Preparation and Properties of Rigid Polyimides from Dianhydrides Having Various Number of Phenylene Units and <i>p</i>-Phenylenediamine

Abstract

(DA-4), by a conventional two-step procedure that included ring-opening polymerization and subsequent thermal cyclic dehydration. The PI-PP-m (m = 0, 1, 2, 3) films were characterized by wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetry (TG), dynamic mechanical analysis (DMA), and stress-strain curves. The properties were compared on the basis of the number (m) of phenylene units. The glass transition temperatures (Tg) were observed at 270-280 o C as tan δ peak temperatures of DMA, and the values did not depend on m. The decrement of storage modulus at the T g was smaller with increasing m. The thermal properties of PI-PP-0 were compared with those previously reported for Upilex-S type polyimides prepared from p-phenylenediamine and DA-0.

Synthesis and Properties of Polyimides from Bis[4-(Aminophenoxy)phenyl] Ether and Aromatic Dianhydrides Having Various Numbers of Phenylene Units

“…PI-3e-m (m = 0-4) showed higher E' values in the rubbery plateau region above T g than those before annealing. The E' value for PI-3e-2 was higher than those for PI-3e-3 and PI-3e-4, in contrast to the previously reported polyimides [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] from dianhydrides having various numbers of phenylene units, for which the E' value was higher with increasing phenylene units (m).…”

“…3). The T g values for PI-3e-PMDA and PI-3e-0, PI-3e-1, PI-3e-2, PI-3e-3 and PI-3e-4 were 280 °C, 230 °C, 230 °C, 210 °C, 220 °C, and 210 °C, respectively (Table 1), which were slightly higher than those for PI-5e-PMDA and PI-5e-m (m = 0-4) [13], and the T g values were not dependent on m. The value for PI-3e-PMDA was the highest due to intermolecular charge transfer [19], similar to the case for previously reported polyimides from dianhydrides having various numbers of phenylene units [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…Remarkable elongations at about 330 °C for PI-3e-m (m = 2-4) were not observed, which reflected the DMA results. The elongations for PI-3e-m (m = 2-4) in the temperature range 50-450 °C were about 0.7%, and as short as those for the polyimides [16] from DA-m (m = 1-3) and pphenylenediamine, even though PI-3e-m (m = 2-4) had three flexible ether linkages in the repeating unit.…”

“…These were used to prepare aromatic polyimides containing pquarterphenyl [1], p-quinquephenyl [2] and psexiphenyl [3] with various aromatic diamines [4][5][6][7][8][9][10][11][12][13]. The properties were compared with those of polyimides from DA-0 and DA-1, and discussed on the basis of the number (m) of phenylene units [14][15][16]. The T g values were not dependent on m, but depended on the structure of the diamine as reported in the literature [17].…”

Preparation of Rigid Polyimides from Various Dianhydrides and 4,4’’’-Diaminoquaterphenyl and Comparison with Properties of Polyimides from 3,3’’’,4,4’’’-<i>p</i>-Quaterphenyltetracarboxylic Dianhydride

“…These were used to prepare aromatic polyimides PI-Ar-2 [1], PI-Ar-3 [2], and PI-Ar-4 [3] with commercially available aromatic diamines, and diamines that the authors had synthesized [4][5][6][7][8][9][10][11]. The properties were compared with those of polyimides from 3,3',4,4'-biphenyltetracarboxylic dianhydride DA-0 and 3,3'',4,4''-pterphenyltetracarboxylic dianhydride DA-1 and discussed on the basis of the number m of phenylene units [12][13][14]. The T g values depended on the connecting group and the structure of the diamine moiety [15], but did not depend on m, whereas there was a smaller decrease in the modulus at T g with increasing m. Here, we report the synthesis and characterization of novel aromatic polyimides PI-DAQ-Ar from 4,4'''diaminoquaterphenyl DAQ having four phenylene units.…”