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The crosslink density distribution in gels known as the spatial gel inhomogeneity has been investigated in poly(acrylic acid) (PAAc) gels with the static light scattering measurements. PAAc gels were prepared at a fixed chemical crosslink density but at various initial monomer concentrations. The gels were characterized by swelling and elasticity tests as well as by light scattering measurements....
In this communication, we report for the first time the synthesis of a new electroactive poly(aryl ether ketone) derived from the phenyl-capped aniline tetramer. The general properties are studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The polymer has high serving temperature and good thermal stability. And its chemical oxidation process was studied by UV–Vis...
The three-dimensional (3D) model of the 3-hydroxykynurenine transaminase (3-HKT) is constructed based on the crystal structure of the alanine-glyoxylate aminotransferase (EC 2.6.1.44, PDB code 1VJO) by using InsightII/Homology module. With the aid of the molecular mechanics and molecular dynamics methods, the last refined model is obtained and further assessed by Profile-3D and ProStat, which confirm...
In this work, interpenetrated polymer networks (IPN) composed of alginate-Ca 2+ and poly(N-isopropylacrylamide), PNIPAAm, were synthesized and their water uptake capability was measured at temperatures from 25 to 40°C and compared to that of pure alginate-Ca 2+ hydrogels without PNIPAAm. A sharp decrease of WU was observed when IPN hydrogels are heated above 32–33°C. The phenomenon...
Here, the effect of concentration on the morphology and dynamic behavior of polymethylmethacrylate/polystyrene (PMMA/PS), for PS with two different molecular weight, and polymethylmethacrylate/polypropylene (PMMA/PP) blends was studied. The blends concentrations ranged from 5% to 30% of the dispersed phase (PS or PP). The dynamic data were analyzed to study the possibility of inferring the interfacial...
The synthesis of hydroxy-terminated poly(2,2-substituted-1,3-propylene oxide) polyoxetane telechelics and co-telechelics bearing semifluorinated (–CH 2 OCH 2 (CF 2 ) n CF 3 ) and functional bromomethyl pendant groups is reported. Characterization utilized 1 H NMR spectroscopy, temperature modulated DSC (MDCS), and gel permeation chromatography (GPC)...
Two kinds of polyelectrolyte: polyacrylic acid (PAA) and poly(sodium 4-styrenesulfonate) (PSS), were grafted onto the convex surfaces of multiwalled carbon nanotubes (MWNTs) by surface-initiating ATRP (atom transfer radical polymerization) from the initiating sites previously anchored onto the convex surfaces of MWNTs. The grafted polyelectrolyte can be efficiently quantified by the feed ratio of...
The isothermal crystallization kinetics and the melting behavior of block copolymers of poly(ethylene oxide) and poly(1,2-butylene oxide) were studied by means of differential scanning calorimetry and rheometry to test the validity of rheological methods. The copolymers had different block lengths (hence different melt structures) and different block architectures (diblock EB and triblock EBE and...
In order to develop a casting resin for precision molding, a curing method without shrinkage during the polymerization was achieved by the double ring-opening addition reaction of spiro orthoester (SOE) and acid chloride using cationic catalysts. Tetraphenylphosphonium halides (TPPXs) were found to be effective catalysts for the reaction. The catalytic reaction of SOE with acid chloride proceeded...
This paper reports the photo- and electroluminescence studies of emitting species of one of the first reported blue emitters, the conjugated–non-conjugated multi-block copolymer, poly[1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-3,5-dimethoxy-1,4-phenylene]. Because the conjugation length of the emissive center is very well defined (two and half phenylene–vinylene...
Soy based bioplastic and pineapple leaf fiber ‘Green’ composites were manufactured using twin-screw extrusion and injection molding. Thermal properties, mechanical properties and morphology of the green composites were evaluated with Dynamic Mechanical Analyzer (DMA), United Testing System (UTS) and Environmental Scanning Electron Microscopy (ESEM). The effects of fiber loading and polyester amide...
Isothermal crystallization behavior of poly(ethylene-co-hexene) (PEH) and the 50/50 blend (H50) of PEH with amorphous poly(ethylene-co-butylene) (PEB) was studied by time-resolved synchrotron simultaneous small-angle X-ray scattering/wide-angle X-ray diffraction (SAXS/WAXD) techniques and optical microscopy (OM). The X-ray study revealed the changes of structural and morphological variables such as...
A detailed study of the structure–property relationships for nanocomposites prepared using melt processing techniques from a sodium ionomer of poly(ethylene-co-methacrylic acid) and a series of organoclays is reported. Transmission electron microscopy, X-ray scattering, stress-strain behavior, and Izod impact analysis were used to evaluate the nanocomposite morphology and physical properties. Four...
One of the important factors, which determine the concentration of moisture that a polymer will absorb, is the effect of non-random mixing whereby water-clustering is said to occur. The Flory–Huggins theory cannot predict the isotherms observed for highly polar polymers since the theory assumes complete random mixing. The complementary model of Brown [Brown GL. In: Rowland SP, editor. Water in polymers...
Dielectric properties of three curing epoxy resin systems at an industrial microwave frequency, 2.45GHz, were measured over a temperature range lower than the cure temperature. Extent of cure, which is determined by DSC, is used to describe the progress of the polymerization. It has been found that, normally, the real and the imaginary part of the complex dielectric constant increased with temperature...
The topological sub-structural molecular design (TOPS-MODE) approach has been applied to the study of mutagenic properties in a heterogeneous set of dental monomers. A model able to describe close to 90% of the experimental variance in the values for mutagenic activity of 41 dental monomers through genetic algorithm was developed with the use of the mentioned approach. Also, a study for the determination...
A (star polystyrene)-block-(linear polyisoprene)-block-(star polystyrene) copolymer, (S) n I(S) n , was prepared. The star polystyrene was produced via anionic polymerization of polystyrene macromonomers each containing an unsaturated double bond (vinyl) at the chain end. This vinyl-terminated polystyrene macromonomer (SSTM) was obtained beforehand via the synthesis of a living polystyrene...
This third paper in this series regarding structure and dynamics of the polyurethane-based membranes studied with TEMPO spin probe presents the results of the ESR measurements performed to characterise mobility of segments in the permeable regions of the membranes. The variations of the spin probe motions with temperature have been analysed for the series of polyurethanes (PU) differing in molecular...
To prepare polymer-grafted nano-sized silica with hydrophilic core and hydrophobic shell and with higher percentage of grafting, the postgraft polymerization of vinyl polymers onto hyperbranched poly(amidoamine)-grafted (PAMAM-grafted) nano-sized silica initiated by the system consisting of Mo(CO) 6 and terminal trichloroacetyl groups of PAMAM-grafted silica was investigated. The introduction...
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