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Dong Xie Xian-hong Wang Xiao-jiang Zhao Fo-song Wang 《高分子科学》2005,(6):671-674
Rare-earth ternary catalysts Y(CCl3COO)3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide (PO), where dialkylzincs (ZnR2) were diethylzinc, di(n-propyl)zinc, di(n-butyl)zinc, di(i-propyl)zinc, di(i-butyl)zinc, di(s-butyl)zinc,respectively. The Y(CCl3COO)3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y(CCl3COO)3:ZnR2:glycerin = 1:20:10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence: Y(CCl3COO)3-ZnEt2-glycerin 〉 Y(CCl3COO)3-Zn(n- Pr)2-glycerin〉Y(CCl3COO)3-Zn(n-Bu)2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end. 相似文献
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Wen-xun Guo Zong-li Shi Kui Liang Yan-li Liu Xian-hong Chen Wei Li 《Polymer Degradation and Stability》2007,92(3):407-413
New unsaturated polyesters of poly(fumaric acid-glycol-sebacic acid) copolymers and poly(maleic anhydride-glycol-sebacic acid) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: sebacic anhydride, fumaric acid or maleic anhydride and glycol. Methyl-methacrylate (MMA) was used as crosslinker and dimer acid was used as thinner.In vitro studies showed that those copolymers are degradable in phosphate buffer at 37 °C and poly(fumaric acid-glycol-sebacic acid) has proper drug release rate as drug carriers. The biocompatibility of poly(fumaric acid-glycol-sebacic acid) copolymers under mice skin was also evaluated; macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. The injected poly(fumaric acid-glycol-sebacic acid) [molar ratio Mfumaric acid:Mglycol:Msebacic acid = 1.75:2.20:0.25] containing 5% adriamycin hydrochloride (ADM) in the mice bearing Sarcoma-180 tumor exhibited a good antitumor efficacy. The volume doubling time (VDT) (18 ± 2.5 days) of the tumor growth by this treatment was longer than that (7 ± 0.9 days) by the subcutaneous injection of ADM. 相似文献
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提出了吹扫捕集-气相色谱-质谱法测定水中硝基苯、三氯苯、硝基氯苯、四氯苯、六氯苯等10种半挥发性有机物含量的方法。选择吹扫温度和吹扫时间分别为60℃和8min。在气相色谱分离中用DB-5MS毛细管色谱柱为固定相,在质谱分析中采用全扫描监测模式,内标法定量。10种半挥发性有机物的线性范围均为0.5~20μg·L-1,检出限(3S/N)在0.005 9~0.073μg·L-1之间。以地表水、生活污水和工业废水为基体做加标回收试验,测得10种半挥发性有机物的回收率在80.4%~105%之间,测定值的相对标准偏差(n=6)在2.4%~16%之间。 相似文献
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Ten novel N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles were synthesized by Claisen condensation of the aryl methyl ketones with ethyl nicotinate, the cyclization with hydrazine hydrate and the N-acylation with acyl chloride in turn. The structures of all the compounds synthesized were confirmed by means of Fourier transform infrared(FTIR), 1H NMR, mass spectroscopy and elemental analysis. The biological activities of the title compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles exhibited a certain degree of antibacterial and antifungal activities. Comparatively, compounds 3c and 3d exhibited much significant antibacterial and antifungal activities than the other pyrazole derivatives. 相似文献
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N-溴代丁二酰亚胺与天然橡胶(NR)反应合成了大分子引发剂——溴代天然橡胶[NR-Br(1)].通过原子转移自由基聚合(ATRP),以CuBr/PMDTA为催化体系,1引发甲基丙烯酸甲酯(MMA)接枝共聚制得新型天然橡胶-g-聚甲基丙烯酸甲酯[NR-g-PMMA(2)],其结构经1H NMR和IR表征.初步聚合反应动力学研究结果表明,NBS与NR在高温下反应容易伴随双键加成和环化反应,于室温反应所得1具有较高的引发活性;接枝聚合符合一级动力学反应,即2的分子量随MMA单体转化率的提高而增加. 相似文献