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Three poly(p-benzamide)s bearing oligothiophene on the amide nitrogen atom through the alkylene spacer were prepared by the chain-growth condensation polymerization using initiator and base in the presence of chelating reagent. The polymerization was found to proceed in the controlled manner as confirmed by the GPC and NMR analyses. The UV and PL measurements indicated that the p-stacked interaction between oligothiophene chromophores depended on the structure of the repeating unit.
N-fused coronene analogs were prepared through thermal cycloaddition of perylene diimide with 1,2,4-triazoline-3,5-diones. Cycloaddition occurs twice, yielding mainly a bis-adduct under optimized reaction conditions using an oxidant. A perylene unit within a polyimide backbone transformed to a N-fused coronene unit with a wide absorption range from 600 to 850 nm and a low band gap of 1.3 eV.
The anionic ring-opening polymerizations of trans- and cis-1 were carried out using tert-BuOK as the initiator. The bulk polymerization of trans-1 proceeded without the elimination of CO2, but cis-1 gave no polymeric product. The thermal analysis indicates that trans-1 has extraordinarily large ring strain for five-membered cyclic carbonates, and is close to six-membered cyclic carbonates that have good ringopening polymerizability.
Series of novel PABIs have been obtained by the condensation polymerization of aromatic bifluorides with di(benzimidazolyl)benzenes via a C–N coupling reaction. PABI exhibited zigzag molecular chain structure with a high free volume fraction, and they showed relatively high glass-transition temperatures (Tg>240), good thermal stability with high decomposition temperatures (Td>450) and excellent solubility in organic solvents. The mechanical behavior of the PABI polymers suggested that they can be considered as a new class of high-performance polymers.
Control of the crystalline structure of poly(vinilydene fluoride) (PVDF) in a PVDF/poly(methylmethacrylate) (PMMA) blend were analyzed by varying the polymer blend ratio (PVDF/PMMA=60/40, 70/30 and 80/20 wt%) and the heat-treatment temperature (160–210 °C) just after the polymer melt. PVDF (form I) was limitedly obtained by heat treatment at 185 and 190 °C after blending PVDF/PMMA 70/30 wt%. The samples produced under other conditions indicated PVDF (form II). We assumed that PVDF crystalline structure became PVDF (form I) according to decrease of the crystallization rate by the highest compatibility between PVDF and PMMA.
New poly(etherimide)s (PEI) containing isopropylidene groups were synthesized and investigated. They are strong and tough polymeric materials, showing excellent solubility in common organic solvents and high thermal stability. The highest gas permeability and CO2/N2 selectivity was demonstrated by PEI containing hexafluoroisopropylidene unit. The correlations between chemical structure and physical and gas permeation properties were found to exist.
Novel electrical conductive carbon nanofibers were prepared by a combination of electrospinning and ion-beam irradiation techniques. Four types of polymer nanofibers, including polyimides (6FDA-6FAP and 6FDA-APPS), polysulfone and polyacrylonitrile, were prepared by the electrospinning method. The obtained polymer nanofibrous membranes were irradiated by Kr+ to give carbonized nanofibers. Electrical conductivities of the electrospun 6FDA-6FAP nanofibrous membrane reached up to ca. 10−1 S cm−1 with 1016 ion cm−2 of Kr+. The influences of starting polymers on electrical conductivity of the carbon nanofibers were studied by Raman and X-ray photoelectron spectroscopy analyses.
Static light-scattering techniques were utilized to study the micellization behavior of model asymmetric miktoarm star copolymers of the type AA′B, where A and A′ are polyisoprenes (PIs) and B is deuterated polystyrene (PS). In n-decane, a selective solvent for the PI blocks the comparison between linear PS–PI diblocks, symmetric PS(PI)2 and asymmetric PS(PI)(PI′) miktoarm stars, and confirms that the aggregation numbers (Nw) and, in general, the micellar properties can be manipulated at will, and that tailor-made micelles can be constructed changing the macromolecular architecture.
The effect of US on the shear viscosity of water-soluble polymer solutions was studied. The 43 kHz US significantly decreased the shear viscosity of the solutions. FT-IR spectra obtained during the US exposure showed that hydrogen bonds in the aqueous polymer solution could be broken. US absorption model was proposed to explain US absorption and the breakage in the hydrogen bonds. US effect influenced the condition of water solvation to the water-soluble polymers.
