Synthesis of PMMA-b-PU-b-PMMA tri-block copolymers through ARGET ATRP in the presence of air

ARGET (activators regenerated by electron transfer) ATRP (atom transfer radical polymerization) has been successfully performed (in flasks fitted with rubber septa without the need for use of Schlenk line) in the presence of limited amount of air and with a very small (370 ppm) amount of copper catalyst together with an appropriate reducing agent Cu(0). Novelty of this work is that the poly(methyl methacrylate)-block-polyurethane-block-poly(methyl methacrylate) triblock copolymers were synthesized for the first time through ARGET ATRP, by using tertiary bromine-terminated polyurethane as a macroinitiator (MBP-PU-MBP), CuBr2 or CuCl2 as a catalyst and N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) or 2,2'-bipyridine (Bpy) as a complexing agent. As the polymerization time increases, both the monomer conversion and ln([M]0/[M]) increased and the molecular weight of copolymer increases linearly with increasing conversion. Theoretical number-average molecular weight (Mn, th) of the tri-block copolymers was found to be comparable with number-average molecular weight determined by GPC analyses (Mn, GPC). These results indicate that the formation of the tri-block copolymers was through atom transfer radical polymerization mechanism. 1H and 13C NMR spectral methods were employed to confirm chemical structures of synthesized macroinitiator and tri-block copolymers. Mole percentage of PMMA in the tri-block copolymers was calculated using 1H NMR spectroscopy and was found to be comparable with the GPC results. Additionally, the studies of surface properties (confocal microscopy and SFE) of tri-block copolymer coatings confirmed the presence of MMA segments

Multidisciplinary approach to a patient with end-stage heart failure and colon adenocarcinoma — intra aortic balloon pump-supported tumor resection and bridge to heart transplantation

Non-cardiac, potentially curative surgeries in patients with chronic end-stage heart failure and significant arrhythmias are associated with very high risk of adverse events and mortality. A hemodynamic support in this clinical scenario is a novel and reasonable approach. Intra-aortic balloon pump (IABP), with its feasibility, long-term safety record, minimal invasiveness and availability, constitutes the best and valid option. As an example we present a case of an IABP supported colon adenocarcinoma resection in a patient with end stage heart failure.Niekardiologiczne, naprawcze zabiegi operacyjne u chorych w schyłkowej fazie niewydolności serca oraz z istotnymi zaburzeń rytmu serca są obarczone bardzo wysokim ryzykiem wystąpienia niepożądanych zdarzeń lub zgonu. W tej sytuacji wsparcie hemodynamiczne może być nowatorskim i uzasadnionym wyborem. Kontrapulsacja wewnątrzaortalna, metoda szeroko dostępna, mało inwazyjna i bezpieczna wydaje się być najbardziej interesującą opcją. Wobec powyższego prezentujemy przypadek implantacji kontrapulsacji wewnątrzaortalnej przed operacją resekcji gruczolakoraka okrężnicy u chorego w schyłkowej fazie niewydolnością serca

Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. 1H, 13C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on 1H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss–Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m2. That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions

Cellulose-based graft copolymers prepared by simplified electrochemically mediated ATRP

Brush-shaped block copolymer with a dual hydrophilic poly(acrylic acid)-block-poly(oligo(ethylene glycol) acrylate) (PAA-b-POEGA) arms was synthesized for the first time via a simplified electrochemically mediated ATRP (seATRP) under both constant potential electrolysis and constant current electrolysis conditions, utilizing only 30 ppm of catalyst complex. The polymerization conditions were optimized to provide fast reactions while employing low catalyst concentrations and preparation of cellulose-based brush-like copolymers with narrow molecular weight distributions. The results from proton nuclear magnetic resonance (1H NMR) spectral studies support the formation of cellulose-based graft (co)polymers. It is expected that these new polymer brushes may find application as pH- and thermo-sensitive drug delivery systems