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 (2023)

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The anionic polymerisation of styrene-based monomers has been studied very extensively. Polymerisation conditions, such as the solvent, initiator and temperature, have an influence on the properties of the polymers. The interesting properties are, for example, tacticity, molar mass and molar mass distribution. These properties have an effect on the crystallinity and rheology of the polymer. Anionic polymerisation is an excellent method to control the molar mass of the synthesised polymer. When


Since s.e.c. and LS are familiar methods to the polymer chemist, only the principle of ThFFF is presented briefly here. Field-flow fractionation (FFF) is a family of analysis techniques covering a wide range of molecular size from a few thousand Daltons of molar mass to a particle size of ca. 100 μm. Many types of external field can be utilised in FFF including gravitational, centrifugal, electrical and magnetic fields. Also, a thermal gradient and another perpendicular flow can affect the


Styrene (Merck-Schuchardt; > 99%), p-methoxystyrene (Aldrich; > 97%), p-methylstyrene (Aldrich; > 97%) and p-chlorostyrene (Aldrich; > 97%) were dried over CaH2 and purified by fractional distillation in vacuo. The monomers were stored in ampoules sealed with Young's Teflon stopcocks at − 25°C. p-Cyanostyrene was prepared by one-pot reaction of 4-vinylbenzaldehyde with the hydroxylammonium chloride/pyridine/toluene system followed by azeotropic separation of water in 74% yield11, 12, 13.



The repeatabilities of two different FFF runs are listed in Table 1. The calibration accuracy was estimated by calculating the molar mass averages of one individual standard in the standard series used for calibration. The standard deviations, calculated and nominal molar mass averages are in Table 2. The long-term stability of the system was estimated by calculating molar mass averages of one single run using 10 different calibrations carried out during 21 days (Table 3). Since the relative


R. Dammert and M. Jussila thank Neste Ltd. Foundation for financial support. The authors are indebted to E. Aitola for his technical assistance in course of the s.e.c. analysis and to K. Muje for her help in the polymerisations of poly(p-cyanostyrene)s.

Cited by (16)

  • Field-flow fractionation: New and exciting perspectives in polymer analysis

    2016, Progress in Polymer Science

    Citation Excerpt :

    It has been demonstrated that the value of DT is unique for a given homopolymer and it is constant above a certain molar mass [252]. Unfortunately, the low value of DT in water makes it an unfeasible technique for polymer analysis in water as carrier liquid [253]. Therefore, ThFFF is mainly used for simultaneous chemical composition and molar mass analysis of polymers in organic solvents.

    The development of advanced polymeric materials requires state-of-the-art synthesis and molecular characterization protocols. Only the precise knowledge of molecular structure–property correlations allows achieving optimum performance properties of novel materials. The analysis of the molecular composition of a complex polymeric material requires the determination of its molar mass, chemical composition, functionality and molecular topology among other (less important) parameters.

    A number of column-based fractionation methods, including size exclusion chromatography (SEC) and high performance interaction chromatography (HPLC) are the standard techniques for the analysis of complex polymers. These methods work well as long as the molar mass is not too high and/or the macromolecules do not exhibit undesired interactions with the stationary phase (column). Certain polymers form large aggregates or other entities (micelles, liposomes) in solution that typically cannot be analyzed by column-based fractionation methods.

    One alternative for the fractionation of such complex materials is field-flow fractionation (FFF), an open-channel technique which does not use a stationary phase. In FFF, all problems related to the stationary phase such as undesired adsorption, shear degradation of large macromolecules, co-elution of linear and branched macromolecules, can be avoided. Different sub-techniques of FFF render the fractionation of complex polymer systems according to molecular size, chemical composition or molecular topology.

    In this review article, most recent developments of FFF in polymer analysis are addressed. Natural and synthetic polymers, polyolefins and polymeric nanocomposites are embraced. The most important FFF sub-techniques in polymer analysis include asymmetric flow field-flow fractionation (AF4) and thermal field-flow fractionation (ThFFF). Major developments in these very topics since 2008 are critically discussed following a previous review article that summarized earlier work (see Prog. Polym. Sci. 2009; 34: 351–68). The potentials and limitations of the different FFF sub-techniques for polymer analysis are elaborated and most recent methods of hyphenating FFF with other techniques are highlighted.

  • An overview on field-flow fractionation techniques and their applications in the separation and characterization of polymers

    2009, Progress in Polymer Science (Oxford)

    Field-flow fractionation (FFF) is a family of analytical techniques developed specifically for separating and characterizing macromolecules, supramolecular assemblies, colloids and particles. It combines the effects of a laminar flow profile with an exponential concentration profile of analyte components caused by their interactions with a physical field applied perpendicular to the flow of a carrier liquid. FFF is undergoing increasingly widespread use as researchers learn of its potential and versatility. This overview underlines the basic principle and theory behind FFF and reviews recent research efforts incorporating flow and thermal FFF methods to characterize natural, biological, and synthetic polymers. These FFF techniques will be discussed in terms of theory and practice. Selected applications of FFF and their coupling capability with other chromatographic techniques or spectrometric detection for the separation and characterization of polymers in organic and aqueous media are presented.

  • Applications of ACOMP (I)

    2014, Monitoring Polymerization Reactions: From Fundamentals to Applications

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