The present invention relates to a liquid crystal aligning agent for use as an alignment layer for liquid crystal display. More specifically, the present invention relates to a liquid crystal aligning agent capable of improving an imidization rate and thus exhibiting an excellent alignment state, a liquid crystal alignment layer comprising the same, a preparation method thereof and a liquid crystal display comprising the liquid crystal alignment layer.

The present invention relates to thermoplastic polyimides and to the synthesis thereof. The invention relates in particular to a method for manufacturing semi-aromatic thermoplastic polyimides by means of the solid-state polymerization of a solid ammonium carboxylate salt formed from an aliphatic diamine and an aromatic tetracarboxylic acid, thereby enabling powders having controlled particle sizes to be produced.

One method as described herein relates to making a high molecular weight, monoesterified polyimide polymer using a small amount of bulky diamine. These high molecular weight, monoesterified polyimide polymers are useful in forming crosslinked polymer membranes with high permeance that are useful for the separation of fluid mixtures. Another method as described herein relates to making the crosslinked membranes from the high molecular weight, monoesterified polyimide polymer containing a small amount of bulky diamine. The small amount of bulky diamine allows for formation of both the high molecular weight polyimide polymer and for covalent ester crosslinks via reaction of the carboxylic acid groups with a diol crosslinking agent. This small amount of bulky diamines reduces chain mobility or segmental motion during crosslinking and reduces large loss of permeance. As such, this method provides a crosslinked membrane with good permeance and selectivity.

One method as described herein relates to making a membrane comprising an uncrosslinked high molecular weight polyimide polymer with a small amount of bulky diamine. Also as described herein is a hollow fiber polymer membrane comprising an uncrosslinked high molecular weight polyimide polymer with a small amount of bulky diamine. The polyimide polymers include monomers comprising dianhydride monomers, diamino monomers without carboxylic acid functional groups, and optionally diamino monomers with carboxylic acid functional groups, wherein 2 to 10 mole % of the diamino monomers are bulky diamino compounds and the ratio of diamino monomers with carboxylic acid functional groups to diamino monomers without carboxylic acid functional groups is 0 to 2:3. These uncrosslinked high molecular weight polyimide polymers with a small amount of bulky diamine are useful in forming polymer membranes with high permeance and good selectivity that are useful for the separation of fluid mixtures.

One method as described herein relates to making a membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. These uncrosslinked high molecular weight, monoesterified polyimide polymers with a small amount of bulky diamine are useful in forming polymer membranes with high permeance and good selectivity that are useful for the separation of fluid mixtures. Also as described herein is a hollow fiber polymer membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. The small amount of bulky diamine allows for formation of a membrane comprising the uncrosslinked polymer that exhibits high permeance and good selectivity.

A method for using citraconic anhydride and itaconic anhydride as addition cure end caps in reactions for forming polyamic acid oligomers and polyimide oligomers, is provided. Prepregs and high temperature adhesives made from the resulting oligomers, as well as, high temperature, low void volume composites made from the prepregs, are also provided.

Polyimides containing a backbone with at least one nanoparticle component and made from oligomers having endcaps that are difunctional or a mix of di- and monofunctionality are provided. The endcaps may be nadic or phenylethynyl. The backbone may be wholly inorganic or made from a mixture of inorganic and organic groups. The oligomers may be created in-situ using standard polymerization of monomeric reactants chemistry using a solvent or may be provided as a pre-imidized compound that may be either a solid or liquid. It is believed that the nanoparticle component of the polymer backbone provides superior thermo-oxidative stability verses unmodified organic backbones. It is further believed that providing difunctional or a mixture of di- and monofunctional endcaps allows for increased crosslinking to provide improved strength and stiffness verses wholly monofunctional endcapped oligomers for polyimides. The nanoparticle is part of the backbone of the polymer and not solely a pendant group.

Provided is a varnish including 1 to 500 parts by weight of an aromatic tetracarboxylic acid diester (A) represented by General Formula (1), 1 to 450 parts by weight of 2-phenyl-4,4-diaminodiphenyl ether (B), 1 to 100 parts by weight of a 4-(2-phenylethynyl)phthalic acid monoester (C) represented by General Formula (2), and 100 parts by weight of an organic solvent having a boiling point of 150 C. or less at 1 atmosphere or a mixture of two or more of the organic solvents (D). The components (A), (B), and (C) are dissolved in the varnish.

##STR00001##

(In the formula, R.sub.1 is an aromatic tetracarboxylic acid diester residue; R.sub.2 and R.sub.3 are the same or different and are an aliphatic organic group or an aromatic organic group.)

##STR00002##

(In the formula, R.sub.4 and R.sub.5 are a hydrogen atom, an aliphatic organic group, or an aromatic organic group.)

The present invention pertains to the use of a polyimide aerogel, wherein the polyimide aerogel comprises polyimide spheres having a diameter of 250 nm to 20 m, as an insulating, sorption or filter material, as well as to methods for the preparation of the same.

According to one embodiment, a varnish for a photo alignment film includes a first polyamic acid-based compound, which is a polyamic acid or a polyamic acid ester, in an organic solvent. The first polyamic acid-based compound has terminal skeletons containing no primary amino group.