Microstructural characterization of acrylonitrile/pentyl acrylate copolymers by one and 2-D NMR spectroscopy

Abstract

ABSTRACT: Acrylonitrile/pentyl acrylate (A/P) copolymers of different monomer com-position were prepared by solution polymerization using benzoyl peroxide as initiator.Copolymer compositions were determined by elemental analysis and quantitative 13 C 1 H-NMR spectroscopy. The comonomer reactivity ratios, determined by both KelenTudos (KT) and nonlinear error in variables (EVM) methods are r A 5 0.75 and r p 5 0.45. 2-D heteronuclear correlation spectroscopy (HSQC) was used to simplify thecomplex 1 H spectra of A/P copolymers in terms of configurational and compositionalsequences. The microstructure was obtained in terms of the distribution of A- and P-centered triad sequences from 13 C 1 H-NMR spectra of the copolymers. The copolymer-ization mechanism was found to follow a first order Markov Model. © 1999 John Wiley S acrylonitrile; pentyl acrylate; copolymer; 2-D NMR;spectroscopy INTRODUCTION Homo and copolyacrylates are of great interest inmany industrial application because of the widerange of physical and chemical properties thatcan be covered by an appropriate choice of theside groups and copolymer systems. The differ-ences in the monomer sequence distributionwithin synthetic copolymers, result in differencesin the physical properties of the copolymers. Con-sequently, knowledge of the microstructure canbe crucial to understanding the macroscopic char-acteristics of polymers.