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本文采用 DSC技术,系统地研究了具有不同形态结构的聚苯乙烯-聚异戊二烯二嵌段共聚物的玻璃化转变及其微相分离行为。研究表明:PI相的玻璃化转变温度T_(g1)高于纯PI的T_g,并随PI嵌段子量的降低而略有升高;由PS组成基体(PS含量高)的嵌段共聚物的T_(g1)低于由PI组成基体(PS含量低)的嵌段共聚物的T_(g1),PS相的玻璃化转变温度T_(g2)低于纯PS的T_g,并随 PS嵌段分子量的降低而显著下降;由PS组成基体(PS含量高)的嵌段共聚物的T_(g2)高于白PI组成基体(PS含量低)的嵌段共聚物的T_(g2)。以上实验事实均可由在分相界面区内以化学链相连的PS与PI链段间的相互作用及其对PS与PI链段运动的影响予以解释。 相似文献
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采用体积排斥色谱法 (SEC) /示差折光指数 (RI) /直角激光光散射 (RALLS) /示差粘度 (DV )三检测联用技术 ,在THF为溶剂、2 5℃的条件下表征了聚 (α 甲基苯乙烯 异戊二烯 ) (PαMS PI)二嵌段共聚物 ;计算得到了PαMS PI分子的无扰尺寸A为 0 .0 778nm·mol1/ 2 ·g-1/ 2 ;根据PαMS PI与PS分子的无扰尺寸A ,比较了两者在 2 5℃、THF溶剂体系中的链柔性程度 ,证明在此体系中PαMS PI与PS的链柔性程度相当 ;验证了PαMS PI符合普适标定规律 相似文献
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用解偏振光强法和差示扫描量热法(DSC)分别研究了聚甲醛和聚甲醛助剂P的等温结晶动力学和非等温结晶动力学。探讨了助剂P对聚甲醛的结晶成核作用。 相似文献
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The normal growth rates and slopes of the dominant growth spirals on a crystal face were measured using a novel application of interferometry and atomic force microscopy. The dislocations responsible for the spirals were also observed directly. In this way it was shown that the velocities of similar steps on growth spirals of different activity, growing simultaneously on the same crystal face, were the same, and hence independent of the growth spirals to which they belonged. With this information the relative activities of the spirals were quantified and discussed in terms of hollow dislocation cores and the back-stress effect. 相似文献
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Deng S Sriwichai S Taranekar P Krueger G Mays JW Advincula RC 《Chemical communications (Cambridge, England)》2011,47(31):8805-8807
A series of thiophene dendrons and dendrimers with peripheral functional groups were designed and synthesized. Two methodologies using thiophene dendrons and dendrons as synthetic building blocks, namely, (1) periphery functionalization; (2) a combination of focal and periphery functionalization have been demonstrated. 相似文献
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本文采用透射电镜(TEM)法,系统地研究了具有不同组成,不同分子量和不同形态结构的聚(苯乙烯-异戊二烯)二嵌段共聚物,并由TEM照片直接测量具有栓状,层状和有规双连续双金钢石(OBDD)结构的PS-PI二嵌共聚物的微区尺寸,讨论了其与分子量的关系。实验证明嵌段共聚物微相分离有规结构的微区尺寸大小与分子量呈2/3的关系。 相似文献
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Mays也采用Bohdaneky的方法测定了一系列不同分子量级分的(cyanoethyl)(hydroxy-propyl) cellulose (CEHPC)的特性粘数。 相似文献
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Zhang H Hong K Jablonsky M Mays JW 《Chemical communications (Cambridge, England)》2003,(12):1356-1357
Use of a room temperature ionic liquid as the medium for conventional free radical copolymerization of styrene and methyl methacrylate resulted in reactivity ratios that were significantly different from those obtained in conventional organic solvents or in bulk, demonstrating that polymerization in this alternative medium offers potential to create copolymers having new monomer sequences. 相似文献