3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA) was purchased from Thermo Fisher Scientific India Pvt.
The IEDAB/BTDA-PI was synthesized by thermal imidization method using synthesized diamine with BTDA. In a completely dried 25 mL three-necked round bottomed flask equipped with a stirring bar under nitrogen atmosphere, 3.52 g (0.01 mol) of IEDAB and 10 mL of DM Ac were taken and dissolved completely.
After the solution was stirred for 30 minutes, BTDA was added gradually in 2 h and then kept stirred for another 1 h to obtain poly(amide acid) (PAA).
Since the valence angle of C-O-C is 123[degrees], and the valence angle of C-CO-C is 127[degrees], BTDA is slightly more flexible than ODPA.
Recently, a novel PBA-a modified with dianhydride was successfully prepared by reacting bisphenol-A-aniline-based bifunctional benzoxazine resin (BA-a) with BTDA (14), (15).
In this study, we prepared a series of the high performance copolymers of PBA-a and aromatic carboxylic dianhydrides, i.e., PMDA, 3,3',4,4' biphenyltetracarboxylic dianhydride (s-BPDA), and BTDA. The effect of these aromatic carboxylic dianhydrides on thermomechanical properties of the obtained PBA-a:aromatic carboxylic dianhydride copolymers is investigated.
Replacement of BTDA dianhydride that can be considered as flexible groups by rigid dianhydride as BCDA and PDMA structure does not induce a systematic change on the [gamma] relaxation.
The BTDA diimine has a lower electron affinity than the PMDA moieties.
In this work 13C nuclear magnetic resonance, infrared spectroscopy, and investigation of the rheology of fused monomers were used to study the complex reactions between BTDA and di- and tetraacetyl derivatives of aromatic diamines during the formation of polyimide binders (DIM) and their curing.
BTDA was recrystallized from acetic anhydride, washed with ether, and vacuum-dried.
BTDA ([greater than or equal to]99% pure) was used as received from Allco, phthalic anhydride (PA) ([greater than]99% pure), and benzoyl chloride (BC) (99%) were used as received from Janssen.
Subsequently, 104.20 g (0.323 mole) of solid BTDA and 1.956 g (0.0132 mole, i.e.