Curing and morphology approaches of polyurethane/poly(ethylene glycol) foam upon poly(lactic acid) addition

Almeida, Débora E. O.; Albuquerque, Ananda Karoline Camelo de; Silva, Ingridy Dayane dos Santos; Ries, Andreas; Wellen, Renate Maria Ramos

doi:10.1002/pat.5699

Cited by 4 publications

(17 citation statements)

References 61 publications

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“…13 The conversion rate presents a bell shape for all compounds with ISO suggesting that the reaction mechanism is autocatalytic, without the need to add external catalysts. 48,49 A similar behavior was observed by Almeida et al 2 during PUs curing with PEG and poly(lactic acid) (PLA). The conversion rate, at high ISO concentrations, smoothly shifts the sigmoids from T p = 123 C to T p = 126 C, respectively, for 50% and 70% ISO.…”

Section: Fourier Transform Infrared Measurementssupporting

confidence: 78%

“…NCO band decreases as the temperature increases and is completely consumed in the compound with 70% ISO, suggesting 100% of conversion at 126 C, while 50% ISO presented a maximum of 99% curing at 192 C. This behavior evidences that ISO accelerates the PUs curing 2. In this work, this correlation will be better understood by means of DSC data.…”

mentioning

confidence: 67%

“…The band at 1114-997 cm À1 is attributed to the aliphatic ether group (C O C), referring to ISO, the raw materials spectra can be seen in Figure S1 (Supplementary Material). 1,2,[34][35][36][37][38][39][40][41][42] Figure 2 displays the spectra for ISOPUs collected at T p (please see information in Table 2). It is verified that only the compound with 70% ISO presented complete curing in Tp, evidenced by the disappearance of NCO band at 2267 cm À1 .…”

Section: Ozawa-flynn-wallmentioning

confidence: 99%

“…43 The disappearance of NCO bands at 2267 cm À1 of 50% and 70% ISO evidences the occurrence of polymerization reactions between (NCO) group of PDI diisocyanate and the flexible hydroxyl groups of polyols (OH) of PEG and ISO, promoting the crosslinks, as shown in Scheme 1. 2,27,44,45 Evaluation of the degree of conversion was carried out considering the modified Beer-Lambert equation; the acquired data are shown in Figure 4. The reference band adopted was that at 2944-2867 cm À1…”

Section: Fourier Transform Infrared Measurementsmentioning

confidence: 99%

“…Aiming at providing a PU with higher thermal stability, isosorbide (ISO) addition was successfully employed, providing reticulation, curing, and variations in the degradation mechanism. 1,2,6 1,4:3,6-Dianhydro-D-sorbitol known as ISO is a bicyclic, bifunctional, and renewable monomer derived from D-sorbitol, obtained through the catalytic hydrogenation of D-glucose from starch and cellulose. ISO has properties such as chirality, thermal stability, non-toxicity, and rigidity, being promising for the thermosetting production.…”

mentioning

confidence: 99%

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Synthesis, curing, and degradation kinetics of polyurethanes based on poly(ethylene glycol), isosorbide, and pentamethylene diisocyanate

Araújo

Barreto

Nicácio

et al. 2023

Polymers for Advanced Techs

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Polyurethane (PU) synthesis based on poly(ethylene glycol) (PEG) with isosorbide (ISO) and pentamethylene diisocyanate (PDI), named (ISOPUs) was carried out targeting PUs from renewable sources. The cross-linked ISOPUs were produced and the details of the curing kinetics were determined via Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). DSC scans displayed exotherms between 100 and 200 C, related to cross-linking. ISO addition accelerated the curing and the maximum curing rate (Cmax), with 91 C and 0.2964 min À1 for the compound with 70% ISO. FTIR spectra confirmed the interaction between OH (ISO/PEG) and NCO (PDI) groups, with total NCO consumption (band at 2267 cm À1 ).Through the thermogravimetric analyses (TGA), the PU/70% ISO presented weight loss at 146 C due to the degradation of ISO. ISOPUs displayed a decreased activation energy (Ea) during curing over a range of 100 to 42 kJ/mol for 0 < α < 5%, as demonstrated using the Friedman model, and higher thermal stability as evidenced through TG analyses. Curing and degradation kinetics were modeled using Friedman (FR), Kissinger-Akahira-Sunose (KAS), and Ozawa-Flynn-Wall (OFW). Overall, ISO accelerated the curing rate and increased the degradation Ea, suggesting high thermal stability for PUs with intermediate ISO contents, that is, 30%-50%. K E Y W O R D S biobased polyurethane, curing and degradation kinetics, Isosorbide, pentamethylene diisocyanate, poly(ethylene glycol) 1 | INTRODUCTION Polyurethanes (PU) based on renewable sources, such as bio-based polyols and diisocyanates are being synthesized with the objective to replace PUs from non-renewable sources, such as petroleum, and to reduce the use of toxic isocyanates. The synthesis of bio-based PUs from alternative resources, such as glucose has been growing considerably due to its potential to modify the mechanisms of curing and degradation, providing greater chemical, and physical stability. 1-4 In this context, Wang et al. 5 successfully cross-linked thermosetting PUs through the reaction of a bio-based diol with a monocyclic acetal structure and a trifunctional isocyanate reinforced with carbon fibers.The resulting material presented higher performance for application in the automotive, aerospace, and sports equipment industries.Polyurethanes synthesis takes place through urethane bonds by the polymerization of flexible segments (polyether or polyester), known as polyols, which have one or more OH groups, and rigid segments (diisocyanates) which have two or more NCO groups.

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Section: Fourier Transform Infrared Measurementssupporting

confidence: 78%

mentioning

confidence: 67%

Section: Ozawa-flynn-wallmentioning

confidence: 99%

Section: Fourier Transform Infrared Measurementsmentioning

confidence: 99%

mentioning

confidence: 99%

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Synthesis, curing, and degradation kinetics of polyurethanes based on poly(ethylene glycol), isosorbide, and pentamethylene diisocyanate

Araújo

Barreto

Nicácio

et al. 2023

Polymers for Advanced Techs

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Insights on the processing and thermal degradation kinetics of PA6/PE‐g‐AA blends

Araújo,

Franco,

Barreto

et al. 2024

J of Applied Polymer Sci

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Blends of polyamide 6 (PA6) and polyethylene‐grafted acrylic acid (PE‐g‐AA) in contents 90/10, 80/20, and 70/30 were processed in a torque rheometer. Fourier transform infrared spectroscopy spectra showed secondary hydrogen bond interactions between COOH (PE‐g‐AA) and NCOH (PA6) groups. Addition of PE‐g‐AA did not promote significant changes in the thermal stability of the blends, as evidenced in the torque curves and thermogravimetric plots, which showed weight loss in a single stage for PA6 and PE‐g‐AA, with T0.01 343 and 409°C, and predominant release of CO2, according to thermogravimetric analysis coupled to infrared spectra. The degradation kinetics were adequately modeled using Friedman, Ozawa—Flynn—Wall, and Vyazovkin, with R2 > 0.99, showing a higher value for PE‐g‐AA, occurring in a complex way with three competitive degradation mechanisms, F1, R3, and An.

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Biocomposites based on poly(lactic acid)/Aloe Vera/Priplast. Effects of UVA radiation on the crystallization

Nicácio

Albuquerque

Dantas

et al. 2023

Polymers for Advanced Techs

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Biocomposites based on poly(lactic acid) (PLA), Aloe Vera (AV), and Priplast (Pr), were produced with AV and Pr levels of 5% and 10%, and submitted to UVA radiation for a time interval up to 28 days. Chemical changes were investigated using Fourier transform infrared spectroscopy (FTIR) and the thermal behavior was elucidated using differential scanning calorimetry (DSC); the non‐isothermal crystallization kinetics was modeled using the Pseudo‐Avrami model. FTIR spectra evidenced the formation of chromophore groups resulting from the photodegradation, which it was less intense in biocomposites with 10% Pr. AV addition promoted the cold crystallization, whereas the crystallization rate () displayed higher values for PLA/10%AV, with slight increases in the degree of crystallinity (Xc); while Pr addition decreased the Xc and of PLA, and protected it more intensely against the photodegradation effects. Pseudo‐Avrami model presented R2 ≥ 0.9909 and a low discrepancy between experimental and theoretical data, being adequate to describe the cold crystallization of PLA biocomposites. Summing up, AV and Pr addition protect PLA against the harmful effects of photodegradation, with AV subtly interfering in the crystalline parameters while Pr provides greater amorphicity to PLA biocomposites.

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Curing and morphology approaches of polyurethane/poly(ethylene glycol) foam upon poly(lactic acid) addition

Cited by 4 publications

References 61 publications

Synthesis, curing, and degradation kinetics of polyurethanes based on poly(ethylene glycol), isosorbide, and pentamethylene diisocyanate

Synthesis, curing, and degradation kinetics of polyurethanes based on poly(ethylene glycol), isosorbide, and pentamethylene diisocyanate

Insights on the processing and thermal degradation kinetics of PA6/PE‐g‐AA blends

Biocomposites based on poly(lactic acid)/Aloe Vera/Priplast. Effects of UVA radiation on the crystallization

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