Polyimides Containing a Quinazolinone Moiety

Abstract

A novel heterocyclic diamine monomer, 2-(4-aminophenyl)-6-amino-4(3H)-quinazolinone was synthesized from readily available compounds in three steps in high yield. A series of novel polyimides containing the quinazolinone moiety were synthesized either by a one-step solution polymerization reaction or by a two-step procedure that included a ring-opening polyadddition to give poly(amic acid)s, followed by cyclodehydration to polyimides. In the one-step method in m-cresol or p-chlorophenol with isoquinoline catalyst, polyimides with inherent viscosities of 0.44−0.63 dL/g were obtained. Polyimides 4f and 4g from dianhydrides which have a flexible linkage, hexafluoroisopropylidene dianhydride (2f) and BPA dianhydride (2g), were soluble in hot m-cresol and could be cast into tough films from m-cresol solution. In the two-step method, poly(amic acid)s with inherent viscosity between 0.63 and 1.40 dL/g were obtained in DMAc at room temperature. The poly(amic acid)s were converted to the corresponding polyimide films by thermal cyclodehydration. The T g values of the polyimides ranged from 298 to 350 °C. Polyimide 4a from pyromellitic dianhydride (2a) did not show a clear transition in the DSC. Polyimides 4b from biphenyltetracarboxylic dianhydride (2b) and 4g were semicrystalline and showed clear endothermic peaks for T m at 465 and 356 °C, respectively. Degradation temperatures for 5% weight loss all occurred above 540 °C in nitrogen and above 537 °C in air. Young's moduli of thin films ranged from 2.34 to 4.89 GPa at room temperature and they maintained the high moduli to high temperatures. The monomer was successufuly copolymerized with 4,4‘-oxydianiline and 2g. With increasing incorporation of quinazolinone units, the copolymers had higher T g values, were more thermally stable, and had higher moduli.

Preparation and Characterization of 4,4′‐Bis(4‐aminophenoxy)diphenyl Sulfone Based Fluoropoly(ether‐imide)/Organo‐Modified Clay Nanocomposites

“…The thermo-mechanical properties of polyimides are directly related to the inter-and intramolecular chain conformation rotation flexibility beside the chemical structure. [4,56] They also depend on the previous heat history of the polymer samples. The results could be compared with increasing order of rigidity and stiffness in the polymer backbone provided by exfoliation of p-SED diamine-modified MMT clay as indicated by the increasing value of glass transition temperature.…”

“…An approach such as the incorporation of a flexible ether linkage and meta oriented phenylene rings into the polymer backbone has led to an increase in polymer chain flexibility and solubility of neat polyimides, but at the same time has lowered the effective upper use temperature of these polymers. [3][4][5][6][7][8][9] This drawback makes them rather unqualified for the ever increasing demand for higher upper use temperature materials for microelectronics applications. Similarly, incorporation of inorganic clay leads to high thermal stability, but at the expense of fracture toughness and mechanical properties.…”

1,2′-Bis(4-aminophenoxy)benzene based designed fluoro-poly(ether-imide)/MMT clay nanocomposites: Synthesis and properties for high performance applications

“…The thermo-mechanical properties of polyimides are directly related to the inter-and intra-molecular chain conformation rotational flexibility besides the chemical structure [32,33]. They also depend on the previous heat history of the polymer samples.…”

New soluble polyamides and polyimides containing polar functional groups: pendent pyrazole rings with amino and cyano groups

“…[4][5][6][7][8] For example, polyamides and polyimides containing trifluoromethyl groups show a high modulus, a low thermal expansion coefficient as well as good solubility, [9][10][11][12][13][14][15][16][17][18][19][20][21] and the incorporation of heterocyclic units into polyimide chains increases the glass transition temperature and thermal stability. [22][23][24][25][26][27] Also, soluble polyamides and polyimides containing crosslinkable pendent groups represent useful methods in many applications. [28,29] Introducing stable functional groups as substituents is interesting because they can be used to impart special functionalities to polymers and to improve their processability.…”