Polish Journal of Chemical Technology (v.11, #3)
Butyl acrylate/4-acryloyloxy benzophenone copolymers as photoreactive UV-crosslinkable pressure-sensitive adhesives
by Zbigniew Czech; Agnieszka Butwin; (pp. 1-4).
It has previously been shown that copolymers of butyl acrylate with 4-acryloyloxy benzophenone can be used as pressure-sensitive adhesives (PSAs). This paper presents the synthesis and application of a solvent-borne polymer system for the preparation of photoreactive UV-crosslinkable acrylic pressure-sensitive adhesives. Butyl acrylate/benzophenone copolymers with molecular mass in the range 180 000 to 480 000 Dalton were prepared by carrying out free-radical solution polymerization. These copolymers were found to be tacky but in some cases to possess insufficient cohesive strength after UV-crosslinking to be useful as PSAs. The other copolymers resulted in materials with the balance of cohesive and adhesive characteristics required of good PSAs. Some of the parameters affecting the pressure-sensitive adhesive properties of the copolymers are the concentration of 4-acryloyloxy benzophenone, the molecular mass of the polymeric components, the UV-reactivity, and properties such as tack, peel adhesion, and cohesion.
Keywords: butyl acrylate; 4-acryloyloxy benzophenone; acrylic copolymers; pressure-sensitive adhesives (PSAs); UV-crosslinking; tack; peel adhesion; cohesion
Novel catalytic synthesis of 6,7-dimethoxyisatin with the use of heteropolyacids (HPAs) as acid solid catalyst
by Ali Gharib; Mohsen Daneshtalab; J. (Hans) W. Scheeren; Fatemeh F. Bamoharram; Mina Roshani; Manouchehr Jahangir; (pp. 5-7).
An efficient method for the preparation of 6,7-dimethoxyisatin and its derivatives was developed with good yield by using Preyssler-type heteropolyacid (HPA) as acid catalyst under green conditions. The comparison between Keggin type heteropolyacids, H3[PW12O40], H4[SiW12O40] and H4[SiMo12O40], H3[PMo12O40] and mineral acids with Preyssler's anion shows that the latter possess better catalytical activity than the other heteropolyacids and no degradation of the structure was observed.
Keywords: Heteropolyacid; catalyst; Preyssler; Isatin; mandelonitrile
Effects of processing parameters on hydrolysis of TiOSO4
by Barbara Grzmil; Daniel Grela; Bogumił Kic; (pp. 15-21).
The influence of both TiOSO4 concentrations in the starting solution and a way of conducting hydrolysis on the degree of titanyl sulphate conversion to hydrated titanium dioxide were studied. Titanyl sulphate solution, an intermediate product in the commercial preparation of titanium dioxide pigments by sulphate method, was used. The continuous method of conducting hydrolysis was applied using one or two reactors connected in series. It was found that the degree of hydrolysis markedly depends on the studied parameters. It was also found that TiOSO4 hydrolysis using the continuous method should be conducted: i) at a possibly low concentration of free sulfuric acid in the solution and; ii) in two or more rectors connected in series.
Keywords: hydrate titanium dioxide; hydrolysis; titanyl sulfate; continuous method
Catalytic performances of cross-linking humic acids supported Pd/Ni bimetallic catalyst for heck reaction
by Qijie Xu; Lei Zhang; Wenzhong Shi; Yuanchen Cui; (pp. 22-26).
The cross-linking humic acids (CL-HAs), epichlorohydrin as the cross-linking reagent and the supported Pd/Ni bimetallic catalysts (CL-HAs-Pd/Ni) were prepared and characterized by IR, AAS, XPS, TEM. The effects of reaction time, temperature, base, solvent and the amount of catalyst on the properties of the catalyst were studied. These catalysts could catalyze the Heck reaction of aryl halides and substituted aryl halides with acrylic acids or styrene successfully; the yields were all above 95%.
Keywords: cross-linking humic acid; epichlorohydrin; Pd/Ni bimetallic catalyst; supported catalyst; Heck reaction
Morphology and mechanical properties of polyamide 12 (PA12)/poly(vinylidene fluoride) (PVDF) blends
by Aleksandra M. Ratajska; Wojciech P. Kulak; Artur Poeppel; Andreas Seyler; Zbigniew Roslaniec; (pp. 27-34).
The morphology, thermal and mechanical properties of polyamide 12 (PA12)/poly(vinylidene fluoride) (PVDF) blends were investigated. These polymers are engineering, semi-crystalline polymers which are reciprocally immiscible. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM) were used to characterize the polymeric materials. Mechanical properties were examined by static tensile test. The investigations demonstrate that blends with higher amount of PVDF, with the morphology of two co-continuous semicristalline phases, exhibit better mechanical properties. The blends with small content of PVDF and prepared by extrusion show the morphology of small separated domains of PVDF and full continuous PA phase. The morphology of these blends is different than the blends prepared by internal mixer and have better mechanical properties too. Thus they can be used in particular applications without a compatibilizing agent.
Keywords: blends; miscibility; polyamide 12 (PA12); poly(vinylidene fluoride) (PVDF); DSC; DMTA; SEM; mechanical properties
Crystal structure and spectroscopic properties of 4-acetaminopyridine and its protonated form
by Bojidarka B. Koleva; Rositsa Nikolova; Atanas Tchapkanov; Tsonko Kolev; Heike Mayer-Figge; Michael Spiteller; William S. Sheldrick; (pp. 35-40).
4-Acetaminopyridine dihydrate and its protonated form, stabilized as the hydrochloride salt have been synthesized and spectroscopic elucidated in solution and in the solid-state by means of the inear-polarized solid state IR-spectroscopy (IR-LD), UV-spectroscopy, TGA, DSC, and the positive and negative ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and the electronic spectra. The spectroscopic and theoretical data are compared with the structure of the first compound obtained by single crystal X-ray diffraction. The effect of Npy protonation on the optical and magnetic properties of a 4-acetaminopyridine is discussed.
Keywords: 4-Acetaminopyridine; protonated form; crystal structure; solid-state linear polarized IRspectroscopy; UV-spectroscopy; quantum chemical calculations1H- and 13C NMR; ESI MS; TGA and DSC
CFD modelling of two-phase liquid-liquid flow in a SMX static mixer
by Paulina Pianko-Oprych; Zdzisław Jaworski; (pp. 41-49).
The paper provides an overview of the application of Computational Fluid Dynamics tools for predicting transport processes in two-phase flow in a SMX static mixer. The overview is achieved by taking a brief look at factors: mesh generation, development of sub-models, post-processing including validation and quantitative verification of CFD results with experimental data. Two types of numerical approach were used in the simulations: the Reynolds averaged Navier-Stokes in the steady-state mode with the standard k-??turbulence model and Large Eddy Simulations in the unsteady mode. Both CFD techniques were applied to calculate flow velocities, pressure drop and homogenisation level in a SMX static mixer of the liquid-liquid mixture. The steady state drop size distribution was obtained by implementation procedure containing the population balance equation, where transport equations for the moments of the drop size distribution are solved and the closure problem is overcome by using the Quadrature Method of Moments.
Keywords: CFD; LES; QMOM; two-phase flow; liquid-liquid dispersion; SMX static mixer
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