PREPARATION OF COPOLY(AMIDE-IMIDE)S VIA DIRECT POLYCONDENSATION

Preparation of various kinds of copoly(amide-imide) was carried out vi a direct polycondensation of trimellitic anhydride (TMA) with the corr esponding diamine mixture in the presence of an equimolar amount of th ionyl chloride (TC) as a condensing agent followed by thermal imidizat ion. The resulting copoly(amide-imide)s had inherent viscosities in th e range of 41 to 68 mL g(-1) and glass transition temperatures of 215 degrees C to 291 degrees C. These copoly(amide-imide)s had relatively good thermomechanical properties. That is, the initial decomposition t emperature (IDT) and tensile strength were 350 similar to 409 degrees C and 104 similar to 121 MPa, respectively. The melt viscosities of th e copoly(amide-imide)s measured at 345 degrees C under a frequency of 10(2) rad . s(-1) were in the range of 4.8 x 10(2) similar to 4.5 x 10 (3) Pa . s depending on comonomers, which are somewhat lower than that commerciallized PAI with 5.6 x 10(3) Pa . s.