Original Article in 2010

Fluorescent Fe(II) metallo-supramolecular polymers (Fe(II)-MEPEs) are synthesized through complexation of Fe(II) ions with new bisterpyridine ligands bearing triethylene glycol (TEG) chains at the ortho-position of pyridine rings. Although Fe(II) ion is known as a quencher of fluorescence, Fe(II)-MEPE containing TEG chains shows nearly a threefold higher retention of fluorescent properties compared with unsubstituted analogs.

Block copolymerization of cellulose and styrene was carried out by ATRP. Macroinitiators were prepared from three types of cellulose (DP=20, 50, 250). The resulting copolymers were characterized by ¹H NMR and SEC. The miscibility of the immiscible cellulose/PS blend was improved by the addition of block copolymer.

Coupling polymerizations of 2,3-dibromo-N-substituted maleimide (DBrRMI) (R=benzyl (DBrBnMI), phenyl (N-phenyl-2,3-dibromomaleimide (DbrPhMI)), cyclohexyl (N-cyclohexyl-2,3-dibromomaleimide), n-hexyl (N-n-hexyl-2,3-dibromomaleimide) and n-dodecyl (N-n-Dodecyl-2,3-dibromomaleimide, DBrDMI)) were carried out using palladium or nickel catalysts. Number-average molecular weights (M_n) of poly(RMI-alt-Ph) or poly(RMI-alt-TP) obtained by Suzuki–Miyaura cross-coupling polymerizations of DBrRMI with benzene-1,4-boronic acid (PhDB) or 2,5-thiophene diboronic acid (TPDB) were 680–1270 by GPC analyses. In contrast, coupling polymerizations of DBrRMI with 1,4-diiodobenzene gave random poly(RMI-co-Ph). Poly(RMI-co-Ph)s exhibited higher thermal stability than monomer and poly(RMI-alt-Ph). Copolymers showed strong photoluminescence from yellow to light blue color in THF.

A new host material, PCNVTPA, was successfully synthesized for high-performance iridium complex light-emitting devices. Efficient energy transfer was observed from the host PCNVTPA to the guest Ir complex. Single-layer phosphorescent electroluminescent devices of ITO/PEDOT: PSS/PCNVTPA:Ir complexes/Ca:Al exhibited maximum luminance (2899cdm⁻²) and luminance efficiency (8.84 cd A⁻¹), respectively, which were much higher than those of PVTPA. Such an improvement was probably due to more efficient hole trapping in Ir complexes or better electron injection from the lower energy levels of PCNVTPA.

A series of new 1,2,3-triazole-containing polytriazoleimides was synthesized by the copper-catalyzed click polymerization of azide–alkyne cycloaddition. The click polymerization of imide-containing dialkynes with the diazide could produce new polymers with imide and triazole units in the main chain.The polytiazoleimides obtained, with inherent viscosities of 0.39–0.58 dl g⁻¹, had good solubility in polar solvents and could be cast into transparent, tough and flexible films. These novel polytriazoleimide films exhibited good thermal stability and mechanical properties

The variations in the free volume and the thickness of the active polyamide layers of the composite membranes were obtained by positron annihilation spectroscopy (PAS) experiments, in which a variable monoenergy slow-positron beam was used. The data on Doppler broadening Sparameters vs annihilation radiation energy spectra showed that the active MPDASA-TMC layer of the composite membrane had a lower free volume and was thinner than the active MPDA-TMC layer. This result corresponded well with that from the pervaporation performance of TFC polyamide membranes.

Delaminated PS/magadiite and PPE-PS/magadiite nanocomposites were successfully prepared by a combination of surface-initiated polymerization and a melt-blending process. For a series of PS/magadiite composites, their PHRR values decreased with improvements in magadiite dispersion. Exfoliated PS/magadiite nanocomposites exhibited the lowest PHRR, forming seamless and strong solid residues.

Addition effects of a series of N-alkyl-substituted methylimidazolium salts ([CnMim][X]) on the mesophase structure and LCST-type phase-separation behavior, and the ensuing optical properties of concentrated hydroxypropyl cellulose (HPC) aqueous solutions, were investigated by spectrophotometry and complementary X-ray diffractometry. Salted HPC solutions exhibited distinct shifts in both the cholesteric pitch and the cloud point, relative to the nonionic reference. Discussion of the observations took into consideration the differences in the N-alkyl structure and amphiphilic nature between the imidazolium varieties, as well as the difference in a socalled chaotropic strength between the anions used.

A crown ether–ammonium salt-type rotaxane monomer was synthesized in a high yield using dibenzo-24-crown-8-ether and sec-ammonium salt having a hydroxy terminal by means of an end-capping reaction with an ethynyl benzoic acid. Its N-acetylated derivative was also synthesized as a neutral monomer. Novel side chain-type polyrotaxanes, that is, ammonium-type and neutral polyphenylacetylenes tethering rotaxane moieties in side chains with high molecular weights were obtained in high yields by polymerizations with an Rh catalyst. N-acetylation of the rotaxane moieties of the ammonium salt-type polymer afforded a red-colored neutral polymer showing red-shifted UV-vis absorption due to the conjugated main chain, according to the change in distance between the wheel component and the polyacetylene main chain.

Water-soluble pachyman (WSP) was prepared by enzymic hydrolysis of pachyman extracted from Poria cocos sclerotium. Two WSP fractions, WSP-1 and WSP-2, both of which were β-(1→ 3)-D-dextran, were separated by SephadexG-100 from WSP. The figure displays the Infrared analysis of pachyman, water-soluble pachyman, WSP-1 and WSP-2.

A new kind of modified bismaleimide resins made from 4,4'-bismaleimidodiphenylmethane, hydrogen silsesquioxane, dipropargyl ethers of bisphenol A, dipropargyl ethers of hexafluorobisphenol A, dipropargyl ethers of 4,4'-dihydroxydiphenyl ether and dipropargyl ethers of resorcinol, with good heat resistance and processing properties for advanced composites, was developed. The cured resins showed a high glass transition temperature (Tg) (>330 °C) and a high thermal decomposition temperature (Td5) (>400 °C).

Calcium alginate gels containing hydroxyapatite were prepared in one step and evaluated with regard to pH dependence and electrochemical property for applying to drug carriers. The composite gels immersed in a pH indicator solution changed its color by applying voltage. By these results, it was revealed that pH alteration of composite gels occurred by electro-osmosis and electrophoresis. Swelling and shrinking of the composite gels were controlled by external stimuli of pH and voltage and the content of hydroxyapatite.

LbL multilayer properties such as thickness, conformation of the peptide component, homogeneity and periodicity of nanoparticle layers were significantly affected by the kind of polycations. The combination of anionic PLGA-coated gold nanoparticle and cationic PLL induced a β-sheet formation, which enables the fabrication of a homogeneously well-packed gold nanoparticle multilayer without aggregation.

Micrometer-sized, monodisperse polystyrene (PS)/poly(styrene-cosodium styrene sulfonate) (P(S-NaSS))/poly(n-butyl methacrylate)(Pn-BMA) composite particles having a ‘golf ball-like’ shape were prepared by seeded dispersion polymerization of n-BMA with PS-core/P(S-NaSS)-shell seed particles in the presence of dodecane droplets. The effect of the P(S-NaSS)-shell properties of seed particles on the formation of golf ball-like particles was investigated. We clarified that golf ball-like particles could be obtained by proper selection of the hydrophilicity and molecular weight of the shell moiety.

Conformational changes of sPP during melting and isothermal crystallization process were studied by IR and 2D-correlation analysis. The absorption intensity of the band at 963 cm⁻¹ (amorphous) increases earlier than that of the band at 978 cm⁻¹ (shorter helix), and that of the band at 867 and 812cm⁻¹ (crystalline helix). We found that partial sPP chains in amorphous component change their conformation first and then adjust their local conformations into short helix, and then crystallization occurs.

Aromatic sulfonate esters as acid amplifiers were introduced into a photosensitive polyetherimide system on the basis of reaction development patterning (RDP), composed of polyetherimide and a diazonaphthoquinone (DNQ) as a photosensitive agent. The resulting chemically amplified RDP (CARDP) system enabled positive-tone pattern formation with a reduced amount of the photosensitive agent and exposure dose. In particular, the use of 2SCE resulted in the formation of clear patterns with 5wt% of the photosensitive agent with a sensitivity of 125mJ/cm². The patterns prepared by CARDP showed good thermal properties.

Three C₂₁-based reactive polyamides with various amine values as epoxy-curing agents were synthesized from tung oil and different polyamines. It was found that the cured materials were superior to those cured by widely used C₃₆-based polyamides with regard to mechanical properties. The glass transition temperatures of three cured C₂₁-based polyamides were found to be higher than that of C₃₆-based polyamides. The curing kinetics were studied and nonisothermal DSC curves show a good agreement with theoretically calculated ones.

Transparent and homogeneous hybrids were synthesized from poly(methyl methacrylate) (PMMA) and aqueous dispersed zirconium oxide nanocrystals (ZrO₂-NCs) with a coupling agent, 3-(methacryloxy)propyltrimethoxysilane (MPTS). The covalent bonding between PMMA- and MPTS-modified ZrO₂ nanocrystals is crucial to obtain nanoscale dispersed hybrid materials. The hybrid films retained good optical transparency compared with that of PMMA/ZrO₂ blend composites and will be promisingly applied for optical functional materials and coatings.

Direct condensation polymerization of N-alkylated aminobenzoic acid was carried out using hexachloroethane, triphenylphosphine and pyridine as condensation reagents. Pale-yellow, fibrous polymers (PABA_n, where n is the number of carbon atoms of the side chain) were obtained in 46–87% yields with an inherent viscosity of 0.30–1.18 per 100ml g⁻¹ (sulfuric acid, 30 °C). DSC analysis and powder X-ray scattering of polymer samples indicated that PABA_n with Me, Pr, Bu, Pe and Ste as side chains were crystalline polymers. X-ray scattering profiles indicated that PABA_n with n=0, 3, 4 and 5 crystallized in an orthorhombic lattice, whereas PABA₁ crystallized in a monoclinic lattice. PABA₁₇ crystallized with hexagonal packing at the long side chain with an interplanar spacing of 4.2Å.