Preparation and electrostatic dissipating properties of poly(oxyalkylene)imide grafted polypropylene copolymers

A series of poly(oxyalkylene)imide grafted polypropylenes were prepared from the reaction of maleated polypropylenes and various amines. The amines included crystalline and non-crystalline block poly(oxyethylene-oxypropylene)amines of average molecular weight (M-w) from 1000 to 8000. The reactions afforded comb-like copolymers consisting of a polypropylene backbone, poly(oxyalkylene) pendants and imide linkages. Their electrostatic dissipating properties, probed by measuring surface resistivity, were correlated with the chemical functionalities. Increasing the weight amount or the decreasing crystallinity of the poly(oxyethylene) pendants lowered the polymer surface resistivity significantly from 10(12) to 10(6.9) Omega/rectangle. In comparing the structural effect, the polypropylenes modified by low M-w of amines such as 2-aminoethanol, 1,2-ethylenediamine, N,N-dimethylaminopropylamine and their derivatives were also prepared. Factors including hydrophilicity, the presence of amine functionality or sodium ion in the structure also affected the copolymer electrostatic dissipating ability. A mechanism involving hydrogen bonding with moisture was proposed. (C) 1999 Elsevier Science Ltd. All rights reserved.