Re-Mendable Polyurethanes

Găină, Constantin; Ursache, Oana; Gaina, Viorica

doi:10.1080/03602559.2010.551392

Cited by 30 publications

(19 citation statements)

References 13 publications

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“…Thus heating at 60°C for 3 days, which was also used for the healing process, was applied for the model reaction. 47) and a furan "ring breathing" 48 signal at 1011 cm −1 (as a shoulder), as well as the simultaneous growth of bands at 970 and 863 cm −1 ascribed to the furan-maleimide cycloadduct, 49 indicating the development of the DA cross-linking reaction over time. 1 clearly shows that the maleimide peak at 6.73 ppm and the furan peaks at 7.33, 6.29 and 6.23 ppm disappeared, whereas the peaks attributed to the DA adduct bond signals appeared at 6.51, 6.44, 5.22, 3.01 and 2.95 ppm.…”

Section: Diels-alder Cross-linking Reactionmentioning

confidence: 98%

Healable shape memory (thio)urethane thermosets

et al. 2015

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Urethane-thiourethane networks combining shape memory properties and the ability to self-heal under mild temperature conditions via Diels-Alder (DA) chemistry were developed. As a result of the shape recovery effect, no external force was needed to bring the fracture surfaces into intimate contact during the healing process. Four network architectures with DA net-points were evaluated. Two systems were composed of either bismaleimidic or bisfuranic semi-crystallized polycaprolactone chains acting as shape memory switching segments (T trans = T m ), whereas the other two networks consisted of bis-/trismaleimidic and trisfuranic monomers and displayed glass transitions for initiating shape recovery behaviour (T trans = T g ). The formation of the DA cross-links, the DA reversibility and shape memory assisted scratch healing of the materials were studied by FTIR and 1 H-NMR spectrometry, differential scanning calorimetry, optical microscopy and tensile measurements. The results indicated that the healing efficiency of scratches depends strongly on the shape recovery ability, without which crack closure and thus the healing reaction could not occur. Two materials were found to feature good shape memory properties as well as efficient scratch-healing capacities, showing mechanical recoveries of 70-80% and the almost complete disappearance of scratches after healing at a mild temperature of 60°C for 1-3 days. These materials could find applications in diverse fields such as self-healing coatings.Scheme 1 Chemical structures of the (thio)urethane multi-maleimide and multi-furan monomers and schematic depiction of the SM networks reversibly cross-linked by the DA reaction. Polymer Chemistry PaperThis journal is

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Section: Diels-alder Cross-linking Reactionmentioning

confidence: 98%

Healable shape memory (thio)urethane thermosets

et al. 2015

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“…Our approach to removable polymer networks is the introduction of chemically labile linkages within cross-linked polymeric networks. We have explored the DA cycloaddition reactions between bismaleimide and furyl monomers or polymers [39][40][41][42]. The mechanical measurements showed a greater elongation at break for obtained polyurethane networks, elongation which can be even nine times higher than that of previously obtained polyurethane networks by Diels-Alder reaction [41].…”

Section: Introductionmentioning

confidence: 99%

Thermally reversible cross-linked poly(ether-urethane)s

Găină¹,

Ursache²,

Gaina³

et al. 2013

Express Polym. Lett.

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Abstract. Cross-linked poly(ether-urethane)s were prepared by Diels-Alder (DA) reaction of the furan-containing poly(ether-urethane) to bismaleimides and showed thermal reversibility evidenced by differential scanning calorimetry and attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR). The furan-containing poly(ether-urethane)s were synthesized by the polyaddition reaction of 1,6-hexamethylene diisocyanate (HMDI) or 4,4!-dibenzyl diisocyanate (DBDI) to poly(tetramethylene ether) glycol (PTMEG having M n = 250, 650, 1000, 1500 and 2000) and 2-[N,N-bis(2-methyl-2-hydroxyethyl)amino]furfuryl as chain extender by the solution prepolymer method. The molar ratio of isocyanate: PTMEG:chain extender varied from 2:1:1 to 4:1:3, which produces a molar concentration of furyl group ranging between 3.65·10 -4 and 1.25·10 -3 mol/g.

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“…Initial exploration on PI involving a bisfuran (BF) and a bismaleimide monomer combination [5,6] opened the way to a stream of publications, by giving an idea of a chemical modification of a DA adduct by aromatization. Various strategies were envisaged for synthesizing or modifying PI structures by exploiting the reactivity of this heterocycle with various dienophiles, by Gaina et al [7][8][9], Sanyal [10,11], Peterson et al [12,13], Liu and Chen [14,15] and Wei and his group [16][17][18][19]. A study of DA polymerization involving furan derivatives and various bismaleimides was recently carried out by Gandini and his group [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Studies on polyimides containing thermoplastic-thermosetting merged segments

Patel

2014

Journal of Polymer Engineering

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Polyimides (PIs) containing thermoplastic and thermosetting merged segments in a chain were developed via Diels-Alder (DA) polymerization of a bisfuran (BF), namely 2,5-bis(furan-2-ylmethylcarbamoyl)terephthalic acid and bismaleimides (BMI1 and BMI2). The intermediate DA polyadducts thus obtained, DAA1 and DAA2, were aromatized and imidized (cyclized) through carboxylic and amide groups in the presence of acetic anhydride, to afford PI1 and PI2. Synthesized DA polyadducts and PIs were characterized by elemental analysis, spectral features, number average molecular weight (Mn), degree of polymerization (Dp) and thermal analysis. Bulk polymerization was also carried out. The obtained bulk polymerization products (BPP1 and BPP2) were characterized by elemental analyses and Fourier transform infrared spectroscopy (FT-IR) analysis. The "in situ" void-free glass fiber reinforced composites GFRC1 and GFRC2 were prepared from the produced system and characterized by chemical, mechanical and electrical analysis. All of the composites depicted good mechanical and electrical properties and good resistance to organic solvents and mineral acids.

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Re-Mendable Polyurethanes

Cited by 30 publications

References 13 publications

Healable shape memory (thio)urethane thermosets

Healable shape memory (thio)urethane thermosets

Thermally reversible cross-linked poly(ether-urethane)s

Studies on polyimides containing thermoplastic-thermosetting merged segments

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