Artículos de revistas
Cycloalkyl-substituted salicylaldimine-nickel(II) complexes as mediators in controlled radical polymerization of vinyl acetate
Fecha
2019-09-09Registro en:
Journal Of Macromolecular Science Part A-pure And Applied Chemistry. Philadelphia: Taylor & Francis Inc, 9 p., 2019.
1060-1325
10.1080/10601325.2019.1661781
WOS:000485356700001
Autor
Univ Estadual Piaui
Universidade Estadual Paulista (Unesp)
Universidade Federal de Uberlândia (UFU)
Univ Fed Triangulo Mineiro
Universidade de São Paulo (USP)
Institución
Resumen
Nickel(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl (cpen), cyclohexyl (chex), and cycloheptyl (chep)) were synthesized: [Ni-II(L-cpen)(2)] (1), [Ni-II(L-chex)(2)] (2), and [Ni-II(L-chep)(2)] (3). The Schiff base-Ni-II complexes 1-3 were characterized by FTIR, UV-Vis, elemental analysis, and computational methods. Electrodeposited films of complexes 1-3 were obtained by potential cycling CH2Cl2 on platinum electrode, and their electrochemical behavior were characterized by cyclic voltammetry. The polymerization of vinyl acetate (VAc) initiated by azobisisobutyronitrile (AIBN) at 55 degrees C were conducted according to an organometallic-mediated radical polymerization (OMRP) mechanism. The best conversions were obtained using a ratio of [VAc]/[AIBN]/[Ni] = 542/3.25/1, reaching 50, 69 and 85% in 12 h for 1, 2 and 3, respectively. The kinetic of polymerization mediated by complex 1 exhibited a linear dependence of ln([VAc](0)/[VAc]) versus time, supporting a constant radical concentration; while for the complexes 2 and 3, the radical concentration was constant for a short period of time. The increase of molecular weights with the conversion coupled with low polydispersities indicate a certain level of control of the polymerization when using the complexes [Ni-II(L (R))(2)] as controlling agents.