Chemical structure of the hyperbranched polyester (six repeating units). 

Contexts in source publication

Context 1

... hyperbranched polyester P-OH based on the monomer 4,4-bis(4-hydroxyphenyl)valeric acid was syn- thesized as described above. Hyperbranched polyesters based on this monomer were also studied by Kambouris and Hawker 23 and Voit et al. 24 The molar mass of P 1 -OH was measured as M h n ) 1900 g/mol and M h w ) 5100 g/mol (T g ) 75 °C). The M h n value equals, on average, to approximately six repeating units, as shown in Figure 2, and M h w corresponds to 22 repeating units. However, one has to consider that GPC does not give the absolute molar mass for this highly branched molecule and the molar (18) ...

Context 2

... distribution is broad. The DB was calculated as 50% according to Fréchet et al. 3 Figure 2 shows one possible chemical structure of a hyperbranched polyester macro- molecule which fits a DB of 50% and shows the M h n average six repeating units. However, one has to be aware that each hyperbranched macromolecule varies in the branch- ing sequence (but not DB) forming different isomers and molar masses and, thus, only an example for the structure can be given. Nevertheless, all possible structural isomers should exhibit the same repeating units and the same average content of end groups allowing it to be treated as a chemically uniform material regarding surface activity. The hyperbranched polyester was further modified by functionalizing the OH end groups with alkyl acid chlorides via esterification leading to short alkane chains as end groups. In P-C 1 -51, 51% of the OH groups of the hyperbranched polyester were functionalized, and in P-C 4 - 15, the degree of modification was 15%. The unmodified and modified hyperbranched polyesters were mixed with an oligo(ester diol) (T g ) -39 °C, possible structure shown in Figure 3) at room ...