Dirk Muscat

Hyperbranched Polyesteramides — New Dendritic Polymers

Hyperbranched polyesteramides based on commercially attractive monomers have been successfully developed, affording polymers with a high number of end groups and especially multifunctionality on the same molecule. Beside hydroxyl and carboxylic acid groups, hyperbranched polyesteramides can be modified with a broad variety of other functionalities such as unsaturated groups, tertiary amines, or long alkyl chains. Thus the concept of the synthesis allows a broad variety of structures and the resulting properties like polarity or viscosity can be adjusted and fine-tuned for a broad number of applications. This enables the hyperbranched polyesteramides to be used in a variety of (potential) applications, such as crosslinkers in coatings, as toner resin, for dyeing polyolefins, as surfactants, or in cosmetics. Especially impressive is the disperse dyeing of polypropylene fibers, which has been a problem for decades. Hyperbranched polyesteramides based on phthalic anhydride and diisopropanolamine, partially functionalized with stearic acid represent amphiphilic molecules, which are able to fix the dyes via their polar core and at the same time are compatible with the polypropylene matrix through their long alkyl chains.

In-source decay of hyperbranched polyesteramides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Hyperbranched polyesteramides (DA2), prepared from hexahydrophthalic anhydride (D) and diisopropanolamine (A) have been characterized, by use of matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF-MS), field desorption (FD)-MS, and electrospray ionization (ESI)-MS. MALDI of polyesteramides produces protonated molecules. The spectra show a complex chemical composition distribution and end-group distribution which are mainly composed of two series of homologous oligomers DnAn+1 − mzH2O and DnAn − mH2O, where m = 1–2. Signals from protonated molecules DnAn+1 and DnAn are almost absent in the MALDI spectrum, whereas these ions are responsible for the base peak of DnAn+1 − mH2O and DnAn − mH2O (m = 1–2) clusters in the ESI spectrum. The absence of −OH end-groups signals in the MALDI spectrum is due to a metastable decay of protonated DnAn+1 and DnAn ions in the ion source of the MALDI mass spectrometer prior to ion extraction. In-source decay results in the formation of protonated lower DnAn+1 − mH2O and DnAn − mH2O oligomers and their corresponding neutrals, leading to wrong conclusions concerning the relative end-group distribution as a function of the degree of polymerization and the chemical composition.