Materials Literature
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The variation of the pore structure of styrene–divinylbenzene (S–DVB) copolymer beads with the drying conditions was investigated. Macroporous S–DVB copolymer beads with various DVB contents were prepared in the presence of toluene-cyclohexanol mixtures as a diluent. It was found that the pores of 101-nm radius, corre…
This article describes the crystallization behavior of polypropylene (PP) in the presence of a crystallizable polymer, namely, nylon 6, in the binary blend of PP/nylon 6 in the composition range from 0 to 30 wt % of nylon 6 content in the blend. The crystallization behavior was studied through variation of the crystal…
Using direct polymer reaction of poly(styrene-co-maleic anhydride) (SMA), a synthesis of copolymer of styrene and N-aryl succinimide (SMI) has been investigated. SMI copolymers were synthesized from SMA copolymers by a concerted two-step reaction, which consisted of the condensation reaction (step 1) of SMA with aroma…
In the present article a series of low-density polyethylene (LDPE) blends with different amounts of fatty esters of amylose and starch, were prepared in a Haake-Buchler Reomixer. The tensile as well as the dynamic thermomechanical (DMTA) properties of the blends were measured. It was found that as the amount of the es…
We studied styrene and fluoroalkylfumarate (FAF) copolymers and their surfaces by means of contact angle measurement and X-ray photoelectron spectroscopy (XPS). The surfaces of the copolymers were very hydrophobic (even with a small amount of FAF) because of the concentration of FAF segments at the surface. The hydrol…
Low-density polyethylene (LDPE) film was chemically modified by chromic acid treatment to generate polar groups on the surface. The film samples were etched by chromic acid with variation of temperature at a constant time (30 min) and variation of time at a constant temperature (room temperature = 26°C). The variation…
Crosslinked ethylene–vinyl acetate (EVA) copolymers with VA content of 28% by weight were prepared by a two-step method by evenly dispersing the crosslinking agent (dicumyl peroxide) into the EVA matrix and then crosslinking at elevated temperatures. The crosslinking features of the samples were analyzed by Soxhlet ex…
We report a new technique for fabricating metallic electrodes on insulating substrates with separations on the 1 nm scale. The fabrication technique, which combines lithographic and electrochemical methods, provides atomic resolution without requiring sophisticated instrumentation. The process is simple, controllable,…
The crystallization process and crystal morphology of poly(ethylene terephathalate) (PET)–clay nanoscale composites prepared by intercalation, followed by in-situ polymerization, have been investigated by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), dynamic scanning calorimetry (DSC)…
The preparation of nylon 6/clay nanocomposites by a melt-intercalation process is proposed. X-ray diffraction and DSC results show that the crystal structure and crystallization behaviors of the nanocomposites are different from those of nylon 6. Mechanical and thermal testing shows that the properties of the nanocomp…
Time-resolved synchrotron small-angle X-ray scattering (SAXS) measurements during isothermal crystallization of an associated polymer blend, consisting of one-end-aminated polystyrene (APS) and one-end-sulfonated poly(ethylene glycol) (SPEG), have been performed. Two different methods of sample preparations were used.…
Resonance Raman and UV-visible absorption spectra show that nickel(II) microperoxidase-11 (NiMP-11) is four-coordinate in aqueous solution in the pH range from 1.0 to 13.0. In aqueous solutions of NiMP-11 in the absence of cetyltrimethylammonium bromide (CTAB), NiMP-11 is aggregated. In CTAB micellar solutions, where…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTShape-Selective Recognition and Self-Assembly of mm-Scale ComponentsInsung S. Choi, Ned Bowden, and George M. WhitesidesView Author Information Department of Chemistry and Chemical Biology Harvard University, 12 Oxford Street Cambridge, Massachusetts 02138 Cite this: J…
We report the novel cooperative properties of a complex obtained by self-assembling in solution a tetracationic cobalt porphyrin, Co II P 4+, and a tetraanionic sulfoaluminum phthalocyanine, Al III Pc 4- . In the ground state, the complex displays a charge transfer character, Co II-δ P 4+ /(Al III Pc 4- ) +δ, and the…
The cluster formation in nucleating hen egg white lysozyme−NaCl solutions was studied by simultaneous static and dynamic light scattering. Angular dependence measurements of the total scattered intensity and of the average cluster diffusion coefficient revealed the appearance of pronounced structure factor peaks at th…
Atomistic computer simulation techniques are used to investigate the defect properties of the La 2 Ni 1 - x M x O 4 (M = Mn, Fe, Co, Cu) layered perovskite which are related to the mode of operation of the catalyst. The theoretical techniques are based upon efficient energy minimization procedures and Mott−Littleton m…
Adsorption of the phosphate groups on a silica surface is investigated by ab initio calculations of hydrogen-bond complexes of dihydrogen and dimethyl phosphate anions with orthosilicic acid. It is found that the phosphate groups can form strong hydrogen-bonded complexes with the silanols of the silica surface with st…
In polyisocyanates composed only of randomly distributed ( R ) and ( S ) units, the chiral optical properties of the polymer are far out of proportion to the enantiomeric excess of the monomers. This highly disproportionate relationship, which arises from a majority-rule effect among these enantiomeric units on the he…
Single crystals of gallium tris(8-hydroxyquinoline) (Gaq3) were obtained. The X-ray diffraction study showed that the Gaq3 solid is an extensive three-dimensional framework which is constructed from the intermolecular π−π stacking and hydrogen-bonding interactions.
The isocyanides 3-(4-pyridylethynyl)phenylisocyanide, 3, 4-(4-pyridylethynyl)phenylisocyanide, 6, 2,6-diisopropyl-4-(4-pyridylethynyl)phenylisocyanide, 9, and 2,6-diisopropyl-4-(4-pyridyl)phenylisocyanide, 11, were prepared. With PdI(2) and PtI(2), these isocyanides form the complexes trans-[MI(2)(CNR)(2)], 12-19 (M =…