| Abstract
| - We study the melt rheology and molecular weight distribution of four short chain branchedhyperbranched polyesters with different molecular weights and containing branched monomers of variousalkyl chain lengths n (2 → 4; n is the number of CH2 groups in the alkyl chain). We find that the molecularweight distribution for all our samples obeys the static scaling form n(M) ∼ M-τexp(−M/Mchar) wheren(M) is the number density of hyperbranched polymers with mass M, Mchar is the largest characteristicmolecular weight, and τ is the polydispersity exponent. The values of τ for all our samples (either 1.35 or1.55) are close to but not the same as the mean field value of τ = 1.5, a consequence of the fact that ourpolymers were synthesized under non-mean-field polycondensation conditions. For all our samples, wefound that the rheology at low and intermediate frequencies could be modeled accurately using a dynamicscaling theory based on the Rouse model. This confirms that these hyperbranched polymers behave aspolymeric fractals which are essentially unentangled. For these polymers, the fractal dimension in themelt was found to be consistent with the hyperscaling relation for hyperbranched polymers df = 3, althoughwe found rheology to be rather insensitive to df for our system.
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