Blocked isocyanate functional oligomers and liquid rubbers are prepared by a novel, solventfree carbonylbiscaprolactam (CBC) mediated end group conversion reaction of amine-terminated oligodimethylsiloxanes (PDMS) and oligopropyleneoxides (PPO), with molar masses varying between 400 and 3140 g/mol, and of hydroxy-terminated oligoethylene oxide (PEG), oligopropyleneoxide (PPO) and oligotetrahydrofuran (PTHF), with molar masses of around 1000 g/mol. The key reaction is the carbonylbiscaprolactam (CBC) mediated amino or hydroxy end group conversion yielding carbamoyl caprolactam functional polymers, without requiring addition of either phosgene or isocyanates. The quantitative CBC conversion of amine end groups occurred in bulk at 100°C in the absence of catalysts, yielding N-carbamoyl caprolactam terminated oligomers and caprolactam (ring elimination, pathway RE). The reaction of hydroxy end groups at 100 to 150°C in the presence of catalysts such as zirconium alcoholates, magnesium bromide or dibutyltindilaurate (DBTDL) produced N-carbamoyl caprolactam end groups via nucleophilic attack of the hydroxy group at one of the CBC caprolactam rings and subsequent ring opening (ring opening, pathway RO). The CBC reactions were monitored by means of ReactIR, 1 H NMR and 13 C NMR spectroscopy. The molecular masses of the oligomers and liquid rubbers with caprolactam-blocked isocyanate end groups were measured by means of MALDI-ToF mass spectroscopy and size exclusion chromatography (SEC). The thermal behavior and deblocking temperatures of the caprolactam-blocked isocyanates obtained were examined by means of thermogravimetric analysis (TGA).

The power of the rings: The reactions of carbonylbiscaprolactam (CBC, 1) with amines and alcohols proceed either by ring elimination (RE) or by ring opening (RO). The conversion and selectivity of these reactions were optimized in studies with various hydroxy and amino compounds, catalysts, reaction temperatures, and ratios of 1/nucleophile.

The polymerization of N,N' carbonylbis (caprolactam) (CBC) and polyol in the presence of alcoholate as catalyst produced cross-linked poly(ester-urea)s via ring opening addition reaction. In contrast to conventional synthetic routes, the use of non-toxic CBC eliminates the need for toxic isocyanate-based monomers. The structure of the molecules resulting from model reactions was confirmed using FT-IR and (1)H- and (13)C-NMR spectroscopy. Poly(ester-urea) networks exhibit rubber-like mechanical properties and high-temperature stability. Cell adhesion and cell growth on the polymers evidenced the high biocompatibility of the material. Degradation of the poly(ester-urea)s was investigated at 70 degrees C in neutral and basic aqueous solution. The degradation depends on the swelling behavior of the samples. Mechanical properties, good biocompatibility, and degradation behavior of the CBC/polyol-based polymers make them interesting materials for biomedical applications.

The use of hot-melt extrusion for preparing homogeneous API-excipient mixtures is studied for miconazole-PEG-g-PVA [poly(ethylene glycol)-poly(vinyl alcohol) graft copolymer] solid dispersions with a 5 cm(3) table-top, twin-screw corotating microcompounder (DSM Xplore). Phase behavior of PEG-g-PVA, miscibility of miconazole in PEG-g-PVA and the partitioning of miconazole between PEG and PVA amorphous phases are characterized using a combination of modulated DSC, XRPD, and solid-state (1)H and (13)C NMR methods. The (1)H NMR transverse magnetization relaxation (T(2) relaxation) method is used to analyze the phase composition and molecular mobility of the copolymer. The T(2) relaxation decay of pure PEG-g-PVA can be described by four T(2) relaxation components in the temperature range studied. PVA crystallinity is not largely affected by hot-melt extrusion and the presence of the drug. Miconazole preferably resides in the PEG amorphous phase, and its molecules are well dispersed in the PEG-g-PVA matrix using hot-melt extrusion mixing. Miconazole forms amorphous nanoclusters whose average size equals approximately 1.6 nm, indicating solid solution formation (molecular level dispersion) of the drug in the polymer.