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stirred for 1 h, the mixture was filtered and the filtrate cooled to 0 °C and acidified with 35 mL of concentrated HC1. Evaporation of the water in vacuo, followed by thorough drying of the residue at 100 °C in vacuo, yielded 40.3 g (73%) of HOPC1, mp 160-164 °C, NMR (D20) 4.83 (s, 3 ), 8.50 (m, 2 H), 8.92 (m, 2 H), which gave a satisfactory equivalent weight on titration with AgN03.Solution Preparation. The mixed solvents were prepared from weighed amounts of distilled water and ethanol or dimethyl sulfoxide. Dissolved carbon dioxide was removed from all solvents by passing C02-free nitrogen gas through a sintered glass bubbler immersed in the solvent. HOAI and HOPC1 solutions were prepared by weight, followed by dilution when necessary. NaOH solutions were standardized by titration with HC1.Heats of Reaction. The heats of reaction were measured at 25.0 °C with an LKB 8700-2 titration calorimeter. Solutions of HOPC1 or HOAI, 1-10 mL, at concentrations ranging from 0.005 to 0.05 M were added to 90 mL of NaOH solution having the same concentration as the phenol. In some cases, the procedure was reversed and the NaOH solution was titrated into an excess of phenol solution. Both procedures gave the same results. Heat of dilution corrections were found to be insignificant. In the aqueous cases, allowance was also made for the partial ionization of the phenol by using the ionization equilibrium constant of the phenol and the heat of dissociation of H20. This correction was found to be less than 1 % in all cases.Heats of Solution. Heats of solution were measured with an LKB 8700-1 reaction and solution calorimeter.

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.

Polycondensation of 1,2-cyclohexane dicarboxylic anhydride with a calculated molar excess of di-2-propanolamine led to bis(2-hydroxyalkyl)amide based hydroxy-functional hyperbranched polyesteramides in a straightforward manner. Modification reactions of these polymers with lauric esters was conducted in different synthetic approaches. The obtained polymers were characterized by mass spectrometry, using electrospray ionization (ESI) and matrix assisted laser desorption ionization/timeof-flight (MALDI-TOF) techniques, and by size exclusion chromatography in combination with on-line viscosimetry detection (SEC-DV). Comparison of the experimental results with theoretical calculations showed a satisfactory match on molecular weights and polydispersities with fully modified polyesteramides. These values were found to deviate with unmodified and, to a smaller extent, with partially modified polyesteramides. This phenomenon could be attributed to side reactions of the 2-hydroxypropylamide end groups. The lauric ester modified polyesteramides obtained from either consecutive or simultaneous polycondensation and lauric acid esterification were found to be quite similar in structure and molecular weight distribution. This observation underlined the influence of transesterification reactions under the applied conditions.

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