Preparation of the blends of poly(amic acid) and PBO precursor and their properties

The themal properties, morphology, mechanical properties and gas permeability of the blends of poly (amic acid) (PAA) and poly (o-hydroxyamides) (PHAs) having pendant group was investigated. The 5% weight loss and major weight loss of the blends occurred in the ranges of 348 similar to 407 degrees C and 589 similar to 615 degrees C upon a heating process. After a thermcal annealing, the tensile strength and initial modulus of blends increased 3.7 similar to 52.9% and 34.4 similar to 70% from the value of pure PAA, respectively. Especially the tensile strength and modulus of the PAA/MP-PHA=9/1 showed the highest values (97.5 MPa and 2.67 GPa, respectively), which were 53 and 70% higher than those of pure PAA. The fine PHA domains were found to be uniformly dispersed. The interfacial adhesion between PAA and PHA was identified to be good. The gas permeabilities of PAA/M-PHA blend increased with M-PHA contents.