Paweł Parzuchowski

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.

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.

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.

Fluoride-selective polymeric membrane electrodes based on Zr(IV)- and Al(III)-salen ionophores of various structures.

Al(III)- and Zr(IV)-salophens of novel structures were tested as anion-selective ionophores. It was shown that these compounds are highly selective to fluoride and give selectivity greatly deviating from classical Hofmeister pattern, when doped into the polymeric membrane of ion-selective electrode (ISE). The following selectivity sequence has been recorded for both ionophores: F(-) > ClO(4)(-) > SCN(-) > NO(3)(-) approximately Br(-) approximately Cl(-). The results of potentiometric and spectrophotometric measurements allow to conclude that the nature and structure of salophen ligands influence stability of ISE working parameters. An increase in salophen ligands lipophilicity results in prolongation of the ISE lifetime, most likely due to slower ionophore decomposition caused by the hydrolysis of imine bonds in salophen structure. Ion-selective electrodes (ISEs) with the most successful Al(III)-salophen exhibited a stable, fast and near-Nernstian fluoride response and a functional lifetime near 3 weeks and selectivity coefficients with log K(F(-), Y(-))(pot) as follows: -2.8 (Y(-)=Br(-)), -2.7 (Cl(-)), -2.8 (NO(3)(-)), -1.5 (SCN(-)), -1.3 (ClO(4)(-)), which is better than for other ones based on Zr(IV)- and Al(III)-salophens and salens described to date.

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.

Novel Optical Material: Polyarylates with Heterocyclic Side Chain Groups

ABSTRACT: Several nonlinear optical polymers containing azometine side-chain groupshave been obtained by interfacial polycondensation. The structures of obtained mono-mers and polymers were confirmed by infrared, 1 H-NMR, and ultraviolet spectrosco-pies. Mechanical, thermal, and optical properties of the obtained polymers were eval-uated. The investigations show that some of the new polymers obtained in this studymay find use in optical applications.

Improved Water Resistance and Adhesive Performance of a Commercial UF Resin Blended with Glutaraldehyde

The influence of glutaraldehyde blend on the properties of a commercially available resin in moist conditions was investigated. A UF resin with very low water resistance was blended with glutaraldehyde prior to the thermosetting step and the adhesive performance of the modified adhesive systems was studied. Experiments were performed on birch two-layer co-oriented plywood. It was shown that blending a commercial glue-mix as sold with glutaraldehyde can be an effective way to improve water resistance of the glue without introducing additional –NH2 moiety. It was also found that glutaraldehyde does not deteriorate properties of the glue in the dry state, while glue susceptibility to boiling water is markedly reduced.

Hyperbranched Polyether as a Modifying Agent for Urea-Formaldehyde Resins—Hardness and Strength Control Tool

A commercially available urea-formaldehyde (UF) resin was blended with a hyperbranched polyether (HBP) obtained from glycerol being a by-product in biodiesel production. The mechanical properties of the cured polymeric blends are described in this article. It was found that low addition (3 wt%) of the modifier significantly improves the hardness (16%) and the compressive shear strength (17%) of the polymer, whereas water absorption remains unaffected. It was also shown that blending UF resins with hyperbranched polyethers can be an effective tool for controlling mechanical properties and dimensional stability of the polymeric systems.

Synthesis, characterization and reactivity of a six-membered cyclic glycerol carbonate bearing a free hydroxyl group

Five- and six-membered cyclic carbonates have recently become popular as starting materials for the synthesis of polycarbonates via ring opening polymerization or synthesis of environmentally friendly non-isocyanate polyurethanes. In many cases a five-membered glycerol carbonate has been used in these applications. However, the simplest derivative of glycerol, a six-membered cyclic glycerol carbonate (5-hydroxy-1,3-dioxan-2-one), has not been reported so far. In this work, for the first time, we report a procedure for the synthesis of this monomer from glycerol. The product was characterized by 1H NMR, 13C NMR, and FTIR spectroscopy and X-ray diffraction measurements. Further, the synthesis of bis(2-oxo-1,3-dioxan-5-yl) sebacate, a biscyclic six-membered carbonate, was described. The reactivities of 5-hydroxy-1,3-dioxan-2-one and its biscyclic ester derivative were investigated. No ring opening polymerization of both the monomers was observed, instead an isomerization to appropriate five-membered cyclic carbonates occurred. Unfortunately, the protection of the hydroxyl group 2 with an ester type substituent does not protect it against isomerisation.

Informational rigidity in mesitylene-based calix[4]arenes adopting a 1,3-alternate conformation

Abstract Two chiral derivatives of a mesitylene-based calix[4]arene known to exist in the 1,3-alternate conformation were prepared by the attachment of homochiral residues to the four exo -hydroxy groups. Thus, the enantiotopic protons of the central scaffold became diastereotopic, leading to a doubling of their 1 H NMR signals in one example. From the temperature independence of the NMR spectrum, a lower limit of 24.2 kcal/mol could be estimated for the barrier of ring inversion. MM3 calculations confirm the 1,3-alternate conformation as the energy minimum, and estimate a barrier of 25.7 kcal/mol for the 1,3-alternate-to-1,3-alternate* interconversion process. This high barrier is due to the repulsive steric interactions between exo -methyl groups at vicinal rings when these groups pass each other.