Mechanical properties and structure of poly(p-phenylenevinylene) films prepared by the zone-reaction method

The "zone-reaction method", consisting of zone drawing (ZD) and zone reacti on (ZR), was applied to chemically synthesized poly(p-phenylenevinylene) (P PV) precursor films under various applied tensions (sigma) and heater tempe ratures (Th) The changes in the structure, tensile, and viscoelastic proper ties of the resulting films were investigated. It was found that orientatio n function (f) of the ZD films increased with draw ratio (DR), regardless o f the T-h and sigma values, and attained 0.862 (DR = 9). ZR was subsequentl y performed on the ZD film. The molecular orientation and PPV content were strongly affected by the Th: The film obtained at T-h = 240 degrees C exhib ited the highest f value, as high as 0.894, while a further increase in the Th resulted in a disorientation of molecular chains. On the other hand, th e absorption ratio between 632 cm(-1) (C-S stretch) and 965 cm(-1) (trans-v inylene C-H out-of-plane bend) (A(632)/A(965)) became almost zero at T-h ab ove 240 degrees C. The Young's modulus and tensile strength for the resulti ng ZR film respectively increased to 69.4 and 1.3 GPa from 2.1 and 0.04 GPa of as-cast original film. The dynamic storage modulus for the ZR him was t he value as high as 74.7 GPa and held 40 GPa even at 350 degrees C, which w ere considerably higher than those of the typical engineering plastics.