Present invention is related to a polyimide of formula as following:

##STR00001##

and a ketone-containing alicyclic dianhydride of formula as following:

##STR00002##

wherein: R1, R2, R3, R4 denote hydrogen atom or carbon containing functional group with carbon number at a range of 1-4; R5 denotes diamine group; and n equals to any positive integer.

The present disclosure discloses a high-whiteness polyimide microfiber and a preparation method thereof and use. The polyimide fiber includes polyimide obtained from the reaction of wholly alicyclic dianhydride HTDA and an aromatic diamine monomer containing methyl or trifluoromethyl by chemical imidization. In the present disclosure, the polyimide microfiber has both excellent heat-resistant stability and spinning film-forming property, and the fabric has ultra-high whiteness. The microfiber fabric prepared from the polyimide fiber may be used as a component with high-temperature resistant and high-whiteness in personal protective equipment such as mask and protective clothing, and also may be used as an electronic component in the high-tech field such as aerospace, optoelectronic, microelectronic and automobile.

A modified polyimide resin containing a structure represented by general formula (I) below. A polyimide resin containing: a structural unit A derived from a tetracarboxylic dianhydride; and a structural unit B derived from a diamine compound, wherein the structural unit A contains a structural unit derived from a compound having a specific structure in a proportion of 60 mol % or greater.

##STR00001##

A polyimide is provided, which contains at least one repeating unit selected from a group consisting of the following general formulas, M, N, and O:

##STR00001##

X is a residue derived from TCA represented by formula I. Y.sub.1 is a residue derived from a diamine with a cardo structure. Y.sub.2 is a residue derived from a diamine with the structure of a benzene ring, biphenyl, phenylbenzimidazole or phenylbenzoxazole. Y.sub.3 is a residue derived from a diamine with an ether or an ester group.

##STR00002##

Disclosed are a polyimide-based film and a method of producing the same, and more particularly, a polyimide-based film having excellent surface evenness and suppressed waviness due to low Kc of 1.55 or less and a method of producing the same.

A polyimide precursor includes a repeating unit of formulae (I) and (II):

##STR00001## where R1 and R3 are each a tetravalent group of a tetracarboxylic dianhydride residue, and R2 and R4 are respectively a divalent group of a residue of a first-type diamine and a divalent group of a residue of a second-type diamine. The first-type diamine is represented by formula (III), and the second-type diamine is represented by formula (IV). A resin composition including the polyimide precursor, a polyimide formed from the polyimide precursor, and use of the polyimide are also disclosed.

Provided are a polyamideimide precursor, a polyamideimide prepared therefrom, and a polyamideimide film including the same. Specifically, the polyamideimide film according to an exemplary embodiment includes a polyamideimide derived from a combination of specific compositions to implement a high modulus and excellent optical properties.

The invention discloses a remoldable shape memory bismaleimide resin and its application. The preparation method includes blending 2-allylphenyl glycidyl ether and adipic acid in acetonitrile, carrying out an esterification reaction under the condition of quaternary ammonium salt as a catalyst to obtain bis(3-(2-allylphenoxy)-2-hydroxypropyl)adipate containing a reversible dynamic group; then uniformly mixing bis(3-(2-allylphenoxy)-2-hydroxypropyl)adipate and bismaleimide, curing to obtain the remoldable shape memory bismaleimide resin. The prepared remoldable shape memory bismaleimide resin is not only excellent heat resistance and mechanical properties, but also can be remolded under hot pressing conditions. The preparation method of the remoldable shape memory bismaleimide resin has the advantages of wide raw material sources and simple process, and has a wide application prospect in the fields of aerospace, transportation, electronic information, new energy, insulated electrical industry and the like.

The present invention relates to a diamine, and a polymer and film produced using the same. Specifically, the diamine may be significantly effectively used as a monomer for producing a polyimide-based film that is colorless and transparent and has improved mechanical strength.

An embodiment relates to a diamine compound, a polymer including a structural unit derived therefrom, a composition for forming a polyimide film including the polymer, and a polyimide film prepared by using the composition. Specifically, the diamine compound according to an embodiment may be very usefully used as a monomer for preparing a polyimide film that is colorless and has an improved mechanical strength.