Identification of polyurethanes by high resolution nuclear magnetic resonance spectrometry

Brame, E. G.; Ferguson, Raymond C.; Thomas, George J.

doi:10.1021/ac60248a004

Cited by 32 publications

(13 citation statements)

References 13 publications

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“…The main resonances shown are near to 172.0 ppm (peaks 1 and 2) attributed to carbonyl from amide and ester groups; approximately near to range of 129.0–150.0 ppm (peak 3 ) due to SMA benzene rings; 39.5 ppm attributed to solvent (DMSO); and the range between 30.0 ppm and 50.0 ppm (peaks b–e ) attributed to saturated carbons. The spectrum shows typical PU and SMA resonances as reported in the literature, together with new amide bonds.…”

Section: Resultssupporting

confidence: 65%

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

Martins

Pereira

Diniz

et al. 2016

J of Applied Polymer Sci

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In this work, the idea of modulating the shape memory properties of polyurethanes by changing their macromolecular architecture through the incorporation of polystyrene-based moieties was investigated. To study these effects, poly(styrene-co-maleic anhydride) (SMA) was incorporated during the synthesis of PU as a potential chain extender. Two sample groups were produced: (i) PU, produced with hydrazine as a chain extender and (ii) PU SMA , produced with the addition of SMA instead of hydrazine. The results suggest that the SMA incorporation in the PU SMA chains occurred by the reaction between NCO groups of the PU and maleic anhydride (MA) of the SMA. The presence of SMA was useful in modulating the structure of PU by reducing the soft segment crystallinity and molar mass. These changes in the structure and macromolecular architecture due to the presence of SMA moieties in PU chains led to pronounced improvements in strength, toughness, and the shape recovery ratio. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44471.

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Section: Resultssupporting

confidence: 65%

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

Martins

Pereira

Diniz

et al. 2016

J of Applied Polymer Sci

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“…NMR study on polyurethane has been shown to be very useful to identify various amide groups,3 for quantitative analysis of polyether compositions,4 to identify the type of polyurethane, to estimate their concentration,5 to study hydrogen bonding with different hard segments and degrees of ionization,6 and for the determination of the number‐average molecular weight ( M n ) of isocyanate‐terminated linear polyurethane 7. Chokki studied the microstructure of polyurethane with 1 H NMR 3, 6, 8.…”

Section: Introductionmentioning

confidence: 99%

Structural investigations of polypropylene glycol (PPG) and isophorone diisocyanate (IPDI)‐based polyurethane prepolymer by 1D and 2D NMR spectroscopy

Prabhakar

Chattopadhyay

Jagadeesh

et al. 2005

J. Polym. Sci. A Polym. Chem.

108

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Polyurethane prepolymers are widely used in reactive hot melt adhesives and moisture cured coatings. NCO-terminated polyurethane of polypropylene glycol (PPG)-1000 and isophoron diisocyanate (IPDI) with an NCO/OH ratio of 1.2:1 were prepared without any catalyst or solvent. 1D and 2D NMR spectroscopy was used for the structural investigation of the synthesized prepolymer. 1 H NMR spectra and dibutylamine back-titration were used to monitor the reaction of isocyanate groups with the hydroxyl function of PPG and to allow a good description of the evaluation of the urethane groups. The data on percentage conversion were crosschecked with 13 C NMR spectroscopy in the urethane zone for the methanol endcapped prepolymer. The observations show a higher reactivity of the secondary NCO group than of the primary group.

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“…Signals at 7.074 and 7.248 ppm conform to the H a and H b of the MDI precursor aromatic ring; the presence of PPG precursor indicated by shifts at 4.992 ppm (CH group) and 1.571–1.119 ppm (signals of CH 3 protons at slightly different chemical environment); and the signals at 3.5–3.2 ppm from the CH 2 protons of the EG precursor. 72,73…”

Section: Results and Discussionmentioning

confidence: 99%

Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution

Kumar

Noor²,

Thakur³

et al. 2019

ACS Omega

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Shape memory polymers (SMPs) are an exciting class of stimuli-responsive smart materials that demonstrate reactive and reversible changes in mechanical property, usually by switching between different states due to external stimuli. We report on the development of a polyurethane-based SMP foam for effective pressure redistribution that demonstrates controllable changes in dynamic pressure redistribution capability at a low transition temperature (∼24 °C)—ideally suited to matching modulations in body contact pressure for dynamic pressure relief (e.g., for alleviation or pressure ulcer effects). The resultant SMP material has been extensively characterized by a series of tests including stress–strain testing, compression testing, dynamic mechanical analysis, optical microscopy, UV–visible absorbance spectroscopy, variable-temperature areal pressure distribution, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic thermogravimetric analysis, and 1H nuclear magnetic resonance spectroscopy. The foam system exhibits high responsivity when tested for plantar pressure modulation with significant potential in pressure ulcers treatment. Efficient pressure redistribution (∼80% reduction in interface pressure), high stress response (∼30% applied stress is stored in fixity and released on recovery), and excellent deformation recovery (∼100%) are demonstrated in addition to significant cycling ability without performance loss. By providing highly effective pressure redistribution and modulation when in contact with the body’s surface, this SMP foam offers novel mechanisms for alleviating the risk of pressure ulcers.

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Identification of polyurethanes by high resolution nuclear magnetic resonance spectrometry

Cited by 32 publications

References 13 publications

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

Structural investigations of polypropylene glycol (PPG) and isophorone diisocyanate (IPDI)‐based polyurethane prepolymer by 1D and 2D NMR spectroscopy

Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution

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