Thermomechanical characterization of thermoplastic polyimide–polyurea to improve the chain interaction via internal hydrogen bonds

Abstract

Recently, we have studied polyimides (PIs) synthesized by incorporating an aromatic diamine monomer with a methylene linker, 4,4 0 -methylenebis(2,6-dimethylaniline), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. In this report, we incorporate a urea linkage into these materials in order to observe the effect of additional hydrogen bonding. The polymers are designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links. Herein, we demonstrate that the addition of 1,6 hexamethylene diisocyanate and the increase of hydrogen bonds at the urea linkage can be used to improve the thermal and mechanical properties of the PI. Furthermore, the imide ring is an important component to maintain the thermal stability characteristics in polyimidepolyurea hybrids. The polymers were characterized by FTIR, thermomechanical and calorimetric analysis, microhardness, and tensile testing.

Fabrication and biological investigation of a novel star polymer based on magnetic cyclic aromatic polyimide chains

“…In the Fourier transform infrared (FTIR) spectrum of polyimides, distinctive absorption bands are observed at wavenumbers of around 1100 cm −1 and 730 cm −1 . The absorption band at 1100 cm −1 is attributed to the out-of-plane C–N bending vibration of the (O=C)2–N group in the imide ring 35 , 36 , while the absorption band at 730 cm −1 is typically attributed to the CN imide ring deformation 37 , 38 . These C–N bending motions are characteristic features of the imide functional group, which is present in the backbone of polyimides.…”

Progress of research on the bonding-strength improvement of two-layer adhesive-free flexible copper-clad laminates

“…The lm and copper foil were laminated by hot lamination, and FCCLs with a peel strength of 1.22 N mm −1 were obtained at a hot-pressing temperature of 360 °C and a hot-pressing time of 60 s. 20 TPI and PI have good compatibility because of their similar structure. 105,106 When asymmetric biphenyl-tetracarboxylic acid dianhydride was introduced into the molecular structure of TPI, the packing density and interaction force between molecular chains decreased. 107,108 TPI with increased molecular chain mobility can diffuse thoroughly on the PI lm, and the adhesion between the two is good.…”

Synthesis of Novel Nonisocyanate Poly(imide-urea)s from CO2-based Polyureas

“…Polyimides, renowned for their exceptional mechanical performance, good thermal stability, and antisolvent properties, serve a wide application in aerospace, defense, optoelectronics, and gas separation membrane. − However, traditional polyimides are typically cured at 300–400 °C to ensure sufficient thermal and mechanical properties, such a high processing temperature has limited their application . Consequently, high-performance PI materials with low imidization temperatures has become a concern in the fields such as electronics, advanced packaging, and semiconductor. , Moreover, the high glass transition temperature ( T g ) and poor solubility limit their processing and molding capacities. − To address these limitations, hybridization methodology, combining different polymeric structures, has emerged as a common approach to synthesize novel polyimide composite polymers. The synthesized polyurea-polyimide composites exhibit improved properties with thermal stability and mechanical properties superior to those of PUa or polyimide. ,,− For the preparation of poly­(imide-urea)­s (PIUs), various routes were explored.…”

“…Consequently, high-performance PI materials with low imidization temperatures has become a concern in the fields such as electronics, advanced packaging, and semiconductor. , Moreover, the high glass transition temperature ( T g ) and poor solubility limit their processing and molding capacities. − To address these limitations, hybridization methodology, combining different polymeric structures, has emerged as a common approach to synthesize novel polyimide composite polymers. The synthesized polyurea-polyimide composites exhibit improved properties with thermal stability and mechanical properties superior to those of PUa or polyimide. ,,− For the preparation of poly­(imide-urea)­s (PIUs), various routes were explored. For example, PIUs could be synthesized from an isocyanate-terminated polyimide prepolymer and an amine-terminated PUa prepolymer, where the isocyanate-terminated polyimide prepolymer was prepared by reacting 4,4′-diphenylmethane diisocyanate (MDI) with dianhydrides and the amine-terminated PUa prepolymer was prepared by reacting MDI with diamine .…”