Self-assembly behaviour of amphiphilic diblock copolymer in selective solvents studied by synchrotron small-angle x-ray scattering

The aggregation behaviour of styrene-vinyl benzoic acid (PSm-b-PVBAn) amphiphilic diblock copolymers in selective solvents with different m and n was investigated by synchrotron small-angle x-ray scattering (SAXS). We have carried out a detailed analysis of scattering intensity, dimension, shape and microstructure of the diblock copolymers of narrow distribution in water, methanol, ethanol and isopropanol selective solvents, respectively. We have found that the aggregation behaviour of the copolymer depends on the nature of the solvent and the micelle forms fiat disc objects with the ratio of radius ω=0.4. The average radius gyration Rg of the copolymer decreases as solvents change from isopropanol to ethanol and to methanol, and increases with increasing pH in aqueous solution, but decreases with the addition of COCl2 in ethanol solvent. The scattering intensity of diblock copolymer micelle follows I(h) ∝ h^-α in different selective solutions, suggesting that the PSm-b-PVBAn coils have self-similar structure behaviour or a fractal structure in the selective solvents. All of these revealed that the aggregation behaviour of the diblock copolymer changes dramatically with experimental condition in the selective solvent. The increase of mass fractal dimension (Dm) from 2.12 to 2.47 indicates that the copolymer chain changes from a swollen coil to a rather compact disc in the course of changing solvents, decreasing surface fractal dimension (Ds) from 2.98 to 2.58 indicates that the copolymer micelle change from a rather rough surface to a smooth form in the course of increasing pH in aqueous solutions, and increasing Dm and Ds from 2.29 to 2.35 and 2.70 to 2.90, respectively, indicates the shrinkage of copolymer micelle to a rather compact and rough disc form by adding COCl2 in ethanol solvents.     

SYNTHESIS OF MACROPOROUS COPOLYMER OF VCA AND DVB

The reactivity ratios of vinyl acetate(VAc) and divinyl benzene (DVB) were calculated from the Q and e values.The possibility of the copolymerization of these two monomers was predicted and the copolymerization was carried out by suspension polymerization technique in the presence of pore producing agent (toluene and gasoine).The relative ratio of acetoxy group and benzene ring in the copolymer were monitored by IR measurement during the polymerization.The variation of pore properties,such as spectific surface area,porosity and average pore diameter,with polymerization time were determined.The copolymers at various polymerization time were alcoholyzed and thus the variation of the hydroxyl group content with polymerization time was studied.     

配合物的生成热和配体的质子化热之间的直线焓关系——Ⅶ.Ni(Ⅱ)-2,2′-联吡啶-N-(间位取代苯基)氨基乙酸三元体系

有关Ni(Ⅱ)-N-(间位取代苯基)氨基乙酸二元体系的直线焓和直线熵关系,前文已有报道,本文报告Ni(Ⅱ)-2,2′-联吡啶-N-(间位取代苯基)氨基乙酸(Ni(Ⅱ)-biPy-m-RPhG:R=CH_3,H,CH_3O,Cl)三元体系的生成热研究,发现在此三元体系中亦存在良好的直线焓和直线熵关系。     

立体定向合成粘虫性信息素

粘虫是一种多食性害虫,分布极广。它的危害对象包括麦类、水稻、玉米等十多种粮食和经济作物。1979年Takahashi等首先确定粘虫雄蛾(Mythimna Separata male)的性信息素,这是由8:1比例混合的(Z)-11-十六碳烯-1-醇乙酸酯3和(Z)-11-十六碳烯-1-醇4组     

KMnO4引发魔芋粉-丙烯腈的接枝共聚反应

以KMnO4为引发剂进行魔芋粉与丙烯腈的接枝共聚反应。研究了魔芋粉预氧化时间、引发剂浓度、单体浓度、酸度、反应时间、反应温度和反应物加料方式等聚合条件对接枝效率的影响，并对接枝机理作了探讨。     

亚麻等麻类纤维与乙烯基类单体接枝共聚反应的研究进展

近年来,乙烯基类单体与亚麻、大麻、苧麻等麻类纤维的接枝共聚反应已得到关注。本文着重总结接枝的引发方法,包括:1.辐射引发接枝;2.光引发接枝;3.Ce(Ⅳ)离子引发接枝;4.锰盐引发接枝;5.V(Ⅴ)离子引发接枝;6.Fenton's 试剂(Fe~(2+)-H_2O_2)引发接枝;7.过硫酸盐氧化还原引发体系接枝。上述各类引发体系及接枝纤维的结构与性能表征均在本文中作了述评。