The present disclosure provides a thin film material and a manufacturing method thereof. The manufacturing method of the thin film material comprises: a compound A and a first reactant reacting to form a compound B; the compound B and a second reactant reacting to form a compound C; the compound C and a third reactant reacting to form a polymer D; the polymer D reacting to obtain a mixture including a polymer F or a polymer H; and a solution including the polymer F or the polymer H forming the polymer F or the polymer H on a substrate.

A salt composition includes at least one ammonium carboxylate salt obtained from: (a) at least one aromatic compound comprising 2 anhydride functional groups and/or its carboxylic acid and/or ester derivatives; and (b) one or more aliphatic diamines in which said aliphatic diamine or diamines are chosen from the diamines of formula (I) NH.sub.2RNH.sub.2 with R being a saturated aliphatic divalent hydrocarbon radical, the two amine functional groups of which are separated by 4 to 6 carbon atoms and 1 or 2 hydrogen atoms of the divalent radical of which are replaced by 1 or 2 methyl and/or ethyl groups; and optionally the diamines of formula (II) NH.sub.2RNH.sub.2 with R being a saturated or unsaturated and aliphatic, cycloaliphatic or arylaliphatic divalent hydrocarbon radical, which optionally comprises heteroatoms; and at least one chain-limiting compound chosen from monoamines, monoacids or diacids in the , positions.

A system comprises an extrusion head to selectively extrude a bead of a precursor solution onto a target road on a substrate within a build area, the precursor solution comprising a polyimide precursor compound in a solvent, an actuator coupled to the extrusion head to move the extrusion head, a control system coupled to the actuator to control the extrusion head along the target road and selectively dispense the precursor solution to the extrusion head, and an environmental system configured to accommodate the target road during fabrication, the environmental system configured to expose the dispensed precursor solution to a temperature selected to evaporate solvent from the solution to initiate polymerization of the polyimide precursor compound to form at least a portion of a polyimide part.

A solvothermal synthesis process for polyimides is provided. The process uses solution polymerization of monomers in an appropriate solvent, by mixing the solvent and the monomers and heating the mixture under pressure at temperatures exceeding the respective boiling point at normal pressure. The process produces essentially completely crystalline polyimides by a) mixing and heating the solvent and the monomers by either (i) heating the solvent up to solvothermal conditions and subsequently adding the monomers to initiate the reaction, or (ii) mixing the monomers with the solvent and heating the mixture up to solvothermal conditions within a period of 5 min, the reaction temperature TR being held below the polymerization temperature or the solid-state polymerization temperature TP of the monomers during the polymerization; and b) carrying out the solution polymerization until essentially complete conversion is achieved.

A polyimide polymer represented by the following formula 1 is provided. ##STR00001##
In formula 1, Ar is ##STR00002##
Ar is ##STR00003##
A is ##STR00004##
and 0<X<0.38.

Reactive extrusion can be used in a continuous, solvent-less preparation of imide oligomers involving two competing reactions among three ingredients, the first reaction between a dianhydride and a diamine and the second reaction between an endcap and the same diamine. The imide oligomer can form a composite via conventional production methods or via formation of a film from imide oligomer re-melted in an extruder before being impregnated into tape or fabric.

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.

A polyetherimide of improved color and processes for preparing the polyetherimide are disclosed.

A treatment fluid and a plurality of proppant particles, which comprise a cross-linked polyimide aerogel, are provided for use in the fracking of subterranean formations. The cross-linked polyimide aerogel can have a porosity above about 80% and a compressive strength in the range from about 10,000 psi to about 50,000 psi. The cross-linked polyimide aerogel can be derived by cross-linking oligomers, wherein each oligomer comprises a base unit of one or more dianhydrides and one or more diamines.

The present disclosure is directed to methods of forming polyamic acid, polyamic acid metal salt, and polyimide gels under aqueous conditions, the methods utilizing water-soluble carbonate or bicarbonate salts. These gels may be converted to aerogels or xerogels, which may further be converted to carbon aerogels or xerogels. Such carbon aerogels or xerogels have the same physical properties as carbon aerogels or xerogels prepared from polyimide aerogels obtained according to conventional methods, i.e., organic solvent-based methods.