Influence of hyperbranched polyesters on the surface tension of polyols.
The influence of hyperbranched polyesters with different functional end groups on the surface tension of mixtures with an oligo(ester diol) was investigated. The temperature dependence of the surface tension of the pure components and of the mixtures was measured by a modified Wilhelmy balance technique. The results indicate that the surface tension of the pure hyperbranched polyesters strongly depends on the functionality of the end groups. The functionalization of the hydroxyl end groups by short alkyl chains (methyl, tert-butyl) reduced the surface tension depending on the degree of substitution. The surface tension of the mixtures with the hydroxyl-terminated hyperbranched polyester was slightly increased at higher concentrations of the hyperbranched polymer compared to the surface tension of the pure ester diol. On the other hand, the surface tension of mixtures could be considerably decreased using 1% of hyperbranched polyester polyols partially substituted with short alkyl chains. In that case, the modified hyperbranched polyesters act as surface active agents. On the molecular level, the enrichment of the modified hyperbranched polyester in the surface region was proven by X-ray photoelectron spectroscopy measurements.
Ziemer
Antje
A
Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, 01069 Dresden, Germany.
Azizi
Mazen
M
Pleul
Dieter
D
Simon
Frank
F
Michel
Stefan
S
Kreitschmann
Mirko
M
Kierkus
Paul
P
Voit
Brigitte
B
Grundke
Karina
K
D015394:Molecular Structure; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013500:Surface Tension; D013696:Temperature; D013997:Time Factors
D011091:Polyesters; D011108:Polymers; C024617:polyol