Determination and comparison of molar mass distributions of substituted polystyrenes and block copolymers by using thermal field-flow fractionation, size exclusion chromatography and light scattering

Dammert, Ritva; Jussila, Matti; Vastamäki, Pertti; Riekkola, Marja‐Liisa; Sundholm, Franciska

doi:10.1016/s0032-3861(97)00207-3

Cited by 17 publications

(12 citation statements)

References 17 publications

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“…The molar masses determined with SEC, ThFFF, and light scattering, respectively, are in good agreement. Details of the ThFFF method are discussed in a recent paper . The yields of polymerization in the anionic polymerizations are quite good; the yields of syndiotactic polymers with the titanocene catalyst are reasonable, taking into account the complexity of the reaction.…”

Section: Resultsmentioning

confidence: 99%

Free Volume and Tacticity in Polystyrenes

et al. 1999

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Measurements of the free volume hole size distributions obtained from positron annihilation lifetime spectroscopy (PALS) in relation to the chain tacticity in polystyrene and poly(p-methylstyrene), and in relation to the static free volume distribution in modeled amorphous cells of these polymers are reported. The free volume distribution was estimated using the Voronoi tessellation of space and direct calculations of unoccupied space in modeled amorphous cells of the polystyrenes. The results indicate that the syndiotactic polystyrene and the syndiotactic poly(p-methylstyrene) have broader hole distributions than the more atactic samples. The polystyrenes have a maximum in the free volume hole size distribution at volumes smaller than for the poly(p-methylstyrenes). The calculations indicate the presence of a large portion of holes too small to be detected with positron annihilation. The small holes are related to structural features of the polymer chain itself. The calculated distribution of large holes in the polymers agree satisfactorily with the results from the PALS measurements. The difference is due to the irregular shapes of the holes in the calculated models as compared to the spherical potential wells assumed in the interpretation of results from PALS measurements.

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Section: Resultsmentioning

confidence: 99%

Free Volume and Tacticity in Polystyrenes

et al. 1999

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“…ThFFF has been applied to various copolymer systems since simultaneous separation according to size and chemical composition may take place 6–8. Not much work has been done, however, on the analysis of block copolymers.…”

Section: Introductionmentioning

confidence: 99%

“…AF4 was also used to study the polyelectrolyte complex formation between cationic and anionic copolymers 10. ThFFF was efficiently used for the characterization of various homopolymers,6, 11–20 polymer blends,10, 21 random copolymers,6, 8, 22–25 gel containing samples,26 and polymeric particles 27, 28…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Triblock Copolymer Analysis by Coupled Thermal Field‐Flow Fractionation‐NMR

Aswegen

Hiller

Hehn

et al. 2013

Macromol. Rapid Commun.

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Thermal field-flow fractionation (ThFFF) is used as a novel fractionation technique to investigate the molecular heterogeneity of PB-b-PVP-b-PtBMA triblock copolymers. Such copolymers cause major problems in liquid chromatography due to very strong polar interactions with the stationary phase. ThFFF separates the copolymers with regard to size and/or chemical composition based on the normal and thermal diffusion coefficients. The separation mechanism in ThFFF and the chemical composition of the separated species is elucidated by online (1) H NMR. Based on the compositional analysis and a calibration of the system with the respective homopolymers, the samples are quantified regarding their molar masses, chemical compositions, and microstructures providing comprehensive information on the complex structure of these block copolymers.

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“…One of the most important factors governing polymer properties is the distribution of molecular weights. Classical techniques 1,2 such as viscometry, light scattering, sedimentation and osmometry are widely used to characterize molecular weight distributions, together with newer techniques such as sizeexclusion chromatography, [3][4][5][6][7] field flow fractionation [6][7][8][9][10] and mass spectrometry. [11][12][13] Diffusion data can also provide useful information about molecular weight distributions.…”

Section: Introductionmentioning

confidence: 99%

“…Size-exclusion chromatography [3][4][5][6][7] and mass spectrometry [11][12][13] can provide essentially complete information about polymer molecular weight distributions. No attempt is made here to compete with these powerful techniques.…”

Section: Introductionmentioning

confidence: 99%