Session: POLY/PMSE Poster Session:

The physical properties of hyperbranched polymers (HBPs) based on 2,2-bis(hydroxymethyl) propionic acid (bis-MPA), have been widely studied, and are largely influenced by the presence of hydrogen bonds (H-bonds). However, similar studies and characterization have not yet been extended to bis-MPA based dendrimers which require considerable synthetic effort. Herein, hydrogen bond organization and interrelated structural order formation of a bis-MPA based dendrimers of the first through third generation (D1-3) were investigated as compared to their commercially available counterpart Boltorn H20, which is widely used in the coatings industry. Initial dielectric investigations show that both Boltorn H20 and D2 have high dielectric constants as compared to their linear analogs due to these H-bonded clusters. Molecular dynamics (MD) simulations were used to predict the WAXS spectra and reveal ‘chain-like’ clusters of H-bonds. The length distribution of these clusters over the three generations were compared and contributions of different proton acceptors were analyzed. Computational results agree well with experimental data previously obtained and show that D2 has the highest propensity of forming long H-bonded clusters. This indicates that not only are dendrimers more capable of forming long cluster associations but also that the second-generation dendrimer is a “sweet spot” for terminal hydroxyls to cluster length associations.

Left is an example of a simulated D2 unit cell<br /> Right: resulting XRD data from simulated unit cells compared with experimental data

Left is an example of a simulated D2 unit cell
Right: resulting XRD data from simulated unit cells compared with experimental data

Brian Olson

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