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Thermo-responsive polymer hydrogels attract a great attention because of their unique behavior in response to changes in the thermal environment. It is related to metastable intermolecular interactions resulting in volume phase transitions (VPT). The hydration of poly(2-(2-methoxyethoxy)ethyl methacrylate) (PMEO2MA)-based materials was studied by Raman spectroscopy and further supported by density functional theory calculations. Hydrogels based on random networks prepared via radiationinduced free radical polymerization and cross-linking were compared with hydrogels withmore regular structure formed by atom transfer radical polymerization. Two types of regular networks were studied: bare one and decorated by linear dangling chains. It was found that both, the total bound water surrounding the polymer chains (~11 H2O per polymer unit) and accessibility of C=O groups for water molecules, are independent of topology of PMEO2MA network. Contrarily, network architecture strongly influences C=O-water complex stability, which decreases in a following order: regular bare network, irregular bare network, regular decorated network. It was also shown that the stability of C=O-water complex is correlated with VPT temperature in PMEO2MA hydrogels. These studies prove a key role of polymer hydration in its thermo-responsive properties. Copyright © 2016 JohnWiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A series of bifunctional heterogeneous catalysts based on SBA-15 supports modified with Zr, Nb and Mo species functionalized by aminopropyl siliceous species has been used in the Knoevenagel condensation. The results indicated that the acid–base synergetic effects of the centres present on these catalysts seem to have significant effect on the Knoevenagel condensation of benzaldehyde with active methylene compounds. Basic sites and Lewis acid sites play different roles depending on the methylene compound used in the Knoevenagel condensation. Depending on the chemical composition of the catalysts, the reaction can proceed on basic sites exclusively or on the pairs of acidic-basic centres. The nature of metal species strongly influences the activity in the Knoevenagel condensations but does not affect the selectivity. [ABSTRACT FROM AUTHOR]

Transition metals of group IV (Zr), group V (Nb), and group VI (Mo) were introduced into SBA-15 materials during the synthesis towards the production of metallosilicates, MSBA-15, to be used as supports for 3-aminopropyl-trimethoxysilane (APTMS), and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (3APTMS). The materials obtained were characterized by N 2 adsorption/desorption, XRD, TEM, ICP, XPS, UV-Vis, FT-IR and pyridine adsorption. The results indicated that the metals were loaded in the cationic state: Zr 4+ , Nb 5+ and Mo 6+ and preferentially located on the SBA-15 surface. The highest efficiency of metal loading in SBA-15 under the conditions used in this work was reached for molybdenum, whereas the highest metal content on the surface was observed for ZrS. The number of Lewis acid sites (LAS) changed in the following order: ZrS⪢; NbS > MoS, whereas their strength as follows: ZrS > NbS > MoS(HP). Zirconium containing material exhibited additionally BrØnsted acidity. The efficiency of propyl-amine incorporation changed according to the electron state of metals: Zr Nb Mo. The binding of propyl-amine to metal cations determined the amine stability. [ABSTRACT FROM AUTHOR]

Novel sulfur-silsesquioxane random copolymer (poly(S-r-POSS)) was synthesized via the radical reaction between liquid sulfur and octavinyl silsesquioxane. Particulate solid POSS was dispersed in molten sulfur and heated in order to initiate the free radical reaction (inverse vulcanization). The appearance of new C–S bonds along with the disappearance of C=C bonds from vinyl groups was confirmed by Raman and FTIR spectroscopy. Moreover, the formation of saturated single C–C bonds from the reacting vinyl groups was revealed by FTIR. Microhomogenity of the copolymer was analyzed by means of SEM-EDS mapping and its thermal properties were studied using the TG-DSC method. After the extraction of free unreacted sulfur and POSS the copolymer exhibits porous micromorphology promising for application in lithium–sulfur batteries or heavy metals ion capturing. Highlights Synthesis of silsesquioxane-sulfur hybrid copolymer via inversed vulcanization Highly porous cross-linked morphology Potential utilization for lithium–sulfur batteries or heavy metals ion capturing [ABSTRACT FROM AUTHOR]

Electron beam irradiation of 2-(2-methoxyethoxy)ethyl methacrylate and ethylene glycol dimethacrylate mixtures leads to the formation of cross-linked structures that exhibit a gradient of cross-link density, as demonstrated by gel fraction, swelling and Differential Scanning Calorimetry analysis. The reason for observed phase separation is formation of the high molecular weight clusters and its precipitation before gelation dose. This effect can be controlled/influenced by absorbed dose and cross-linker concentration. [ABSTRACT FROM AUTHOR]

Abstract: The gradient (“transient”) systems are required for many biomedical applications, especially if the materials with different properties are to be joined without strong internal stresses. In this paper one step, radiation-induced synthesis of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate with gradient in crosslink density, has been presented. The influence of the monomer composition and synthesis procedure (irradiation dose and conditioning temperature) on the general properties of prepared gels has been discussed. It has been found that the properties of particular sections of the gel sample do not result from the differences in chemical structure, but from significantly different morphology. The explanation of the mechanism leading to gradient behavior of obtained gels has been proposed. The chemical structure of obtained products and morphology of synthesized hydrogels as well as general properties of products have been analyzed. [Copyright &y& Elsevier]