Reactive blending and transesterification-induced degradation of isosorbide-based polycarbonate blends

Lai, Wenqin; Wu, Guozhang

doi:10.1016/j.polymdegradstab.2019.02.020

Cited by 19 publications

(11 citation statements)

References 45 publications

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“…The propagation reactions of degradation by attack of the hydroxyl group in excess, as seen in the FTIR spectra for 50% and 70% ISO (Figure 2), often contribute to the degradation of PU and are terminated when the reactive end groups are consumed. 8,60 Therefore, it can be considered that high amounts of ISO reduce the thermal stability of the compounds, despite the high degree of curing for these compounds (50% and 70% ISO) observed in Figure 8B, which start to degrade at low temperatures when compared to PU and ISOPUs with low contents of ISO. The data in Figure 10 were used to calculate and plot ln (dα/dt) versus 1000/T for the FR (Figure 13A), KAS (Figure 13B) and OFW (Figure 13C) models for the 30% ISO, in order to calculate the activation energy of degradation (Ead).…”

Section: Thermogravimetric Analysismentioning

confidence: 98%

“…ISO has been extensively investigated for PUs improvements due to its hydroxyl groups that can be converted into urethane ones when reacting with isocyanate groups. 1,[7][8][9][10][11] The use of ISO in step-growth polymerization of PU based on poly(ethylene glycol) and biobased aliphatic polyisocyanate (PDI-trimer), with a large proportion of the carbon content -70%based on biomass, leads to the synthesis of sustainable bio-based polymers with competitive properties compared to the petroleum sources polymers to produce a three-dimensional reticulation network. 12,13 Literature reports the use of ISO in the synthesis of PU, Hong et al 14 investigated shape memory PUs development; Oprea et al 15 formulated flexible elastomeric PUs.…”

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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: Thermogravimetric Analysismentioning

confidence: 98%

mentioning

confidence: 99%

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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“…The reduction in molecular weight caused by transesteri cation without inhibitor is an unavoidable side effect for polyester processing. In general, ester bond fracture in ester exchange process leads to degradation of polyester molecular chain, which reduces melt strength and mechanical strength [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

High Melt Performance Poly (lactic acid) with Dual Hybrid Long Branching Chains Prepared by Chain Degradation and Restructuring

Yang

Qin

et al. 2023

Preprint

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Long chain branched structure (LCBs) is the critical to upgrade the poly (lactic acid) (PLA) melt performance, while introducing LCBs via chain restructuring by melt transesterification features higher-efficiency, environment-friendly and gel-free properties. However, severe degradation associated with excessive transesterification renders the branching reaction non-dominant, resulting in a significantly narrow processing window for LCBs formation. Herein, a new strategy, dual hybrid branching (DHB), was put forward to overcome the challenges. Specifically, surface-aminated nano-ZnO (SAN-ZnO) was applied as a transesterification accelerant to prepare LCB-PLA via melt transesterification between high molecular weight PLA and low molar mass monomer trimethylolpropane triacrylate (TMPTA) in an internal mixer. Moreover, amidogens on the surface of SAN-ZnO was capable to collect the degraded PLA chains (PLA-COOH) and in situ react with their carboxyl thermal groups via amidation. Benefiting from DHB to facilitate LCBs formation and restrain excessive degradation, the melt performance of PLA, especially the melt strength, was obviously improved to over 37 cN compared with pristine PLA (4 cN), and the cold crystallization occurred earlier owing to the DHB chain structure.

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“…These cause difficulties for the interpenetration of molecular chains of both polymers and resulting in a brittle blends. Therefore, many studies [8][9][10][11][12][13][14][15][16] were carried out to enhance the compatibility of PLA/PC blend which is a key for various end-user applications. In comparison to synthesising a new copolymer to achieve the desired properties that cannot be achieved with the currently available polymers, melting PC and PLA will be a much more practical and cost-effective technology.…”

Section: Introductionmentioning

confidence: 99%

Compatibilization of Poly (lactic acid)/Polycarbonate Blends using Triacetin-mediated Interchange Reactions

Kumar

Hassan²,

Yahya³

et al. 2023

Mal. J. Fund. Appl. Sci.

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There is a strong interest in the use of poly (lactic acid) PLA which is a renewable polymer for environmental sustainability. The aim of the paper is to improve the properties of PLA by blending with polycarbonate (PC) at various ratios using melt blending technique. The effects of two types of triacetin (TA) as compatibilizers and tetra butyl ammonium tetraphenylborate (TBATPB) as catalyst were investigated. Mechanical, thermal and morphological properties of the PLA/PC blends were examined. The addition of both triacetin (2022 type, 5 wt%) with catalyst (0.2 wt%) in 50PLA/50PC blends showed good improvement in modulus and elongation at break. The Young’s modulus, flexural modulus and elongation at break increased by 280MPa, 238MPa and 94% respectively compared to uncompatibilzed 50PLA/50PC blend. It was depicted that transesterification reaction can take place only in the presence of compatibilizers; however, the addition of the catalyst accelerates the reaction. Dynamic mechanical analysis revealed a new peak attributed to the glass transition temperature (Tg) of the PLA-PC copolymer at a temperature (~ 110 °C) higher than Tg of typical PLA and lower than the Tg of typical PC. It can be concluded that the addition of triacetin and catalyst results in the overall best mechanical properties, thereby confirming the synergistic action promoted the transesterification reaction between PLA and PC promoting the compatibility of the PLA/PC system.

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Reactive blending and transesterification-induced degradation of isosorbide-based polycarbonate blends

Cited by 19 publications

References 45 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

High Melt Performance Poly (lactic acid) with Dual Hybrid Long Branching Chains Prepared by Chain Degradation and Restructuring

Compatibilization of Poly (lactic acid)/Polycarbonate Blends using Triacetin-mediated Interchange Reactions

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