Anomaly in the Molecular Weight Dependence of Surface Tension of Molten Polyethers and Polyesters. Evidence of Chain Folding?

Lipatov, Yu.S.; Lobodina, Alla P.; Maistruk, V. K.; Privalko, V. P.; Feinerman, A. E.

doi:10.1021/ma60038a020

Cited by 12 publications

(2 citation statements)

References 3 publications

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“…This effect, in turn, is connected to the transition from almost rigid short oligomeric molecules to molecules possessing a definite flexibility. M crit manifested itself also in the dependencies of the surface tension of the oligoethers on the molecular mass 19, 20. Instead of a linear growth of the surface tension with the molecular mass, at M crit there was observed a minimum attributed to the reduced packing of the macromolecules in the region of the transition from rigid to semiflexible chains.…”

Section: Resultsmentioning

confidence: 99%

Free volume distribution in crosslinked polyurethanes

Feinerman

Lipatov

2000

J. Polym. Sci. B Polym. Phys.

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Free volume distribution was studied for polyurethane networks differing in the molecular mass of oligopropylene glycol taken in the synthesis. To estimate the free volume distribution experimentally, inversed gel chromatography was proposed. The integral and differential distribution of the free volume was constructed. Experimental data for the crosslinked polyurethanes showed the difference in the value of the free volume and its distribution due to the varied packing of oligomeric chains in the regions of the molecular mass below and above the critical molecular mass of entanglements. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 899–905, 2000

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Section: Resultsmentioning

confidence: 99%

Free volume distribution in crosslinked polyurethanes

Feinerman

Lipatov

2000

J. Polym. Sci. B Polym. Phys.

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“…The formation of aggregates implies some kind of fractionation in solution, because the fractions with less solubility should aggregate first (16). In such a case one should expect that, because of the preferential adsorption of aggregates, the amount of high molecular fractions adsorbed near C * was higher as compared with adsorption from dilute solutions.…”

Section: Resultsmentioning

confidence: 99%

Polydispersity Effect on the Adsorption of Polymer Mixtures

Lipatov

Feinerman

Todosijchuk

et al. 2000

Journal of Colloid and Interface Science

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Carbon‐13 nuclear magnetic resonance spectroscopy of poly(ethy1ene glycol)

Lindberg

Sirén

Rahkamaa

et al. 1976

Angew. Makromol. Chem.

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ZntroductionSeveial reports have been published concerning the discontinuities of the physical and dynamic properties of poly(ethy1ene glycol) (PEG) with an average molecular weight range of R,S 1OOOO. Thus, spin-labelling relaxation measurements revealed an anomalously high activation energy value in the melting region of PEG with M,=1550'. Surface tension (y) measurements of PEG as a function of molecular weight (M,) gave a minimum y-value at My= 1300 (T=353 K)2. Also the viscoelastic behaviour of PEG is anomalous in the R, range of -20003. These results have been explained in terms of the onset of chain f~l d i n g~-~ and of the end group effect7.'The use of proton decoupled carbon-13 nuclear magnetic resonance spectra ( 13C-{ 'H}NMR) in the elucidation of PEG and PEG-maleic anhydride copolymer microstructures is documented *. Our earlier studies of PEG dynamics by spin-labelling technique were concentrated nearest upon the end group and interphase effects 1*7. By means of carbon-I3 relaxation measurements it is also possible to get infdrmation about the backbone dynamics of PEG chains. Therefore we have studied the change of carbon-13 spin lattice relaxation times (TI) of PEG melts as a function of R, (R,=600-20000) to get a clearer view about the PEG chain dynamics in this molecular weight region.

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Anomaly in the Molecular Weight Dependence of Surface Tension of Molten Polyethers and Polyesters. Evidence of Chain Folding?

Cited by 12 publications

References 3 publications

Free volume distribution in crosslinked polyurethanes

Free volume distribution in crosslinked polyurethanes

Polydispersity Effect on the Adsorption of Polymer Mixtures

Carbon‐13 nuclear magnetic resonance spectroscopy of poly(ethy1ene glycol)

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