화학공학소재연구정보센터
Macromolecules, Vol.50, No.20, 8083-8096, 2017
Controlling Crystal Microstructure To Minimize Loss in Polymer Dielectrics
A model semicrystalline polymer, poly(ethylene naphthalate) (PEN), was used to examine how morphological factors inhibit chain segment relaxations that contribute to dielectric loss. This was achieved by manipulating the extent of crystallization and the crystalline microstructure through a combination of annealing and uniaxial drawing and investigating the effects on dielectric performance. Varying crystallization conditions influenced the dynamic Ts and extent of rigid amorphous fraction formation but had only a moderate effect on loss magnitude. Film orientation, however,, greatly reduced loss through strain-induced crystallization and the development of oriented-amorphous mesophasic regions. Postdrawing annealing conditions were capable of further refining the crystal Microstructure and, in turn; the dielectric properties. These findings demonstrate that the semicrystalline polymer morphology can hate a very significant influence on amorphous chain relaxations that contribute to dielectric loss, and understanding how processing conditions affect morphology is critical to the rational design of polymer dielectrics.