Studies on Polymerization of Vinyl Compounds Initiated by Metal Chelate II Kinetics of Polymerization of Methyl Methacrylate Initiated by Nickel Ethyl Acetoacetate in the Presence and the Absence of Aromatic Amines

Abstract

The kintetic studies of polymerization of methyl methacrylate initiated with nickel ethyl acetoacetate gave the following . Some aromatic amines such as aniline markedly accelerated the polymerization, while pyridine had no such effe:::t. The activation energy of initiation was 24.8 kcalfmot in the absence of aniline, and 8.8 kcal/mol in the presence of aniline. Both the kinetic data and the infrared spectra of the polymer indicated that the polymerization was radical in nature. The reaction order against monomer varied, as the temperature differed. The spectrophotometric investigation indicated formation of a complex between the chelate and the monomer, or amines. It also showed that the formation of a complex was not a factor which controlled the rate of initiation. A scheme of initiation mechanism was .presented on the basis of the above experimental evidence. InboducHonPolymerization of vinyl compounds initiated by metal chelates of l3-diketones has been studied by a few wcrker.P"? TJ1e function of the chelates has been considered a ttribu ta ble to the formation 145