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

Comparison of phase structures and surface free energy values for the coatings synthesised from linear polyurethanes and from waterborne polyurethane cationomers

WAXS, DSC and AFM methods were employed to compare phase structures of the coatings obtained from waterborne polyurethane cationomers which had been synthesised in the reaction of some diisocyanates (MDI, IPDI, TDI and HDI) with polyoxyethylene glycols (M = 600 and 2,000) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. The structures were also analysed of the coatings derived from linear polyurethanes which had been synthesised on the basis of similar raw materials. Better rigidity was found for generally amorphous cationomer coats. Changes were discussed in the surface free energy (SFE) values and in their components, as calculated independently with the use of the van Oss–Good and Owens–Wendt methods. Polyurethane coats turned out more hydrophobic as compared to cationomer ones. In both coat types, fluorine incorporated into cationomers contributed to lower SFE values: from 50 down to about 30 mJ/m2

Comparison of the Porous Structure of Polymeric Beads Obtained by Modified Suspension and Multi-Step Swelling Polymerizations

The porous structures of the polymeric beads obtained by modified suspension and multi-step swelling polymerizations were studied. A porous styrene–divinylbenzene copolymer (ST–DVB) was synthesized in the modified suspension polymerization. In the multi-step polymerization, porous ST–DVB layers of the same chemical composition as obtained in the suspension polymerization were embedded onto polystyrene seed particles obtained in the first step. Three methods were used for investigating the porous structures generated. These were inverse exclusion chromatography, nitrogen adsorption and small X-ray scattering (SAXS). The former was used to characterize the polymer in the swollen state, whereas the latter two were employed with dry polymer samples. The results obtained showed that polystyrene seed particles are porous in the swollen state. However, such pores could not be detected either by nitrogen adsorption or SAXS methods

Synthesis of new mesostructured cellular foams (MCFs) with NaY zeolite and their application to sorption of thorium ions

The paper presents the new way of preparation of MCF foams with NaY zeolite. Significant changes in the amount of micro and mesopores in relation to the amount of NaY zeolite and 1,3,5-trimethylbenzene (TMB) added during the synthesis was observed. It suggests the possibility of controlling the micro/mesopores ratio by applying the proposed method. Environmental aspects of using new MCF/NaY foams is related to the adsorption of thorium ions (Th+4). The term of “MCF/NaY materials” refers to the general name of the material without referring to the content and state of zeolite. The obtained materials were highly effective in relation to Th+4. The adsorption capacity was greater when the number of micropores was lower. The dependence of adsorption capacity of Th+4 ions on aluminum atoms content was also confirmed

Synthesis of citrates of selected lanthanides (Er, Ho and Lu)

Holmium, erbium and lutetium citrates can be synthesized by transforming freshly precipitated holmium, erbium and lutetium hydroxides in the citric acid solution under the hydrothermal conditions (above 100 ℃) after 3 days of reaction. In this paper in order to determine the synthesis conditions, the hydroxide and citrate stability areas of selected lanthanides were compared. The studies of the structure of the obtained holmium citrate, erbium and lutetium samples showed that these compounds crystallize in a monoclinic system. The crystallite sizes determined by the HalderWagner method were 67.8 ± 8.0nm, 103.7 ± 4.5nm and 68.1 ± 4.2nm, respectively for the holmium citrate, erbium citrate and lutetium citrate samples. The shifts of the hydroxyl and carboxyl groups of citric acid in the FTIR spectrum indicate the interactions of both groups with holmium, erbium and lutetium cations. Then the obtained samples were subjected to the analysis of composition, and their particle size distribution was determined

Application of the de Job method in the evaluation of the stoichiometry of uranyl phosphate complexes sorbed on bentonite

For the first time, the continuous variation method was applied for the evaluation of the stoichiometry of uranyl phosphate complexes sorbed on bentonite. Sorption of UO2(CH3COO)2⋅2H2O in the presence of Na2HPO4⋅7H2O from 0.001 mol/L solutions led to the appearance of maxima in the sorption peaks of U(VI) and P(V) ions at molar ratios of [U(VI)]/[P(V)]s = 1.4, 3.3, 3.6 and 1.2, 1.7. It is suggested, based on complementary XRD and XPS data, that the UO2HPO4 complex is located on aluminols (ºAl-OH) whereas the (UO2)3(PO4)2⋅4H2O complex is precipitated in the interlamellar space of bentonite. The participation of (UO2)3(OH)5+ and (UO2)4(OH)7+ species in the formation of U(VI) surface complexes is suggested, based on the deconvolution of sorption spectra of U(VI) on the bentonite in the presence of phosphates