. 2010

Polymer International

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A new method of toughening polymerized cyclic butylene terephthalate (pCBT) with tetrahydrofuran (THF) is proposed. The\ud pCBT was prepared by in situ ring-opening polymerization of a commercial cyclic butylene terephthalate, a cyclic form of\ud poly(butylene terephthalate), in the presence of THF. In comparison to conventionally polymerized pCBT, the resultant material\ud was found to be ductile, showing a strain at break of well above 100% in tensile tests. Other matrix properties, such as tensile\ud modulus, tensile strength and glass transition temperature, were not significantly altered by the addition of THF. It was found\ud that the presence of THF enhanced the polymerization reaction, resulting in an increased molecular weight and a narrowed\ud molecularweightdistribution. Moreover, remaining oligomers after polymerization were extractedby the THF anda toughened\ud oligomer-free pCBT was obtained. The influence of time and temperature on the long-time toughening action of THF was\ud studied. The results showed that samples became brittle after 3months when subjected to a temperature of 80 ◦C, resulting in\ud a reduction of the toughening action.\ud c 2010 Society of Chemical IndustryPeer ReviewedPostprint (published version

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran

Abt¹,

Sánchez‐Soto²,

Illescas³

et al. 2010

Polymer International

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show abstract

“…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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“…[13,14,15,16,17] Not only can these be a source of volatiles that can condense and fall back onto the film surface as a surface dusty contaminant but they can also be a cause of poor adhesion. [13,14,15,16,17] Not only can these be a source of volatiles that can condense and fall back onto the film surface as a surface dusty contaminant but they can also be a cause of poor adhesion.…”

Section: Oligomersmentioning

confidence: 99%

Substrates—Surface Quality, Cleaning—Adhesion and Adhesion Testing

Bishop¹

2007

Vacuum Deposition Onto Webs, Films, and Foils

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Estimation and characterization of polyester oligomers

Cited by 17 publications

References 10 publications

Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran

Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran

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

Substrates—Surface Quality, Cleaning—Adhesion and Adhesion Testing

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