A polyimide resin containing a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), a content ratio of the repeating structural unit of formula (1) with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) being 20 to 70 mol %, and the polyimide resin having a chain aliphatic group having from 5 to 14 carbon atoms at an end thereof:

wherein R.sub.1 represents a divalent group having from 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure; R.sub.2 represents a divalent chain aliphatic group having from 5 to 16 carbon atoms; and X.sub.1 and X.sub.2 each independently represent a tetravalent group having from 6 to 22 carbon atoms containing at least one aromatic ring.

Prepare a carbon molecular sieve membrane from a polyimide (e.g., a 6FDA/BPDA-DAM polyimide) that has a glass transition temperature of at least 400° C. and includes a bridged phenyl compound for separation of hydrogen and ethylene from one another whether present as a pure mixture of hydrogen and ethylene or as components of a cracked gas. Preparation comprises two sequential steps a) and b). In step a), place a membrane fabricated from defect-free fibers of the polyimide in contact with an oxygen-containing atmosphere under conditions of time and temperature sufficient to produce a pre-oxidized and pre-carbonized polymeric membrane that is insoluble in hot (110 C) n-methylpyrolidone and at least substantially free of substructure collapse. In step b) pyrolyze the pre-oxidized and pre-carbonized membrane in the presence of a purge gas under conditions of time and temperature sufficient to yield a carbon molecular sieve membrane that has at least one of a hydrogen permeance and a hydrogen/ethylene selectivity greater than that of a carbon molecular sieve membrane prepared from the same membrane using only pyrolysis as in step b).

To provide a polymer material having properties that allow the polymer material to replace a polyimide and a polyamide synthesized from a petroleum raw material, said polymer material being synthesized from a raw material derived from natural molecules. [Solution] This polymer material is obtained by polymerizing a polymer raw material comprising a dimer of 4-amino cinnamic acid or a dimer of a 4-amino cinnamic acid derivative, which are natural molecules, wherein the carboxyl group is protected by an alkyl chain. The TGA curve of a polyamide acid (PAA-1) and a polyimide (PI-1) according to the present invention is shown in FIG. 5.

There is provided a polyimide precursor which can alter the hydrophilicity/hydrophobicity of the surface of a cured film formed readily even by a low level of ultraviolet ray irradiation; and a polyimide produced from the polyimide precursor. The polyimide precursor having a structure represented by the following formula (1): ##STR00001##
where A represents a tetravalent organic group; B represents a bivalent organic group having a thiol ester bond in its main chain; R.sup.1 and R.sup.2 independently represent a hydrogen atom or a univalent organic group; and n represents a natural number.

A liquid crystal display device includes a first substrate, a first alignment layer on the first substrate, a second substrate facing the first substrate, a second alignment layer on the second substrate, and a liquid crystal layer between the first substrate and the second substrate and including liquid crystal molecules. The first alignment layer and the second alignment layer include a polymer including at least of polyamic acid, polyimide, and a combination including at least one of the foregoing polymers, and a compound including an epoxy cross-linker represented by Chemical Formula 1.

The present invention relates to a copolymer for the photoalignment of liquid crystals comprising a photoreactive group as given below in formula (I), compositions thereof, and its use for optical and electro optical devices, especially liquid crystal devices (LCDs).

Provided is a polyamide-imide film including: a polyamide-imide resin and a porphyrin-based dye. The polyamide-imide film has excellent optical properties, and, in particular, may maintain an excellent yellow index even in a repeated temperature change environment.

Provided are a polyamideimide resin, and a polyamideimide film and a window cover film including the same. More particularly, a polyamideimide resin for preparing a polyamideimide film which satisfies both optical properties and mechanical properties which are in a trade-off relationship with each other and has more improved mechanical properties than a conventional polyamideimide film, a polyamideimide film using the same, and a window cover film including the same are provided.

The present disclosure is directed to a base film having a chemically converted polyimide, a particulate polyimide matting agent and a low conductivity carbon black. The particulate polyimide matting agent is present in an amount from 1.6 to 9 weight percent of the base film.

A polymer and a resin composition thereof are provided. The polymer includes a first repeat unit represented by Formula (I) and a second repeat unit represented by Formula (II)

##STR00001##

wherein A.sup.1 is C.sub.24-48 alkylene, C.sub.24-48 alkenylene, C.sub.24-48 alkynylene, C.sub.24-48 alicyclic alkylene, C.sub.24-48 alicyclic alkenylene, or C.sub.24-48 alicyclic alkynylene. A.sup.2 and A.sup.4, independently having at least one reactive group, are independently C.sub.6-25 arylene, C.sub.4-8 cycloalkylene, C.sub.5-25 heteroarylene, divalent C.sub.7-25 alkylaryl, divalent C.sub.7-25 acylaryl, divalent C.sub.6-25 aryl ether, divalent C.sub.7-25 acyloxyaryl, or divalent C.sub.6-25 sulfonylaryl; and, A.sup.3 is substituted or unsubstituted C.sub.6-25 arylene, C.sub.4-8 cycloalkylene, C.sub.5-25 heteroarylene, divalent C.sub.7-25 alkylaryl, divalent C.sub.7-25 acylaryl, divalent C.sub.6-25 aryl ether, divalent C.sub.7-25 acyloxyaryl, or divalent C.sub.6-25 sulfonylaryl.