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71.
Yasushi Ishido Arihiro Kanazawa Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2014,52(9):1334-1343
Significant structural effects of enol ether monomers were demonstrated in cationic alternating copolymerizations with benzaldehyde derivatives (BzAs). α‐Methyl, β‐methyl, β,β‐dimethyl, and cyclic enol ethers were copolymerized with BzAs by the EtSO3H/GaCl3 system with 1,4‐dioxane in toluene at ?78 °C. β‐Methyl and cyclic monomers, β‐monosubstituted compounds, induced copolymerizations with BzAs, some of which were well controlled to yield alternating copolymers with controlled molecular weights (MWs) and narrow MW distributions. Conversely, an α‐methyl vinyl ether (VE) did not copolymerize with BzAs at all, probably due to its high reactivity and unfavorable ketal linkage formations. In addition, a β,β‐dimethyl VE underwent only cyclotrimerizations because of its larger steric repulsion. The product alternating copolymers, especially those with cyclic units, exhibited improved thermal properties compared to those with simple VEs units. Under appropriate conditions, the alternating copolymers selectively degraded into the corresponding cinnamaldehyde derivatives by acid hydrolysis. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1334–1343 相似文献
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Hiroyuki Yanagisawa Tetsuya Tachikawa Sadahito Shim Osamu Wada 《Applied biochemistry and biotechnology》1990,23(1):1-13
In order to investigate relationships between human carcinogenesis and dietary carcinogens, one hybridoma cell line secreting a monoclonal antibody against 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), a dietary carcinogen, was produced by fusing splenocytes from Balb/c mice immunized with IQ-Lysine(Lys)-Ascaris protein conjugate. The subclass of monoclonal anti-IQ antibody was determined by double immunodiffusion using culture medium and identified as IgG1. Monoclonal anti-IQ antibody was purified from ascites fluids of Balb/c mice with affinity chromatography on Protein A-Sepharose CL4B and analyzed concerning its cross-reactivity and sensitivity with RIA. Finally, we showed that our monoclonal antibody recognized IQ, 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ) and several beta-carbolines more intensely and that the sensitivity to IQ was 23 nmol in 50% displacement. 相似文献
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The living cationic polymerization of vinyl ethers was carried out with organoaluminum compounds in the presence of various types of esters and ethers (cyclic and acyclic), to find out the suitable added bases available for the living polymerization. The effects of the basicity and steric hindrance of added bases were investigated in detail. On the basis of these results, a fast living polymerization system was realized. To synthesize water-soluble polymers such as thermally-induced phase separating polymers and polyalcohols with well-defined polymer structure, the living polymerization of various vinyl ethers was examined. The aqueous solution of living poly(vinyl ethers) having oxyethylene units exhibited a quite sensitive (ΔTps=0.3–0.5°C) and reversible phase separation on heating and cooling. The effects of polymer structures (pendant substituent, polymer sequence, molecular weight, and MWD) on the phase separation behavior were investigated. PVA and block copolymers containing PVA units with a narrow MWD were also prepared via living cationic polymerization of vinyl ethers and a deprotection reaction. 相似文献
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Shojiro Kaita Takako Otaki Eiichi Kobayashi Sadahito Aoshima Junji Furukawa 《Journal of polymer science. Part A, Polymer chemistry》1997,35(13):2591-2597
The polymerization of polar monomers such as methyl methacrylate (MMA), methyl acrylate (MA), methacrylonitrile (MAN), and acrylonitrile (AN) was carried out with gadolinium-based Ziegler–Natta catalysts [Gd(OCOCCl3)3-(i-Bu)3Al-Et2AlCl] in hexane at 50°C under N2 to elucidate the effect of the monomer's HOMO(highest occupied moleculor orbital) and LUMO (lowest unoccupied molecular orbital) levels on the polymerizability. In the case of homopolymerization, all monomers were found to polymerize and the order of relative polymerizability was as follows: MM > MA > MAN > AN. On the other hand, the result of copolymerization of St with MMA shows that the values of the monomer reactivity ratios are r1 = 0.06 and r2 = 1.98 for St(M1)/MMA(M2). The monomer reactivity ratios of styrene (St), p-methoxystyrene (PMOS), p-methylstyrene (PMS), and p-chlorostyrene (PCS) evaluated as r1 = 0.55 and r2 = 1.07 for St(M1)/PMOS(M2), r1 = 0.38 and r2 = 0.51 for St(M1)/PMS(M2), and r1 = 0.72 and r2 = 1.25 for St(M1)/PCS(M2) were compared with those for St(M1)/MMA(M2). The copolymerization behavior is apparently different from the titanium-based Ziegler—Natta catalyst, regarding a larger monomer reactivity ratio of PCS. The lower LUMO level of PCS and MMA may enhance a back-donation process from the metal catalyst, therefore resulting in high polymerizability. These results are discussed on the basis of the energy level of the gadolinium catalyst and the HOMO and LUMO levels of the monomers. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2591–2597, 1997 相似文献
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Ishida M Sakai H Sugihara S Aoshima S Yokoyama S Abe M 《Chemical & pharmaceutical bulletin》2003,51(11):1348-1349
Thermo-sensitive copolymer consists of poly(2-ethoxyethyl vinyl ether) and poly(hydroxyethyl vinyl ether) (EOVE200-HOVE400), whose sol-gel transition temperature was 20.5 degrees C, was synthesized and its applicability to a drug delivery system was examined. Vitamin E (VE) was enclosed in EOVE200-HOVE400 and the release of VE was measured by varying the temperature 10<-->30 degrees C. There was no release of VE from EOVE200-HOVE400 at 30 degrees C, while VE was released when the temperature was reduced to 10 degrees C. 相似文献
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Eiichi Kobayashi Yasuhide Akiba Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》1994,32(9):1609-1617
A novel addition polymerization of 1,4-benzenediselenol (BDSe) to 1,4-divinylbenzene (DVB) was carried out with various azo radical initiators [dimethyl 2,2′-azobisisobutyrate (DAIB), 1,1′-azobis(1-acetoxy-1-phenylethane) (AAPE), and AIBN] in toluene at 65 and 75°C under a nitrogen atmosphere. The polymerization proceded without an induction period, and pale-yellowish powder polymers were obtained in 89% yields for 75 h (DAIB), 89% yields for 24 h (AAPE), and 60% yields for 8 h (AIBN). The molecular weight (Mw) of the insoluble polymers in toluene was about 4000 (IBN) to 14,000 (DAIB or AAPE) by GPC. The polymer had an alternating structure of BDSe to DVB units by 1H-NMR, IR analyses, and selenium contents, but the polymer contained the diselenide linkage by Raman spectroscopy. By AIBN initiator, the yield of the polymers did not increase over 60% and higher molecular weight polymer was hardly obtained. According to the model addition reaction of benzeneselenol to styrene by AIBN, it was found that AIBN was consumed by the side reaction between dimethyl-N-(2-cyano-2-propyl)ketenimine derivedAppl 11 from AIBN and benzeneselenol to give the adduct C, MH+ 295 by DCI MS. On the other hand, DAIB and AAPE initiators, which do not form a ketenimine intermediate, gave the polymers of higher molecular weight in a higher yield. The polymer film exhibited high refractive index (n25D = 1.81) and a reversible phase transition between a transparency and an opaque by thermal mode. © 1994 John Wiley & Sons, Inc. 相似文献
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Ken‐Ichi Seno Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(17):5724-5733
Vinyl ether polymers with imidazolium or pyridinium salt pendants underwent sensitive lower critical solution temperature (LCST)‐type phase separation in organic media. Well‐defined poly(salts) were quantitatively prepared by reaction with corresponding imidazoles or pyridines and poly(2‐chloroethyl vinyl ether), which was synthesized by living cationic polymerization. For example, a solution of the homopolymer with butyl imidazolium salts exhibited a sharp and reversible transition in chloroform upon heating. Sensitive phase separation was also observed in nonpolar solvents, such as toluene, ethyl acetate, THF, containing a small amount of a good solvent, such as 1‐butanol (10–15 wt %). The dependency of the salt structures, molecular weight, and the concentration on this behavior was demonstrated. The cleavage of the hydrogen bond is a key factor in this phase separation, as indicated by DSC and 1H‐NMR measurements. On increasing the temperature, the interaction between the polymer pendant and the solvent became weaker, hence the pendant–pendant interaction was, in turn, induced through the counter anion. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5724–5733, 2008 相似文献