Dielectric relaxation of monoesters based poly(styrene-co-maleic anhydride) copolymer

摘要

A series of alkyl-grafted copolymers based on styrene-maleic anhydride (SMA) copolymers were synthesized by esterification of SMA with several long chain normal aliphatic alcohols. The prepared copolymers were characterized by FT-IR and H-1 NMR and DSC. The dielectric behavior of these copolymers was investigated in the frequency 20-10(5) Hz and temperature -40 to 180 degrees C ranges. Two relaxation processes were observed, alpha, and beta-relaxation. The former is associated with the glass-rubber transition and is characterized by the Vogel-Fulcher-Tammann temperature dependence and the latter relaxation is related to the local motion of the ester side groups attached to the polymer backbone. The apparent activation energy for the beta-relaxation was found to depend significantly on the alkyl chain length. The dielectric analysis of the beta-relaxation process detected is discussed.