HighT_gand Thermo‐Oxidatively Stable Thermosetting Polyimides Derived from a Carborane‐Containing Diamine

Abstract

To provide high-temperature polyimide matrix resins, novel carborane-containing thermosetting polyimides are presented. First, the low-viscosity carborane-containing imide oligomers are synthesized using newly designed 1-(3-amino-4-tolyl)-2-(4-aminophenyl)-o-carborane and aromatic dianhydride as monomers, 4-phenylethynyl phthalic anhydride as the end-capping reagent. Followed by thermal curing, the resulting polyimides show high T (≥500 °C) and above 92.1% char yield at 800 °C both in nitrogen and air atmosphere due to the incorporation of the bulky carborane cages. Aging studies, performed at 400 and 500 °C for 5 h in air on a carborane-containing polyimide and a carborane-free polyimide, show that the polyimide with carborane groups possesses excellent thermo-oxidative stability. Moreover, the novel polyimides exhibit constant and relatively low coefficient of thermal expansion values over a wide range of temperature, indicative of a remarkable dimensional stability. Thus, this study clearly demonstrates the viability of the incorporation of carborane cages to access polyimide thermosets with ultrahigh T and thermo-oxidative stability.

Soluble Polyimides Bearing (cis, trans)-Hydrogenated Bisphenol A and (trans, trans)-Hydrogenated Bisphenol A Moieties: Synthesis, Properties and the Conformational Effect

“…Generally, according to the Kuhn and Paul J. Flory theories [23], the T g of polymers are mainly determined by the rigidity of repeating units and the molecular chain packing. No apparent T g of PI-2 or PI-3 was found in DSC curves, implying that the HBPA moiety possessed a certain degree of rigidity [24]. As shown in the DMA curves, both PI-1 (2a/ODPA, 247 °C) and PI-3 (2a/BPDA, 256 °C) possessed a lower T g than that of PI-4 (2a/6FDA, 276 °C), which can be attributed to the larger steric limitations imparted by the sp 3 -swivel moiety of trifluoromethyl in 6FDA [25].…”

Optically Transparent and Thermal‐Stable Polyimide Films Derived from a Semi‐Aliphatic Diamine: Synthesis and Properties

“…Over the past few decades, polyimides (PIs) were widely used in various high‐tech fields on account of their excellent comprehensive performance (i.e., thermal stability, low dielectric constants, remarkable mechanical property, and so on) 1–3. However, the drawbacks of deep color and poor processability of conventional aromatic PIs seriously limited their applications in modern optoelectronic field, especially in flexible electronic and display technology.…”

“…DOI: 10.1002/macp.201900506 dielectric constants, remarkable mechanical property, and so on). [1][2][3] However, the drawbacks of deep color and poor processability of conventional aromatic PIs seriously limited their applications in modern optoelectronic field, especially in flexible electronic and display technology. Generally, the present of intramolecular and intermolecular charge transfer complexes (CTC) are considered to cause the deep color of PIs, and the rigid backbones lead to the insolubility and infusibility of PIs.…”

One-Pot Synthesis of B-Aryl Carboranes with Sensitive Functional Groups Using Sequential Cobalt- and Palladium-Catalyzed Reactions

“…Aryl derivatives of icosahedral carboranes C 2 B 10 H 12 ( Figure 1) are of interest for a wide variety of applications, starting with medical chemistry [1][2][3][4] and ending with the development of new materials [5][6][7][8][9][10][11][12]. This necessitates the development of new convenient methods for their synthesis.…”