Synthesis and properties of new polyimides derived from 1,5‐bis(4‐aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

Abstract

SYNOPSISNovel aromatic polyimides containing bis (phenoxy ) naphthalene units were synthesized from 1,5-bis (4-aminophenoxy ) naphthalene ( APN ) and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide ( DMAc) to give poly (amic acid) s, followed by cyclodehydration to polyimides. The poly (amic acid) s had inherent viscosities between 0.72 and 1.94 dL/g, depending on the tetracarboxylic dianhydrides used. Excepting the polyimide IVb obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA ) , all other polyimides formed brown, flexible, and tough films by casting from the poly (amic acid) solutions. The polyimide synthesized from BPDA was characterized as semicrystalline, whereas the other polyimides showed amorphous patterns as shown by the x-ray diffraction studies. Tensile strength, initial moduli, and elongation at break of the APN-based polyimide films ranged from 105-135 MPa, 1.92-2.50 GPa, and 6-7%, respectively. These polyimides had glass transition temperatures between 228 and 317°C. Thermal analyses indicated that these polymers were fairly stable, and the 10% weight loss temperatures by TGA were recorded in the range of 543-574°C in nitrogen and 540466°C in air atmosphere, respectively. 0 1993 John Wiley & Sons, Inc.

Effect of Structure of Bridging Group on Curing and Properties of Bisphenol-A Based Novolac Epoxy Resins

“…[6][7][8] The introduction of naphthalene moiety is expected to greatly improve the thermal property and moisture resistance owing to its excellent rigidity, facile packing of molecules and significant degree of hydrophobicity. [9][10][11][12][13][14] Many studies reported that epoxy resin showed remarkably higher glass transition temperature (T g ), higher thermal stability, higher flexural modulus, better moisture resistance, lower coefficient of thermal expansion when stiff naphthalene was inserted or appended by chemical modification. [15][16][17][18] In order to design and develop more novel epoxy resins with higher thermal and mechanical properties to meet the application need, the deeply understanding the effect of the molecular structure of materials on curing behavior, chemical and physical properties of epoxy resin was increasingly more important, because it can predict the end product properties of the new materials and provide a guide for the development process and speed up the development cycle.…”

Novel organosoluable aromatic polyimides derived from unsymmetrical 1,3-bis(4-aminophenoxy)naphthalene and aromatic dianhydrides

“…Generally, the use of p-fluoronitrobenzene provided higher yield at the lower temperature. As to the past researches, [29][30][31][32][33][34] aromatic diamines based on bis(phenoxy)-naphthalene were prepared by using dihydroxynaphthalene and p-chloronitrobenzene to form dinitro compounds under alkaline environment and then followed by reduction to diamine under the presence of hydrazine. The use of p-chloronitrobenzene, however, required higher temperature and resulted in a lower yield.…”

“…[29][30][31][32][33][34] These bis(aminophenoxy)naphthalene have the different substitution positions (1,4), (1,5), (1,6), (1,7), (2,3), (2,6), and (2,7) in the naphthalene ring as shown in Figure 1. However, most of the phthalene-containing polyimides exhibited poor solubility due to the symmetrical structures [29][30][31][32] or less bulky pendant effect. 33,34 Among these polyimides, derived from bis(aminophenoxy)naphthalene-based diamines, the symmetrical 2,3-substituted polyimides showed better solubility 31 than the polyimides derived from unsymmetrical diamines.…”

“…[17][18][19][20] Generally, aromatic diamine with ether linkages and metaoriented phenylene groups led to an increase in polymer chain flexibility and solubility of polyimides, but has also lowered the effective upper use temperature of these polymers. 21 To improve the heat resistance of polyimides, one of the approach is to introduce thermal resistant groups into the polymer backbone, such as triazole, 22 carbazole, 23,24 pyridine, [25][26][27][28] and naphthalene [28][29][30][31][32][33][34] etc. Several polyimides containing naphthalene group have been developed by Yang et al.…”

Preparation of Novel Naphthalene Polyimide and Its Morphology

“…[1,2] Aromatic polyimides containing naphthalene moiety have been prepared to improve the heat resistance [3][4][5][6] and the linear coefficients of thermal expansion. [7,8] Although many naphthalene-containing polyimides have been synthesized so far, the self-condensable naphthalene-containing polyimide has not been synthesized because of the instability of monomers due to the facile reaction between the amino group and the anhydride group attached in the same molecule.…”