Properties of fluoro-containing aromatic polyamide film and its high temperature zone drawing

Abstract

In order to drive in fluoro-containing aromatic polyamide 4,4'-diamino biphenyl (DABP), 2,2'-dimethyl benzidine dihydrochloride (DBHC), and 2,2'-bis(trifluoromethyl) benzidine(PFMB), respectively, were synthesized as diamine components, and 4,4'-(hexafluoroisopropylidene)bis(benzoyl chloride) (HPBC) was synthesized as diacid chloride. Aromatic polyamides having fluoro moieties in the main chain were prepared by polycondensation reaction of these monomers, and isotropic films were made from them. The structure of these monomers and polymers were determined by FT-IR, H-1-NMR and elemental analyses. Their thermal properties were characterized by DSC and TGA. The polymers had inherent viscosities of 1.2 similar to 1.7 dL/g, and T-d was over 450 degrees C. In order to orient molecular chain of films prepared, high temperature zone drawing method was applied at 350 degrees C. The draw ratio up to 4.2 was achieved by drawing PFMB/HPBC Film with drawing stress of 100 MPa., Birefringence of the drawn film showed the value of 0.019 similar to 0.036. Tensile properties of the film increased with an increase in the draw ratio. Also, the maximum tensile strength and modulus of film up to 0.35 GPa and 8 GPa, respectively, were achieved by drawing PFMB/HPBC film. Crystal orientation index of the drawing film was below 0.9 as determined by wide angle X-ray diffraction analysis. On the other hand, maximum birefringence of over 0.035 was observed. From these facts, it was identified that the effect of amorphous orientation is more predominant than that of crystal orientation.