NMR STUDY OF THE MICROSTRUCTURE OF METHYL-N-HEXADECYL ITACONATE WITH STYRENE COPOLYMERS

Abstract

A series of copolymers of styrene with methyl-n-hexadecylitaconates using different compositions in the feed have been prepared in bulk via radical at 60ºC with AIBN as initiator. In most of the cases the copolymers were obtained in good yields and the increase of one of the monomers in the feed mixture raises its amount in the copolymer and in some cases the copolymer composition is close to the feed ratio. The copolymers molecular structure was characterized by FTIR and a detailed study of NMR spectroscopy  which included 1H, 13C and bidimentional experiments. The NMR studies indicate that  the  copolymers  have  a  mainly  random  distribution  of  the  monomeric  units  and  the  chemical  shifts  of  the  signals, especially the OCH3 and OCH2 are strongly influenced by the neighbor environment. 13C NMR chemical shifts were also analyzed  by  simulation  studies  using  ab  initio  Gauge-Independent  Atomic  Orbital  (GIAO)  calculations;  we  observed  a good correlation between the experimental and calculated values.