A relaxation time study of molecular motion in trimethylolpropane triacrylate and trimethylolpropane trimethacrylate

Harrell, J. W.; Ahuja, Sanjay

doi:10.1016/0301-0104(89)87144-7

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…16 T 1 measurements can be used to determine changes in molecular motion caused by polymerization. 17,18 In Figure 4, the value of T 1 decreases, depending upon the correlation time of the local motions that contribute to the relaxation. T 1 increases with temperature and decreases during polymerization.…”

Section: Discussionmentioning

confidence: 99%

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H NMR Imaging and Spectroscopy Studies of the Polymerization of Acrylamide Gels

et al. 1996

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1H nuclear magnetic resonance spectra and images have been acquired during polymerization of a mixture of soluble reactive methacrylamide (monomer) and N,N‘-methylenebisacrylamide (cross-linking molecule). The mixture was polymerized by adding ammonium persulfate (initiator) and tetramethylethylenediamine (accelerator) to form long-chain, cross-linked polymers. Study of the time-varying spin−lattice relaxation times (T 1) during the polymerization was conducted at 25 and 35 °C and the variation of spectra and T 1 with respect to the extent of polymerization was determined. To verify homogeneous polymerization, multidimensional 1H NMR imaging was utilized for in-situ monitoring of the process. The intensities from the images are modeled and the correspondence shows a direct extraction of T 1 data from the images.

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Section: Discussionmentioning

confidence: 99%

“…The measurements of T 1 reveal the effect of polymerization on the motion of the methyl group and the side and main chains , In Figure , the value of T 1 decreases, depending upon the correlation time of the local motions that contribute to the relaxation. T 1 increases with temperature and decreases during polymerization.…”

Section: Discussionmentioning

confidence: 99%

H NMR Imaging and Spectroscopy Studies of the Polymerization of Acrylamide Gels

et al. 1996

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An NMR study of the electron beam‐induced polymerization of trimethylolpropane triacrylate and trimethylolpropane trimethacrylate

Harrell¹,

Choudhury²,

Ahuja³

et al. 1991

J Polym Sci B Polym Phys

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Electron beam‐induced polymerization of trimethylolpropane triacrylate (TMPTA) and its methacrylate analog (TMPTMA) was studied using nuclear magnetic resonance (NMR) relaxation time measurements. Free induction decays (FID) of partially polymerized samples consist of a short Gaussian component and a longer component comprised of a distribution of simple exponentials. The relative intensity of the Gaussian component increases with radiation dose. T1 and T1ρ values were measured as a function of temperature and radiation dose. The relaxation is due primarily to methyl group reorientation at low temperatures, ethyl group reorientation at intermediate temperatures, and whole‐molecule reorientation at high temperatures. In both compounds, the T1 and T1ρ values at the high temperature minima increase with increasing dose, and the minima values can be used to estimate the degree of polymerization. The temperature at which the T1ρ minimum occurs increases with dose, suggesting an increase in the glass transition temperature, Tg, with polymerization. The polymerization appears to have very little effect on the low temperature CH3 reorientation in TMPTA. In TMPTMA the polymerization appears to reduce the mobility of the methacrylate methyl groups.

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A relaxation time study of molecular motions in the glass and crystalline phases of 1,6-hexanediol dimethacrylate

Harrell

Gopalakrishnan

1992

Chemical Physics

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A relaxation time study of molecular motion in trimethylolpropane triacrylate and trimethylolpropane trimethacrylate

Cited by 3 publications

References 9 publications

H NMR Imaging and Spectroscopy Studies of the Polymerization of Acrylamide Gels

H NMR Imaging and Spectroscopy Studies of the Polymerization of Acrylamide Gels

An NMR study of the electron beam‐induced polymerization of trimethylolpropane triacrylate and trimethylolpropane trimethacrylate

A relaxation time study of molecular motions in the glass and crystalline phases of 1,6-hexanediol dimethacrylate

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