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 reaction (ZR), was applied to chemically synthesized poly( p -phenylenevinylene) (PPV) precursor films under various applied tensions ( σ ) and heater temperatures ( T h ). The changes in the structure, tensile, and viscoelastic properties of the resulting films were investigated. It was found that orientation function ( f ) of the ZD films increased with draw ratio (DR), regardless of the T h and σ values, and attained 0.862 (DR = 9). ZR was subsequently performed on the ZD film. The molecular orientation and PPV content were strongly affected by the T h: The film obtained at T h = 240 °C exhibited the highest f value, as high as 0.894, while a further increase in the T h resulted in a disorientation of molecular chains. On the other hand, the absorption ratio between 632 cm -1 (C−S stretch) and 965 cm -1 ( trans -vinylene C−H out-of-plane bend) ( A 632 /A 965 ) became almost zero at T h above 240 °C. The Young's modulus and tensile strength for the resulting 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 film was the value as high as 74.7 GPa and held 40 GPa even at 350 °C, which were considerably higher than those of the typical engineering plastics.