Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microsco...Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.展开更多
A stable polyradical, poly (2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), was synthesized,and its structure was determined by infrared, ultraviolet-visible, and ESR spectroscopy. Cyclic voltammograms ofthe P...A stable polyradical, poly (2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), was synthesized,and its structure was determined by infrared, ultraviolet-visible, and ESR spectroscopy. Cyclic voltammograms ofthe PTMA polyradical electrodes were obtained by using a three-electrode cell at a scan rate of 5 mV/s within a po-tential range of 3.2-4. 0 V. The results show that the shape of oxidation peak is very similar to that of reductionpeak, and oxidation peak current is equal to the corresponding reduction peak current, which suggest that PTMApossesses an excellent reversibility. The difference of the anodic peak potential (Ea,p =3.66 V, vs Li/Li+ ) and ca-thodic peak potential(Ec,p =3.58 V, vs Li/Li+ ) is estimated at 80 mV, which is extremely less than that of the oth-er organic positive materials in lithium second batteries such as organosulfide compounds, leading to a capability forhigh current capability in the charging and discharging process of the battery. The maximum discharge specific ca-pacity of PTMA is 78.4 mA @ h/g at the constant discharge current of 0.3 mA (0.2 C rate), the coulombic efficien-cy is about 95%, and the charging and discharging curves of the batteries have an obvious plateau at 3.65 V and3.56 V, respectively. The discharging specific capacity of the battery decreased is about 2% after 100 cycles. ThePTMA/Li button batteries exhibite an excellent stability.展开更多
文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射...文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射下,驱动丙烯酸甲酯(MA)和甲基丙烯酸甲酯(MMA)的P-ATRP反应且单体转化率达到99%。所得聚合物的结构明确,分子量可控,分子量分布(D-_(s)<1.18)窄。在太阳光照射条件下,TPP-CHCP依然具有优异的光催化活性,可高效制备嵌段共聚物。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
基金Project(21376271)supported by the National Natural Science Foundation of ChinaProject(2013)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,China+2 种基金Projects(CL12129,201310533008)supported by the Undergraduates Innovative Training Foundation of Central South University,ChinaProject(Z12060)supported by the Undergraduate Free Exploration Innovation Foundation of Central South University,ChinaProject(CSUZC2013008)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.
文摘A stable polyradical, poly (2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), was synthesized,and its structure was determined by infrared, ultraviolet-visible, and ESR spectroscopy. Cyclic voltammograms ofthe PTMA polyradical electrodes were obtained by using a three-electrode cell at a scan rate of 5 mV/s within a po-tential range of 3.2-4. 0 V. The results show that the shape of oxidation peak is very similar to that of reductionpeak, and oxidation peak current is equal to the corresponding reduction peak current, which suggest that PTMApossesses an excellent reversibility. The difference of the anodic peak potential (Ea,p =3.66 V, vs Li/Li+ ) and ca-thodic peak potential(Ec,p =3.58 V, vs Li/Li+ ) is estimated at 80 mV, which is extremely less than that of the oth-er organic positive materials in lithium second batteries such as organosulfide compounds, leading to a capability forhigh current capability in the charging and discharging process of the battery. The maximum discharge specific ca-pacity of PTMA is 78.4 mA @ h/g at the constant discharge current of 0.3 mA (0.2 C rate), the coulombic efficien-cy is about 95%, and the charging and discharging curves of the batteries have an obvious plateau at 3.65 V and3.56 V, respectively. The discharging specific capacity of the battery decreased is about 2% after 100 cycles. ThePTMA/Li button batteries exhibite an excellent stability.
文摘文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射下,驱动丙烯酸甲酯(MA)和甲基丙烯酸甲酯(MMA)的P-ATRP反应且单体转化率达到99%。所得聚合物的结构明确,分子量可控,分子量分布(D-_(s)<1.18)窄。在太阳光照射条件下,TPP-CHCP依然具有优异的光催化活性,可高效制备嵌段共聚物。
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。
