Aromatic diamine with phthalonitrile pendant group, preparation method thereof and polyimides or polyamide prepared therefrom

Abstract

The invention discloses an aromatic diamine containing o-phthalonitrile side group. The structure formula of the aromatic diamine is shown as the right formula. The invention also discloses a method for preparing the aromatic diamine and polyimide and daiamid which are prepared by taking the aromatic diamine containing the o-phthalonitrile side group as one of raw materials. The o-phthalonitrile side group in the aromatic diamine is positioned on the side chain, thereby adjusting the degree of crosslinking with adjusting the polymer molecular weight and widening the application of the polyimide and the daiamid in a thick-wall composite material or a composite material element with a complicated shape and the fields of membrane material and fiber.

Description

technical field The invention belongs to the technical field of aromatic diamines and their preparation methods and polyimides or polyamides, in particular to aromatic diamines containing phthalonitrile side groups and their preparation methods and their preparation methods by containing phthalonitrile Aromatic diamines are used as monomers to prepare polyimides or polyamides containing phthalonitrile side groups. Background technique Polyimide (PI) is a class of high-performance polymers containing imide rings in the main chain. Due to its excellent thermal stability, mechanical properties, chemical inertness, dielectric properties and radiation resistance, it has long been used as a film, Commodity forms such as coatings, fibers, plastics, adhesives and resin-based composites are widely used in high-tech fields such as aerospace and electronics industries. Polyimide is prepared by polycondensation reaction using aromatic dianhydride and diamine, and its synthesis process ...

AI Technical Summary

Problems solved by technology

(1) Since the phthalonitrile unit is at the end of the polymer chain, its reactivity is limited by the molecular weight of the polymer. If the molecular weight is too large, the phthalonitrile reactivity decreases, making it difficult to form an effective crosslink (U.S.Pat. No.5,132,396), the molecular weight is too small, and the cross-linking density of the polymer is too large, which will make the polymer more brittle

(2) The molecular weight of the existing phthalonitrile-terminated polyimides is generally within the range of 2000g / mol, so its film-forming property is poor, which limits its application in the field of film materials and fibers. application

Because traditional aromatic polyamides are usually infusible and insoluble, it is difficult to process, so people have studied many modification methods to improve the processability of polyamides.

These means of modification mainly include the introduction of side groups (Meyer.M.R.Macromolecules, 24,642) on the main chain of polyamides. Although these means can significantly improve the organic solubility and processability of polyamides, due to the The reduction of rigidity, thus sacrificing the excellent thermal properties, mechanical properties and solvent resistance of polyamides, limits the application range of polyamides

Images