A novel series of soluble and heat-resistant copoly(arylene ether phenyl-s-triazine)s (PAEPs) have been prepared for their potent utilities as structural coatings, high-temperature membranes or adhesives. The copolymers have been synthesized via the nucleophilic displacement polymerization of 2,4-bis(4-fluorophenyl)-6-phenyl-1,3,5-triazine (BFPT) with various ratios of hydroquinone (HQ) and resorcinol (RS). A key feature of these copolymers is the incorporation of multiply meta-ether linkages in the polymer chain, which results in an improvement in the solubility of poly(arylene ether phenyl-s-triazine)s in common organic solvents (e.g., N,N’-dimethylacetamide, N,N’-dimethylformamide, N-methyl-2-pyrrolidinone). The new random copolymers exhibit high glass transitions exceeding 241 °C and excellent thermal and thermo-oxidative stabilities associating with decomposition temperatures for 5% mass-loss in excess of 531 °C. These copolymers can be easily cast into tough, clear and creasable films and exhibit good mechanical properties. All copolymers are amorphous except PAEP9010 as evidenced by WAXD. Their solubility increases with an increase in meta-ether linkage content in the polymer backbone, while the crystallinity and the overall thermal stability appear to decrease slightly. This kind of phenyl-s-triazine-based poly(arylene ether) copolymers may be considered a good candidate for using as high-performance polymeric materials. 相似文献
The reactivity of Lewis acidic ionic liquids for the acylation of acenaphthene to 3,6-dibenzoylacenaphthene was investigated.
Ionic liquids of different alkyl chain length and metal chloride were synthesized and tested for the reaction to discuss the
effects of Lewis acidity of the ionic liquid on the alkylation. Pure 3,6-dibenzoylacenaphthene was obtained and the structure
of 3,6-dibenzoylacenaphthene was identified by GC/MS, FT-IR and 1H NMR spectra. [Emim]C1/A1C13 ionic liquid was found to be the most active catalyst in the acylation. The yield of 3,6-dibenzoylacenaphthene was up to
89.6% and the selectivity towards 3,6-dibenzoylacenaphthene was up to 92.2%. The experiment shows that [Emim]Cl/AlCl3 can be used as both catalyst and solvent, it is reusable and environmentally friendly for the preparation of 3,6-dibenzoylacenaphthene. 相似文献
The solids content and gelation time of aqueous germanate solution were examined in this work. Samples of 5, 10 and 20 mol%
Mn doped Ge were prepared by using the aqueous germanate solution as a liquid Ge precursor. No second phase such as Mn5Ge3 was detected in the 5 and 10 mol% Mn doped samples, implying that Mn ions were uniformly diluted into the Ge host matrix.
The 5 and 10 mol% Mn-doped Ge samples exhibit room-temperature ferromagnetic behaviors that are likely originated from the
RKKY (Ruderman–Kittel–Kasuya–Yosida)-like interaction between the localized Mn ions in the Ge matrix. Therefore, the aqueous
germanate solution can be an alternative sol–gel precursor for preparation of the MnxGe1−x diluted magnetic semiconductors (DMSs). 相似文献
Stable complexes : An extremely air‐stable μ2‐hydroxy‐bridged binuclear hafonocene perfluorooctanesulfoante complex shows high catalytic efficiency in Lewis acid‐catalyzed reactions, such as esterification, Friedel–Crafts acylation, the Mukaiyama aldol reation, and the allylation of aldehyde (see scheme).