This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ ...This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ and above 0℃. The amount of catalyst used was studied. When zinc iodide catalyst used is more than 10mol% relative to monomer, the rate of polymerization is proportional to the concentration of monomer, whereas zinc iodide catalyst used is less than 10 mol% of the monomer, the rate of polymerization is independent of the monomer concentration.In the GTP of EA an induction period was observed when the zinc iodide contents are less than l0mol%. If the reaction temperature is over 0℃, living species become unstable and diminish, leading to incomplete monomer conversion. The reaction curves equations are obtained. The polymers have narrow molecular weight distributions which are not changed as decreasing zinc iodide contents. The polydispersity is about 1.2.展开更多
It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA a...It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA and PMA with controlled molecular weight and low polydispersity were obtained by using non-acetal initiators in the presence of bibenzoate,bifluo ide or Hgl_2,The living nature of polymerization is shown by the correspondence of theoretical and observed molecular weight and the preparation of A-B-A type triblock copolymer with methacrylate and acrylate segments can be prepared.展开更多
INTRODUCTION Group transfer polymerization (GTP) is a method for controlling the structure of acrylic polymers in which reactive chain ends are covalentiy bound to a trimethylsilyl group. In the presence of a catalyst...INTRODUCTION Group transfer polymerization (GTP) is a method for controlling the structure of acrylic polymers in which reactive chain ends are covalentiy bound to a trimethylsilyl group. In the presence of a catalyst, monomer inserts into these chain ends between the silyl group and the last monomer unit. The process is illustrated by equation (1) for methyl methacrylate. GTP is a living polymerization, i. e., there is little or no chain termination and no chain transfer. A significant advantage of GTP is that it展开更多
以玉米芯为原料,利用原子转移自由基聚合(atomic transfer radical polymerization,ATRP)技术在其表面引发丙烯酸甲酯发生聚合反应,再利用NaOH将嫁接在玉米芯表面的聚丙烯酸甲酯水解成聚丙烯酸钠,得到羧基化玉米芯吸附材料(C-C-A)。通...以玉米芯为原料,利用原子转移自由基聚合(atomic transfer radical polymerization,ATRP)技术在其表面引发丙烯酸甲酯发生聚合反应,再利用NaOH将嫁接在玉米芯表面的聚丙烯酸甲酯水解成聚丙烯酸钠,得到羧基化玉米芯吸附材料(C-C-A)。通过单因素试验和正交试验优化得到C-C-A最佳制备条件,同时采用FTIR、SEM-EDS和XPS对C-C-A进行表征,结果表明其表面凹凸不平,存在大量羧基。C-C-A对Pb^(2+)、Cd^(2+)、Cu^(2+)和Ni^(2+)的去除率均可达到98%以上,说明其可以有效去除重金属离子。C-C-A吸附重金属离子的过程既符合Pseudo-second-order动力学模型,又符合Langmuir等温线模型,属于单分子层化学吸附,且吸附较快。展开更多
基团转移聚合(Group Transfer Polymerization,GTP)作为一种新的加聚方式,由于具有室温下使极性单体快速聚合;得到预期分子量和窄分子量分布的聚合物;可进行活性聚合,制备嵌段共聚物,对合成丙烯酸酯类橡胶或热塑性弹性体极为有利;可合...基团转移聚合(Group Transfer Polymerization,GTP)作为一种新的加聚方式,由于具有室温下使极性单体快速聚合;得到预期分子量和窄分子量分布的聚合物;可进行活性聚合,制备嵌段共聚物,对合成丙烯酸酯类橡胶或热塑性弹性体极为有利;可合成带有功能性端基和遥爪的聚合物等优点,近几年来发展迅速。到目前为止。展开更多
文摘This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ and above 0℃. The amount of catalyst used was studied. When zinc iodide catalyst used is more than 10mol% relative to monomer, the rate of polymerization is proportional to the concentration of monomer, whereas zinc iodide catalyst used is less than 10 mol% of the monomer, the rate of polymerization is independent of the monomer concentration.In the GTP of EA an induction period was observed when the zinc iodide contents are less than l0mol%. If the reaction temperature is over 0℃, living species become unstable and diminish, leading to incomplete monomer conversion. The reaction curves equations are obtained. The polymers have narrow molecular weight distributions which are not changed as decreasing zinc iodide contents. The polydispersity is about 1.2.
文摘It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA and PMA with controlled molecular weight and low polydispersity were obtained by using non-acetal initiators in the presence of bibenzoate,bifluo ide or Hgl_2,The living nature of polymerization is shown by the correspondence of theoretical and observed molecular weight and the preparation of A-B-A type triblock copolymer with methacrylate and acrylate segments can be prepared.
文摘INTRODUCTION Group transfer polymerization (GTP) is a method for controlling the structure of acrylic polymers in which reactive chain ends are covalentiy bound to a trimethylsilyl group. In the presence of a catalyst, monomer inserts into these chain ends between the silyl group and the last monomer unit. The process is illustrated by equation (1) for methyl methacrylate. GTP is a living polymerization, i. e., there is little or no chain termination and no chain transfer. A significant advantage of GTP is that it
文摘以玉米芯为原料,利用原子转移自由基聚合(atomic transfer radical polymerization,ATRP)技术在其表面引发丙烯酸甲酯发生聚合反应,再利用NaOH将嫁接在玉米芯表面的聚丙烯酸甲酯水解成聚丙烯酸钠,得到羧基化玉米芯吸附材料(C-C-A)。通过单因素试验和正交试验优化得到C-C-A最佳制备条件,同时采用FTIR、SEM-EDS和XPS对C-C-A进行表征,结果表明其表面凹凸不平,存在大量羧基。C-C-A对Pb^(2+)、Cd^(2+)、Cu^(2+)和Ni^(2+)的去除率均可达到98%以上,说明其可以有效去除重金属离子。C-C-A吸附重金属离子的过程既符合Pseudo-second-order动力学模型,又符合Langmuir等温线模型,属于单分子层化学吸附,且吸附较快。
文摘基团转移聚合(Group Transfer Polymerization,GTP)作为一种新的加聚方式,由于具有室温下使极性单体快速聚合;得到预期分子量和窄分子量分布的聚合物;可进行活性聚合,制备嵌段共聚物,对合成丙烯酸酯类橡胶或热塑性弹性体极为有利;可合成带有功能性端基和遥爪的聚合物等优点,近几年来发展迅速。到目前为止。
