Polymer crosslinking by a bimolecular peroxide decomposition

Abstract

The present paper examines the possibility of the utilization of the bimolecular cumyl hydroperoxide redox decomposition, catalyzed by Co11 naphthenate for the polymer crosslinking. The study of the mechanism and the kinetics of this reaction was performed both in a model medium heptane and polymer or polymer solution. In the case of redox initiation, the value of the crosslinking efficiency was found to be about 0.4, and its decrease can be attributed mainly to the formation of ions and, partly, to recombination of peroxy radicals producing dialkyl peroxide. On the basis of data obtained concerning the efficiency and rate of the process, conclusions are made on its applicability, especially for the crosslinking below the melting point of a crystalline polymer, as is the case of the crosslinking of polyethylene films.

Crosslinking in metallocene ethylene-co-5,7-dimethylocta-1,6-diene copolymers initiated by electron-beam irradiation

“…Sterilization can be achieved through a variety of methodologies, the electronbeam irradiation being commonly utilized. As aforementioned, upon irradiation PE predominantly undergoes crosslinking in the amorphous regions or at the boundaries of crystallites [6]. The crosslinking takes place in the solid state and changes its morphological characteristics and, accordingly, its mechanical properties at ambient temperature.…”

“…Other procedures for initiation of polyolefin crosslinking are less frequently used or have only been investigated in the laboratory. These include high-frequency heating, initiation by thermal decomposition of azo-esters or ethers, UV irradiation, redox initiation and free radical initiated grafting of various moieties onto polyalkene chains which can react under various conditions leading to the formation of crosslinks often physical or physico-chemical in nature [6]. Several interesting modifications of peroxide initiated crosslinking were suggested.…”

Development of a Kinetic Model for Thermal Crosslinking of Rubbery Polymers

“…Direct attack to double bonds was considered to be negligible. [1,2,[4][5][6][7][8][9][10][11][12][13][14] Summary: A kinetic model for the thermal crosslinking of rubbery polymers is presented. The reaction mechanism used to develop the model includes thermal radical generation producing a polymeric radical and a primary radical, crosslinking from attack of a polymer radical to any inactive polymer molecule, bimolecular radical termination among chains of any degree of branching, and radical termination between a polymer radical and a primary radical from the thermal radical generation.…”