INFLUENCE OF THE SEQUENCE DISTRIBUTION ON THE CRYSTALLINE-STRUCTURE OF ETHYLENE-DIMETHYLAMINOETHYLMETHACRYLATE COPOLYMERS

The comonomer sequence distributions of a series of ethylene-dimethyla minoethylmethacrylate copolymers (EDAM) were measured by quantitative high-resolution C-13 n.m.r. spectroscopy. It was found that both the c rystallinity and the lamellar thickness of EDAM samples increase linea rly with the increase of the numerical average sequence length of ethy lene run. It was further demonstrated that only ethylene longer than a critical length can participate in crystallization. Such a critical l ength was found to be independent of the molecular weight and composit ion of EDAM samples under the same crystallization condition. (C) 1997 Elsevier Science Ltd.