Determination of composition and molecular weight of polyester urethanes by high resolution proton magnetic resonance spectrometry

Yeager, F. W.; Becker, J.

doi:10.1021/ac50014a014

Cited by 15 publications

(6 citation statements)

References 22 publications

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“…Koji et al9 have prepared several types of model compounds for anomalous linkages in polyurethane (branching or crosslinking; allophanate and biuret) and analyzed them with 13 C NMR chemical shifts. Yeager et al10 investigated the chemical structure of polyester–urethane with 1 H NMR. They elucidated the composition and the M n of the polyester moiety in the polyurethane.…”

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.

110

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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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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.

110

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“…The completion of the hydrosilylation reaction was confirmed by the absence of peaks from −CHCH 2 on allyl-tBuPOSS (δ ppm 5.75 and 4.90) and Si–H on hydride-PDMS (δ ppm 4.69) in the final product. 1 H NMR was used to determine the number-average molecular weight ( M N ) of the polymers. − The number of protons in each polymer molecule was determined from the integration of the PDMS peak (δ ppm 0.07) with the integrals calibrated to the end-group protons. The calculated M N values of all of the compounds were obtained from the integration of their 1 H NMR spectra and are given in Table .…”

Section: Resultsmentioning

confidence: 99%

Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

et al. 2015

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A series of dumbbell-shaped nanocomposite materials of poly(dimethylsiloxanes) (PDMSs) and polyhedral oligomeric silsesquioxanes (POSSs) were synthesized through hydrosilylation reactions of allyl-and vinyl-POSS and hydrideterminated PDMS. The chemical structures of the dumbbellshaped materials, so-called POSS-PDMS-POSS triblocks, were characterized by 1 H NMR and FT-IR spectroscopy. The molecular weights of the triblock polymers were determined by gel permeation chromatography (GPC). Their size was analyzed by small-angle neutron scattering (SANS) and pulsed-field gradient stimulated echo (PFG STE) NMR experiments. The impact of POSS on the molecular mobility of the PDMS middle chain was observed by using 1 H spin−spin (T 2 ) relaxation NMR. In contrast to the PDMS melts, the triblocks showed an increase in mobility with increasing molecular weight over the range studied due to the reduced relative concentration of constraints imposed by the end-tethered nanoparticles. The triblock systems were used to compare the impact of tethered nanoparticles on the mobility of the linear component compared to the mobility of the polymer in conventional blended nanocomposites. The tethered nanoparticles were found to provide more reinforcement than physically dispersed particles especially at high molecular weights (low particle concentration). The physical blends showed an apparent percolation threshold behavior.

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“…The system was calibrated with a number of polystyrene standards of known molar mass and low polydispersity. Theoretical molecular weights were estimated using a literature procedure involving 1 H NMR spectroscopy (22). The degree of branching (DB) in the hyperbranched polyesters can be determined by 13 C NMR spectroscopy (23,24).…”

Section: Characterization Of Hyperbranched Polyestersmentioning

confidence: 99%

Effect of aliphatic chain length on the chemical structures of low molecular weight hyperbranched polyesters

Wallis¹,

Bonhomme²,

Fabre³

et al. 2018

E-Polymers

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Low molecular weight hyperbranched (HB) polyesters were synthesized via melt polymerization from trimethylolpropane and three aliphatic dicarboxylic acids, namely, succinic acid (SA), adipic acid (AA) and dodecanedioic acid (DA). The degrees of branching (DBs) ranged between 30% and 75% depending on the monomer ratio. Their DB, cyclic index and terminal index were all determined, indicating that the shorter chain HB polyesters PE-SA and PE-AA showed a greater degree of intramolecular cyclization, compared to the longer aliphatic chains within PE-DA. The HB polyesters form stable colloidal suspensions in buffered aqueous media and were found to be pH responsive. The stability of the colloidal suspensions is enhanced by two factors: (1) increasing the aliphatic chain length and (2) increasing the pH of the solution for the same HB polyester.

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Determination of composition and molecular weight of polyester urethanes by high resolution proton magnetic resonance spectrometry

Cited by 15 publications

References 22 publications

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

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

Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

Effect of aliphatic chain length on the chemical structures of low molecular weight hyperbranched polyesters

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