The aim of this work was to study the feasibility of hyperbranched polymers as drug carriers by employing different microparticle formation methods and the influence of loading methods on release kinetics. Commercially available hyperbranched polyester (Perstorp) and three polyesteramides (DSM) were loaded with the pharmaceutical acetaminophen. The gas antisolvent precipitation (GAS), the coacervation, and the particles from gas saturated solutions (PGSS) are among conventional processes that were used to prepare microparticles of drug-loaded hyperbranched polyesters for the first time. For preparing solid dispersions of drug-loaded hyperbranched polyesteramides the solvent method was applied. Infrared (IR) and differential thermal analysis (DTA) studies suggest that acetaminophen is partly dissolved in the polymer matrix and partly crystallized outside the polymer matrix. For acetaminophen-loaded polyesters prepared by the GAS method, the presence of free drugs is predominant when compared to microparticles prepared by the coacervation method. This event disappears for microparticles prepared by the PGSS method. Moreover, the release of drug from drug-loaded Bol-GAS is biphasic, where the initial burst (48%), indicating the presence of unincorporated drugs, is followed by a slow-release phase, suggesting the diffusion of drug through polymer matrices. The release of drugs from drug-loaded Bol-PGSS do not show this behavior since the drug is better dissolved or dispersed in polymer matrices. In the case of drug-loaded polyesteramides, coevaporates prepared from 3 hyperbranched structures (H1690, H1200, and H1500) using the solvent method result in different release kinetics. The hydrophobic characteristic of hyperbranched polyesteramide H1500 shows the biphasic release kinetic whereas the drug released from hydrophilic matrices H1690 and H1200 exhibits fast release comparable to that of pure drug.

In this work, the potential of low-viscous branched polymers for gas separation applications such as CO 2 absorption from flue gas is examined. Carbon dioxide and nitrogen solubilities are measured at low pressures for linear and branched polyethers, hyperbranched polyesters, and polyamines such as a polyamidoamine and a polyethylene imine as well as in their aqueous solutions. The results are reported in terms of Henry constants in the temperature range T ) 310-370 K. The densities of the pure polymers and their aqueous solutions are measured between T ) 293.15 and 363.15 K. The selectivities of the polymers for CO 2 /N 2 and the enthalpies of absorption at infinite dilution are determined. The group-contribution method UNIFAC-FV is applied to the CO 2 solubilities in polyethers and the hyperbranched polyester. It has been shown that branched polymers are promising candidates for gas absorbents with a high capacity for CO 2 and with large selectivities. The UNIFAC-FV model is able to predict the CO 2 solubilities in the investigated polymers.

The understanding of the phase behavior of dendritic polymers, i.e., hyperbranched polymers and dendrimers, is still in its infancy. No systematic thermodynamic investigations on the phase behavior of dendritic polymer solutions have been reported so far. Therefore, this experimental study focuses on the low- and high-pressure phase behavior of hyperbranched polymer−solvent and hyperbranched polymer−solvent−supercritical gas systems. The influence of the solvent polarity, the nature and number of polymer functionalities, and the degree of polymer branching, as well as the polymer and supercritical gas concentration on the phase behavior of selected hyperbranched polymer solutions, is discussed. Thermodynamic phenomena such as the merging of the upper critical solution temperature (UCST) and the lower critical solution temperature (LCST) curves, the pH dependence of the polymer solubility and a remarkably distinct solutropic phase behavior are presented.

New amines for reactive absorption of CO 2 from process gases were investigated in a comprehensive experimental screening. All studied amines are derivates of triacetoneamine and differ only in the substituent of the triacetoneamine ring structure. The amines are abbreviated by the acronym EvA with a consecutive number, designating the derivate. About 50 EvAs were considered in this work from which 26 were actually synthesized and investigated in aqueous solution. The mass fraction of the amines in the unloaded solution was eitherw 0 EvA = 0.05 g/g orw 0 EvA = 0.4 g/g. The following properties were studied: solubility of CO 2 , rate of absorption of CO 2 , liquid-liquid and solid-liquid equilibrium, foaming behavior, dynamic viscosity, and acid constants. The nine most promising EvAs were evaluated with the NoVa short-cut method [1]. The method yields estimates for the specific energy demand and recirculation rate for a given purification task. Two typical purification tasks were considered: the CO 2 -removal from natural gas and from synthesis gas, respectively. Some of the EvAs showed significantly improved performance compared to monoethanolamine (MEA) and a solvent-blend of methyl-diethanolamine and piperazine (MDEA/PZ).

Different thermodynamic properties of aqueous solutions of butyltriacetonediamine (BuTAD), unloaded and loaded with carbon dioxide, are studied experimentally. For unloaded mixtures of BuTAD and water, protonation equilibrium constants between 283 and 333 K and liquid–liquid equilibria between 313 and 353 K, including the lower critical point, are determined at atmospheric pressure. Furthermore, the solubility of carbon dioxide in aqueous solutions of BuTAD between 313 and 393 K is determined at low loadings with an analytic method based on headspace gas chromatography and at high loadings with a synthetic method using a high pressure view cell. In the loaded system, solid precipitation, liquid–liquid phase split, and the presence of metastable states are observed in certain ranges. The data is interesting for assessing the aqueous solution of BuTAD as solvent for carbon capture. A short-cut method is used for comparing the new solvent with an aqueous solution of monoethanolamine (MEA) with respect to the energy requirement of an absorption/desorption process for CO2 scrubbing. Furthermore, a new and simple gas chromatographic method for determining the loading with carbon dioxide of aqueous solutions of amines is described.