Chlorocarboxylation of polyethylene. IV. Radical scavenging action of maleic anhydride

Abstract

Radical scavenging action of maleic anhydride (MA) is observed during chlorocarboxylation of polyethylene (PE) (CCPE). Reduction in the rate of chlorination is observed in the presence of MA in the CCPE process as compared to the rate of chlorination of PE (CPE) alone. Reduction in the rate of chlorination is due to the competitive nature of CCPE process and the radical scavenging action of MA. Radical scavenging action arises as a result of the formation of MA excimers of very short half life and their interactions with solvent. Other reactions responsible for scavenging action may also exist and are discussed. The kinetics of the scavenging process is studied by considering number of sites (N^-_0Cl), (N^-_Cl + N^-_MA) occupied during CPE and CCPE processes, respectively. The temperature dependence of the apparent rate constant k_SCV is investigated and reveals that activation energy and pre-exponential factor are of the order of 10.3 kcal/mol and 9.1 s^-1, respectively.