采用限制几何构型催化剂2-四甲基环戊二烯基-4,6-二叔丁基苯氧基二氯化钛/助剂Al（i-Bu）3-[Ph3C]＋[B（C6F5）4]-催化体系催化乙烯与1-己烯共聚,采用13 C NMR、GPC和DSC表征了共聚物的结构和性质,探讨了反应温度（40~80℃）和共聚单体...采用限制几何构型催化剂2-四甲基环戊二烯基-4,6-二叔丁基苯氧基二氯化钛/助剂Al（i-Bu）3-[Ph3C]＋[B（C6F5）4]-催化体系催化乙烯与1-己烯共聚,采用13 C NMR、GPC和DSC表征了共聚物的结构和性质,探讨了反应温度（40~80℃）和共聚单体初始浓度（0.1~0.4mol/L）对该体系催化活性和共聚物性质及其微观结构的影响,并采用一级Markovian模型和Bernoullion模型对共聚物序列分布进行概率统计分析。结果表明,在实验条件下,得到的共聚物是无规结构的聚合物,具有较低的相对分子质量（（0.87~6.73）×10^4）、适中的共聚单体质量分数（8.8%~28.8%）和熔点（107.5~121.0℃）。该共聚物的链增长符合一级Markovian模型的链增长机理,1-己烯共聚单体配位或插入到{共聚物链-1-己烯-1-己烯-催化剂}序列（[HH]）要比配位或插入到{共聚物链-乙烯-1-己烯-催化剂}序列（[EH]）更容易（概率参数PHH〉PEH）,乙烯共聚单体配位或插入到{共聚物链-乙烯-乙烯-催化剂}序列（[EE]）要比配位或插入到{共聚物链-1-己烯-乙烯-催化剂}序列（[HE]）更容易（概率参数PEE〉PHE）。PEH〈0.5和PHE〉0.5表现出了随机分布的乙烯基共聚物的特征。展开更多
Ring-opening metathesis polymerization of norbornene catalyzed by Grubbs catalyst [(PCy3)2·(Cl)2Ru=CHPh] was carried out. The results of 1H NMR demonstrated that the polymerization of the norbornene monomer proce...Ring-opening metathesis polymerization of norbornene catalyzed by Grubbs catalyst [(PCy3)2·(Cl)2Ru=CHPh] was carried out. The results of 1H NMR demonstrated that the polymerization of the norbornene monomer proceeded by the ROMP mechanism. The molecular weight and molecular weight distribution of this reaction can be controlled by changing the stirring time of catalyst, choosing different solvents and the adding of PPh3 during the polymerization. The results show that stirring the catalyst for 15 min, using more polar solvent and adding 2 equiv of PPh3 can optimize the conditions of this reaction. The polydispersity indices(PDIs) of the poly(norbornene) were nearly monodisperse(PDIs about 1.18).展开更多
采用水热合成技术将表面修饰有羧基的纳米 Cd Te微粒与表面活性剂和硅源进行自组装 ,得到了一种与氧化硅复合的稳定的 Cd Te发光材料 .通过一系列表征手段 (如 TG-DTA,EDX,TEM,荧光光谱和 N2吸附 )证实了 Cd Te微粒复合在氧化硅中 .进...采用水热合成技术将表面修饰有羧基的纳米 Cd Te微粒与表面活性剂和硅源进行自组装 ,得到了一种与氧化硅复合的稳定的 Cd Te发光材料 .通过一系列表征手段 (如 TG-DTA,EDX,TEM,荧光光谱和 N2吸附 )证实了 Cd Te微粒复合在氧化硅中 .进一步通过烧结的方法除去表面活性剂 ,用稀酸除去金属氧化物 。展开更多
文摘采用限制几何构型催化剂2-四甲基环戊二烯基-4,6-二叔丁基苯氧基二氯化钛/助剂Al（i-Bu）3-[Ph3C]＋[B（C6F5）4]-催化体系催化乙烯与1-己烯共聚,采用13 C NMR、GPC和DSC表征了共聚物的结构和性质,探讨了反应温度（40~80℃）和共聚单体初始浓度（0.1~0.4mol/L）对该体系催化活性和共聚物性质及其微观结构的影响,并采用一级Markovian模型和Bernoullion模型对共聚物序列分布进行概率统计分析。结果表明,在实验条件下,得到的共聚物是无规结构的聚合物,具有较低的相对分子质量（（0.87~6.73）×10^4）、适中的共聚单体质量分数（8.8%~28.8%）和熔点（107.5~121.0℃）。该共聚物的链增长符合一级Markovian模型的链增长机理,1-己烯共聚单体配位或插入到{共聚物链-1-己烯-1-己烯-催化剂}序列（[HH]）要比配位或插入到{共聚物链-乙烯-1-己烯-催化剂}序列（[EH]）更容易（概率参数PHH〉PEH）,乙烯共聚单体配位或插入到{共聚物链-乙烯-乙烯-催化剂}序列（[EE]）要比配位或插入到{共聚物链-1-己烯-乙烯-催化剂}序列（[HE]）更容易（概率参数PEE〉PHE）。PEH〈0.5和PHE〉0.5表现出了随机分布的乙烯基共聚物的特征。
文摘Ring-opening metathesis polymerization of norbornene catalyzed by Grubbs catalyst [(PCy3)2·(Cl)2Ru=CHPh] was carried out. The results of 1H NMR demonstrated that the polymerization of the norbornene monomer proceeded by the ROMP mechanism. The molecular weight and molecular weight distribution of this reaction can be controlled by changing the stirring time of catalyst, choosing different solvents and the adding of PPh3 during the polymerization. The results show that stirring the catalyst for 15 min, using more polar solvent and adding 2 equiv of PPh3 can optimize the conditions of this reaction. The polydispersity indices(PDIs) of the poly(norbornene) were nearly monodisperse(PDIs about 1.18).
基金Supported by the National Natural Science Foundation of China (20171028,20325105,2057104)the Shandong Postdoc-tor Innovative Project (200703055)The"Chunlei"Project in SDUST(06540040701)~~
