Properties of aliphatic hyperbranched polyesters in dilute solutions

Autor(en): Vukovic, Jasna
Lechner, Manfred D.
Jovanovic, Slobodan
Stichwörter: aliphatic hyperbranched polyesters; BEHAVIOR; Chemistry; Chemistry, Multidisciplinary; DENDRIMERS; dilute solutions; GPC; INTRINSIC-VISCOSITY; limiting viscosity number; MACROMOLECULES; MOLECULES; POLYMERS; TOPOLOGY
Erscheinungsdatum: 2007
Volumen: 72
Ausgabe: 12
Startseite: 1493
Seitenende: 1506
The results of an investigation of the influence of the synthesis procedure, number of pseudo generations and degree of branching of hydroxy-functional aliphatic hyperbranched polyesters (AHBP) on the values of limiting viscosity number, [eta], hydrodynamic radius, R-eta, molar mass and polydispersity index, Q, are presented in this paper. Two series of AHBP, synthesized from 2,2-bis(hydroxymethyl)propionic acid and di-trimethylolpropane using a pseudo-one-step and a one-step procedure were investigated. The obtained results show that the values of [eta] and R eta for all examined samples are the highest in a 0.7 mass % solution of LiCl in N,N-di-methylacetamide (LiCl/DMAc), which indicates that this solvent is the best from the investigated ones. The values of [eta] in N-methyl-2-pyrrolidinone (NMP) increased up to the sixth pseudo generation, after which a slight decrease occurred as the consequence of the presence of side-reaction products, formed during the synthesis. The appearance of these side-reaction products was also confirmed from the characteristic GPC chromatograms. For the samples of AHBP synthesized using the pseudo-one-step procedure, a good linear dependence between log [eta] and log M-eta was obtained up to the fifth pseudo generation, when LiCl/DMAc. NMP and DMAc were used as solvents. The values of the ``shrinking'' factor, g', were calculated for all investigated AHBPs.
ISSN: 03525139
DOI: 10.2298/JSC0712493V

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