Rheological Properties of Concentrated Solutions of Aliphatic Hyperbranched Polyesters

Abstract

The rheological investigation of concentrated solutions of aliphatic hyperbranched polyesters (AHBP) in N‐methyl‐2‐pyrrolidinon (NMP) is presented. Two series of hydroxy‐functional AHBP were synthesized using pseudo‐one‐step and one‐step procedure. Three commercial (Boltorn®) AHBP were also investigated. In the examined temperature region (10–50 °C), AHBP solutions (c ≤ 45 wt.‐%) exhibited Newtonian behavior. The same was observed for 50 and 55 wt.‐% solutions at T ≥ 40 °C. However, at T < 50 °C, solutions of AHBP of higher concentrations (50 and 55 wt.‐%) showed shear thinning behavior. Values of the flow activation energies were calculated for all examined AHBP. The influence of the procedure for the synthesis, concentration and temperature on rheological behavior of AHBP solutions in NMP is discussed.magnified image

Analysis of dynamic mechanical, thermal and surface properties of poly(urethane-ester-siloxane) networks based on hyperbranched polyester

“…The reasons for that are globular, three-dimensional and compact structure of hyperbranched macromolecules, unique physical and chemical properties and presence of numerous end functional groups, which can be easily modified to adjust the final material for different application requirements [11][12][13]. Czech et al have used Boltorn® HBP of the fourth pseudo generation as crosslinking agents for the synthesis of PU networks based on poly(tetramethylene oxide) [3].…”

Viscoelastic behavior of polyacrylonitrile/dimethyl sulfoxide concentrated solution with water

“…mainly because of its higher melting point and greater carbon yield ([50% of the original precursor mass). [1][2][3][4][5] Conventional spinning processes for PAN precursor fiber include wet and dry-wet spinning, 6,7 both with inherent disadvantages of uneven skin and core structure due to the phase separation process in the coagulation bath, hence greatly weakening the performance of the carbon fiber. To avoid this skin and core disparity, gel spinning is introduced by doping nonsolvent into the PAN spinning solution and/or using a low processing temperature.…”

Entanglement Transition in Hyperbranched Polyether‐Polyols

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