Research articles

Epoxy resins, which are obtained by the curing reaction of epoxy- and amine-compounds mixture, have been often utilized in contact with metals. We herein report on the chemical composition of the epoxy resin in close proximity to the copper interface on the basis of a non-destructive method. The concentration of the amine component in the interfacial region was 2-fold higher than that in the bulk, and the interfacial enrichment extended over at least 10 nm.

Solvent-free base-catalyzed CO₂ fixation into polymers having 2-pyridyl group-substituted propargylamine moieties in the main and side chains was achieved under atmospheric CO₂ condition. The reactivity of the polymer films was improved by the introduction of pendant tertiary amine moiety.

Ethylene polymerization with bis(diethylamido){di(3-methylindol-2-yl)phenylmethane}titanium (1) was examined using modified methylaluminoxane (MMAO) as an activator. The activity of the 1/MMAO catalyst system was low (16.3 kg of polyethylene (PE)/mol of Ti•h), but pretreatment of 1 with ClSiMe₃ followed by activation with MMAO improved the activity up to 154 kg of PE/mol of Ti•h. The obtained PEs are all monomodal by size exclusion chromatography and have linear structures by NMR spectroscopy. The 1/ClSiMe₃/MMAO catalyst system was also active for ethylene/1-octene copolymerization (90 kg of copolymer/mol of Ti•h).

Irrespective of the degree of polymerization, the molecular mobilities of the 2-hydroxyethyl methacrylate (HEMA) moieties are smaller than those of the 2-methoxyethyl acrylate (MEA) moieties. Preventing the polar functional groups of the foulants and materials from forming a hydrogen-bonding network is important to enhance the mobilities of the molecular chains of non-ionic polymeric materials. We speculate that enhancing the mobilities of the molecular chains is key to improving blood compatibility.

UV light irradiation causes the unexpected structural transition from core–shell to Janus in droplets consisting of a poly(4-butyltriphenylamine) (PBTPA)/poly(methyl methacrylate) (PMMA) blend solution. We obtained a phase-separated structure formed by the evaporation of the solvent from polymer solution droplets dispersed in an aqueous solution containing a surfactant. It was also found that the transition was caused by UV light with a wavelength of 365 nm, which is mainly absorbed by PBTPA, indicating that this phenomenon is triggered by PBTPA.

Cellulose oligomers were synthesized via cellodextrin phosphorylase-catalyzed reactions using α-D-glucose 1-phosphate monomers and D-glucose primers. The products prepared at relatively high primer concentrations self-assembled into highly grown nanoribbon network structures. The nanoribbons were composed of cellulose oligomers with degree-of-polymerization (DP) values of 8-9 with certain degrees of DP distribution and displayed the cellulose II allomorph. A formation mechanism for the unique nanostructures was proposed based on analyses of reaction time-dependent differences of the product solutions.

For THF solutions of an optically active helical poly[3,5-bis(hydroxymethyl)phenylacetylene] derivative bearing a biphenyl group, photoexcitation of the terphenyl moiety at 300 nm led to photoluminescence at 390 nm. On the other hand, the photoluminescence resulting from excitation at 280 nm caused dual emission at 310 and 390 nm, whose intensities were tuned by the polar-solvent stimuli which induced the collapse of the intramolecular stack structure of the side groups, and the change in the emission wavelength accompanied disappearance of the optical activity.

Novel high-refractive-index materials consisting of poly(thiophosphonate)s were developed by the polycondensation of phenylthiophosphonic dichloride with various bisphenols. These polymers exhibit excellent thermal stability (T_d5 > 420 °C), moderate to high glass transition temperatures (117–204 °C) and high transparency in the visible light region. Furthermore, they achieve high refractive indices of 1.626–1.687 owing to the highly polarizable sulfur and phosphorous atoms in their backbones and relatively high Abbe numbers of 21.3–27.5.

An efficient method to decrease dielectric constant (ɛ) of poly(2,6-dihydroxy-1,5-naphthylene) (PDHN) by introducing bulky alkyl side chains was reported. Poly(2,6-dialkoxy-1,5-naphthylene)s (PDANs) were prepared by the O-alkylation of PDHN with alkyl halides. The ɛ values of PDANs at 10 GHz decreased as the length and size of side chains increased. Especially, PDCHMN exhibited the lowest dielectric constant (ɛ = 2.29). The ε value results were also supported by refractive index measurement.