Molecular Structure Characterization of Hyperbranched Polyesteramides

Abstract

The molecular structure of a series of hyperbranched polyesteramides was studied using size exclusion chromatography (SEC), mass spectrometry (MS) and small-angle neutron scattering (SANS). Products with increasing molecular mass were obtained through the polycondensation of in situ produced AB 2-like monomeric units. Electrospray ionization MS indicates that narrow SEC fractions consist of different isomers, the number of which increases with molecular mass. Molecular mass moments and polydispersity numbers increase with polycondensation degree. The SANS measurements and SEC-DV data yield values for the polymers fractal dimension, which can be rationalized in the framework of percolation theory that originally was designed for randomly branched polymers. Randomly branched polymer behavior in this particular case possibly results from a side reaction involving reactivity among B-end groups.

Hyperbranched Polymers: Structure of Hyperbranched Polyglycerol and Amphiphilic Poly(glycerol ester)s in Dilute Aqueous and Nonaqueous Solution

“…Obviously, the hyperbranched macromolecules form very compact structures in both solvents. The slopes can be compared to the results by Gelade et al 11 and de Luca et al, 12 who found slopes of 0.6 and 0.4, respectively. In the latter cases organic solvents were studied.…”

“…Gelade et al 11 and de Luca et al 12 reported SANS experiments on fractionated hyperbranched poly-(ester amide)s and polyesters in organic solvents. They † GKSS Research Centre.…”

Computer simulations of hyperbranched polymers: The influence of the Wiener index on the intrinsic viscosity and radius of gyration

“…By use of the appropriate values, large numbers (5ϫ10 6 to 1ϫ10 7 ) of different structures were generated at target DBs of 0.4, 0.6, and 0. For each N and DB value, structures with W values corresponding to the maximum in the distribution and two additional structures on either side of the maximum at onefourth the intensity of the maximum were saved for simulation.…”

“…Within other efforts, a monotonic increase of ͓ ͔ with N more akin to the Mark-Houwink behavior of linear polymers was observed, regardless of the degree of branching. [7][8][9][10] The conflicting message of these measurements may in part be due to the difficulty associated with characterizing these materials using size exclusion chromatography ͑SEC͒. The noted polydispersities in N and DB complicate the interpretation of SEC applied to HPs since a highly branched molecule with a large value of N can have the same hydrodynamic volume as a less branched or linear molecule with a smaller value of N.…”

Development of DSM's hybrane® hyperbranched polyesteramides

“…Combined with the application of mathematical models, the results of the analytical work confirmed that the ideas of the chemists indeed gave full control over the structures as described above. We published the work in the form of two extensive articles, 11,12 which unexpectedly also yielded us the annual DSM Publication Award (Fig. 6).…”