Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Abstract

Hydrodynamic and optical methods were applied to study conformational and physical properties of hyperbranched pyridylphenylene polymers in dilute solutions. The samples were synthesized using Diels–Alder polycyclocondensation. It was demonstrated that hydrodynamic properties of the studied macromolecules were typical for compact non‐percolated spheres. Optical and electro‐optical methods revealed information regarding the shape and asymmetry of the macromolecules (p ≈ 1.4). The contributions of optical shape effect to the observed flow birefringence of polypyridylphenylene solutions and intrinsic anisotropy of polarizability were evaluated and analysed. It was shown that varying the polymer composition (i.e. the degree of branching) caused considerable changes in the anisotropy of optical polarizability of the polymers. Dramatic difference of the electro‐optical properties in non‐polar (toluene) and polar (tetrachloroethane) solvents was found; this difference was related to the orientational correlation of polar solvent molecules with respect to the macromolecules. Dynamic properties were studied by non‐equilibrium electric birefringence which had a reasonable agreement with the dimensions estimated from hydrodynamic data. © 2016 Society of Chemical Industry

Diels–Alder Hyperbranched Pyridylphenylene Polymer Fractions as Alternatives to Dendrimers

“…It is worth noticing that such a comparison of the essential hydrodynamic characteristic made by completely different techniques represents a fundamental task of establishing the intercorrelation of the used methods, especially keeping in mind the AUC reaching the lower limit of molecular mass resolution close to 1000 g mol –1 . In regard to the synthesized polymers (HBPPP1 and HBPPP2), their molecular masses correlate well with earlier studied systems and sedimentation coefficient distributions (Figure S5) resembled ones, which were resolved earlier …”

“…Furthermore, the determination of s 0 and ( f / f s p h ) 0 becomes possible with implementation of absorbance optics, especially while studying pyridylphenylene systems possessing very high absorbance properties. This, in turn, allows studying superdilute solutions with concentrations 3 order of magnitude lower than, for example, in viscometry or DLS measurements . As mentioned above, the D value may be extracted in some cases from the frictional ratio calculated by Sedfit program: where k B is the Boltzmann constant, T is the absolute temperature, υ̅ is the partial specific volume, and ρ 0 and η 0 are the solvent density and viscosity, respectively …”

“Hard” Sphere Behavior of “Soft”, Globular-like, Hyperbranched Polyglycerols – Extensive Molecular Hydrodynamic and Light Scattering Studies

“…The statistical "density" of the A 0 values is reflected by the color intensity in Figure 4 (see the "density" bar) and shows that the majority of the experimental values of A 0 calculated over the entire set of the available literature data are, as a rule of thumb, found to be A 0 = (2.6 ± 0.4) × 10 −10 [g cm 2 s −2 K −1 mol −1/3 ]. 18,23,29,31,32,57,[60][61][62]64 Up to now, we believe that this is the most completed experimental value for the basically all-inclusive family of branched polymer systems. An experimental error of ±0.4 corresponds to an approximately 20% error of the sample molar masses.…”

“…, A 0 = 2.914 . A more general overview on the variation of the hydrodynamic invariants for various, differently branched, both synthetic and natural polymer macromolecules from available literature data being sufficient to calculate the A 0 values, is shown in Figure . ,,,,,− …”

Influence of external and self‐emulsifying sizing agent on the properties of carbon fiber reinforced polyamide composites

“…To meet this technical and social demand, the carbon fiber reinforced plastics (CFRPs) have been developed and used to replace traditional materials. CFRPs exhibit low weight, relatively good mechanical properties, highly resistance to deformation and to both acid and alkaline corrosion . Thermoset plastics have been widely used as the matrix for CRFPs; however, the recycling is the biggest problem for these composites.…”