The present application provides diamine compounds, polyimide acids, polyimides, and preparation methods therefor and uses thereof. The diamine compound has a chemical structural formula represented by formula (I),

##STR00001## wherein R.sub.1 and R.sub.2 are independently selected from a single bond, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted alkynylene, substituted or unsubstituted arylene, substituted or unsubstituted arylenealkyl, substituted or unsubstituted heteroarylene, substituted or unsubstituted heteroarylenealkyl, or substituted or unsubstituted alicylidene.

A polyimide which is obtained by a reaction of an aromatic diamine having a 1,1,1-trifluoro-2,2-ethanediyl group (C(CF.sub.3)H), as a linkage skeleton, with a tetracarboxylic dianhydride is easily dissolved in an organic solvent and exhibits excellent film forming properties. In addition, the thus-obtained polyimide can be used for an optical film and a display device.

The present application relates to a polyamic acid composition, a method for preparing the polyamic acid composition, a polyimide comprising the same, and a coating material comprising the same, which provides a polyamic acid composition capable of implementing a low permittivity and heat resistance, and insulation properties and mechanical properties in a harsh condition such as a high temperature simultaneously, a method for preparing the polyamic acid composition, a polyimide comprising the same and a coating material including the same.

The disclosure relates to a method for producing a polyamic acid-containing liquid, including obtaining a polyamic acid-containing liquid that contains a polyamic acid, by using a prepolymer-containing liquid containing an amic acid prepolymer, a diamine, and a tetracarboxylic dianhydride.

Provided are a polyimide film, preparation method, and application thereof. The polyimide film is a colorless transparent film with low thermal expansion. The polyimide film is obtained by taking a mixture of rigid aromatic diamine and fluorine-containing aromatic diamine, a mixture of rigid aromatic tetracarboxylic dianhydride and fluorine-containing aromatic tetracarboxylic dianhydride as raw materials, mixing the raw materials to obtain a resin solution, and then conducting imidizing and post-treating. The polyimide film not only has excellent transparency, but also has the advantages of low thermal expansion, high modulus, high glass transition temperature, and so on, and can be well applied to a flexible optoelectronic display substrate, a flexible printed circuit board, or an electronic packaging substrate.

An anhydride compound, polyimide, and thin film are provided. The anhydride compound has a chemical structure of ##STR00001##
wherein R.sup.1 is ##STR00002##
each of R.sup.4 is independently C.sub.1-6 alkylene group, m is an integer of 0 to 10, and m is an integer of 1 to 10; n is an integer of 1 to 10, each of R.sup.2 is independently hydrogen, saturated or unsaturated C.sub.1-6 hydrocarbon group, CF.sub.3, silanol group, silyl group, or Al(OH).sub.3; and R.sup.3 is ##STR00003##
silanol group, silyl group, or Al(OH).sub.3. The anhydride compound can be reacted with a diamine compound to form a polyimide.

The present invention has the effect of making it possible to produce 1,1,1-trifluoro-2,2-bisarylethane efficiently by a simple procedure by condensing a mixture of fluoral and hydrogen fluoride with an aryl compound under anhydrous conditions. The purity of the 1,1, 1-trifluoro-2, 2-bisarylethane obtained can be raised by a simple purification method such as crystallization or distillation. The obtained 1,1,1-trifluoro-2,2-bisarylethane can be increased in purity by a simple purification method such as crystallization operation or distillation.

A method is capable of producing polyimide hollow particles does not require the use of template particles, does not require conditions of a high temperature and a high pressure, and is capable of producing polyimide hollow particles having excellent heat resistance. A polyimide hollow particle with excellent heat resistance which is obtained by such a production method is provided. A production method for polyimide hollow particles each having a shell portion and a hollow portion surrounded by the shell portion, including: preparing an inner oil phase containing polyamic acid fine particles and a solvent; preparing an outer oil phase containing a hydrocarbon-based solvent and at least one selected from the group consisting of a compound having a siloxane bond and a silicon dioxide; and carrying out a chemical imidization reaction in an emulsion prepared from the inner oil phase and the outer oil phase.

A binder, including a polyamide polymer containing repeating structural units A shown in formula (I) and repeating structural units B shown in formula (II), in which R.sub.1 is an aryl group not containing amide groups and amino groups, R.sub.2 includes an aryl group containing at least one amide groups or at least one amino groups, and a mole ratio of the repeating structural units A to the repeating structural units B is (2:1) to (6:1).

An aerogel with a polyimide matrix and associated methods are disclosed. In one example, the aerogel includes linear polyimide molecules with high molecular weight.