Gabriel Rokicki

Hyperbranched aliphatic polyethers obtained from environmentally benign monomer: glycerol carbonate

A hyperbranched aliphatic polyether with hydroxyl end groups was produced from glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one)—the benign monomer obtained from renewable starting materials: glycerol and dimethyl carbonate. Anionic polymerization of glycerol carbonate, which proceeds with simultaneous decarboxylation, was performed using partially deprotonated trimethylolpropane (TMP) as an initiator. Pendant hydroxyl groups facilitate the ring-opening multibranching polymerization leading to a hyperbranched polyether. 13C NMR analysis of the polymerization products confirmed the presence of linear, dendritic, and terminal repeating units. MALDI-TOF mass spectrum analysis confirmed the presence of TMP and glycerol core containing branched structures as well as a relatively small amount of macromolecules with cyclic groups. The polymers were soluble in water, THF, methanol and DMSO.

A new route to polyurethanes from ethylene carbonate, diamines and diols

Abstract A new method of the synthesis of aliphatic polyurethanes from diamines and diols or alternatively from α,ω-aminoalcohols using ethylene carbonate as a substitute of phosgene is presented. It has been found that the transurethanisation reaction between α,ω-bis(2-hydroxyethoxycarbonylamino)alkanes and diols containing six or more carbon atoms in a molecule carried out in the presence of tin coordination catalysts, leads to [n,m]polyurethane, and ethylene glycol formed as a side-product. In the case of using aminoalcohols, the reaction with ethylene carbonate leads to [n]polyurethanes. The polymerisation products were analysed by means of 1H and 13C NMR spectroscopy, as well as MALDI-TOF mass spectrometry. The influence of the reaction conditions on the chemical structure of the reaction products and a plausible reaction mechanism are discussed.

Novel approach of immobilization of calix[4]arene type ionophore in 'self-plasticized' polymeric membrane

Abstract The design of ion-selective membranes based on the immobilization of the calix[4]arene tetraethyl ester containing at their wider rim one polymerizable group in a linear isodecyl acrylate (IDA)/methyl methacrylate (MM) copolymer is reported. Preliminary studies were focused on an optimization of polymeric matrix based on IDA/MM copolymers to make them suitable for preparing ion-selective membranes. The effect of polymer composition (IDA:MM ratio), matrix features (glass transition temperature and molecular weight) and compatibility with electro-active components was examined. It was found that the copolymer of IDA:MM=3:7 ratio exhibited the best mechanical properties. The feasibility of the application of IDA/MM matrix for ion-selective membranes was examined using as a model ionophore, 4- tert -butyl calix[4]arene tetraethyl ester. Electrodes based on these membranes showed near theoretical sensitivity towards sodium concentration and selectivity similar to reported for classical plasticized PVC-based membranes. Methacrylamide derivative of calixarene was immobilized in IDA/MM polymer of optimized composition. Potentiometric measurements revealed that the selectivity and the slope of the response curve obtained for electrodes employing membranes with immobilized calixarene are essentially the same as for the membranes containing a free ionophore, while the lifetime was improved from 2 to 6 months.

Synthesis of oligocarbonate diols and their characterization by MALDI-TOF spectrometry

A method of the synthesis of oligocarbonate diols from five-membered cyclic carbonates and aliphatic diols using azeotropic solvents is presented. The influence of a catalyst and reaction conditions on the alkylene oxide and alkylene carbonate insertion into macrodiol molecules were studied and the reaction mechanism is discussed. The oligomeric products were analyzed by means of MALDI-TOF mass spectrometry. The transesterification reaction between propylene carbonate and diols containing six or more carbon atoms in a molecule carried out in the presence of the coordination catalysts such as tin or zinc carboxylate leads to almost pure oligocarbonate diols.

Intramolecular etherification of five-membered cyclic carbonates bearing hydroxyalkyl groups

We report a new one-pot synthetic route to tetrahydrofuran derivatives, which were unexpectedly produced under basic conditions by intramolecular etherification of substituted five-membered cyclic carbonates. For alcohols with vicinal hydroxyl groups, and additional OH groups at the β-position, intramolecular etherification leading to 3-hydroxytetrahydrofuran derivatives was observed. These reactions were studied for compounds having from 2 to 6 hydroxyl groups per molecule, and the mechanism was proposed. The developed method provides a new environmentally friendly approach to the synthesis of five-membered cyclic ether derivatives under non-acidic conditions.

Calix[4]arene derived tetraester receptors modified at their wide rim by polymerizable groups

The synthesis of calix[4]arene tetraester ionophores containing polymerizable groups at their wider rim is reported. Calixarene monomers with one or two methacrylamide groups were copolymerized with methyl methacrylate, yielding linear polymers with pendant calixarene groups or crosslinked polymers. Extraction studies with the soluble copolymers and with the corresponding pivalamides as model compounds showed no difference in the extraction ability and selectivity. Potentiometric measurements of membrane electrodes prepared with the polymeric calixarene ionophores indicated that the high selectivity, the slope of the response curve and the low detection limit of membranes containing non-bonded calixarene ionophores are retained while the lifetime of the polymeric membranes is increased.

Waterborne unsaturated polyester resins

The transformation of solvent soluble unsaturated polyester resins into resins able to form stable water dispersion is presented in this paper. The methods of modification are discussed, consisting of the introduction of polar hydrophilic groups such as carboxylic and sulfonic ones (sodium 5-sulfonatoisophthalic acid) into the resin molecule, which ensure good tolerance with water. Instead of styrene, glycerol monoethers of allyl alcohol and unsaturated fatty alcohols were used as reactive built-in crosslinking monomers for resin modification. The influence of the resin composition and method of synthesis on the dispersion stability and properties of photocurable lacquer coatings obtained from the waterborne resins were investigated.

EFFECT OF GLASS TRANSITION TEMPERATURE OF POLYMERIC BINDERS ON PROPERTIES CERAMIC MATERIALS

In the paper are presented the studies of the effect of glass transition temperature of new water-thinnable polymeric binders on the properties of ceramic materials obtained by die pressing. The parameters of ceramic samples comprising polymeric binders have been compared with those of samples comprising poly(vinyl alcohol) (PVA) — water-soluble binder. When using poly(acrylic-styrene) (AS), poly(acrylic-allyl) (AA) and poly(vinyl-allyl) (VA) water-thinnable binders, materials of greater density and mechanical strength were obtained in the green state as well as after sintering than those in the case of using PVA. The dependence of the chemical structure of the binders applied on the properties of samples such as the glass transition temperature and hydrophobic-hydrophilic balance of the copolymers has been discussed.

Crown ethers derived from bicyclocalix[4]arenes as chromoionophores

The synthesis of calix[4]arenes in which opposite phenolic units are connected by a poly(oxyethylene) bridge at the narrow rim and a 2,6-dimethylene-4-nitrophenol bridge at the wide rim is reported. For two derivatives with tetra- (4) and penta(oxyethylene) (5) bridges UV-Vis spectrophotometric studies were carried out in buffered solution in the presence of alkali metal ions. Their complexation was associated with changes in their UV-Vis spectra, especially with an increase of the absorption band at 450 nm. For 4 and 5 this was most intense in the presence of potassium and caesium ions, respectively, indicating that the calixarene with the shorter crown ether bridge is selective towards potassium ions and that with the longer bridge towards caesium ions. The X-ray structure analysis of 5 shows a pinched cone conformation for the 1,3-calixcrown part. The p-nitrophenol unit is parallel to one of the unbridged tert-butyl phenol units. Its hydroxyl group points into the cavity, in agreement with comparatively high pKa values. Molecular mechanics was used to model the geometry of the potassium and caesium complexes.

Water-Based Air-Drying Alkyd Polyester Resins Modified With Glycerol Allyl Ether

Abstract A water thinnable polyester alkyd resin containing glycerol allyl ether (GAE) was synthesized. The influence of the content of GAE for various degrees of molecule branching, expressed by the functionality of hydroxylic components, on the properties of the resin and coatings obtained from it was studied. It was found that the lacquers obtained from the alkyd resin containing 10–16 wt% GAE exhibit short drying time, good hardness of coatings, and good water resistance.