A transparent polyimide mixture is disclosed. The transparent polyimide mixture includes a transparent polyimide, an additive, and a solvent. A molecular chain of the transparent polyimide includes an active hydrogen atom. The additive includes a carbodiimide group. An equivalent ratio of the active hydrogen atom and the carbodiimide group is in a range of 1:0.8 to 1:1.2. A method for preparing the transparent polyimide mixture, a transparent polyimide film, and a method for preparing a transparent polyimide film are also disclosed.

A transparent polyimide mixture is disclosed. The transparent polyimide mixture includes a transparent polyimide, an additive, and a solvent. A molecular chain of the transparent polyimide includes an active hydrogen atom. The additive includes a carbodiimide group. An equivalent ratio of the active hydrogen atom and the carbodiimide group is in a range of 1:0.8 to 1:1.2. A method for preparing the transparent polyimide mixture, a transparent polyimide film, and a method for preparing a transparent polyimide film are also disclosed.

The invention relates to a process for preparing a semi-aromatic polyamide from diamine and dicarboxylic acid, comprising steps of •(i) dosing a liquid diamine to an agitated powder comprising an aromatic dicarboxylic acid thereby forming a powder comprising a diamine/dicarboxylic acid salt (DD-salt), and •(ii) solid-state polymerizing the DD-salt to obtain the polyamide.

The invention relates to a process for preparing a semi-aromatic polyamide from diamine and dicarboxylic acid, comprising steps of •(i) dosing a liquid diamine to an agitated powder comprising an aromatic dicarboxylic acid thereby forming a powder comprising a diamine/dicarboxylic acid salt (DD-salt), and •(ii) solid-state polymerizing the DD-salt to obtain the polyamide.

An object is to provide a polyamic acid resin composition that can form a varnish with a low viscosity and serves to produce, through curing, coat film with good mechanical characteristics. Another object is to provide a polyamic acid resin composition in which the acid anhydride terminal group is low in reactivity with diamine and which can give a varnish that does not suffer significant precipitation of diamine. These objects can be met by a polyamic acid resin composition that contains: (a) polyamic acid and (b) a compound as represented by chemical formula (1). (In Chemical formula (1), Z is a di- or higher-valent organic group containing 2 or more carbon atoms, V is a structure as represented by chemical formula (2), and k is an integer of 2 or more.) (In In Chemical formula (2), δ represents oxygen or sulfur atom and W represents an electron-withdrawing group, and R.sup.11 and R.sup.12 represent independently a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms.

An object is to provide a polyamic acid resin composition that can form a varnish with a low viscosity and serves to produce, through curing, coat film with good mechanical characteristics. Another object is to provide a polyamic acid resin composition in which the acid anhydride terminal group is low in reactivity with diamine and which can give a varnish that does not suffer significant precipitation of diamine. These objects can be met by a polyamic acid resin composition that contains: (a) polyamic acid and (b) a compound as represented by chemical formula (1). (In Chemical formula (1), Z is a di- or higher-valent organic group containing 2 or more carbon atoms, V is a structure as represented by chemical formula (2), and k is an integer of 2 or more.) (In In Chemical formula (2), δ represents oxygen or sulfur atom and W represents an electron-withdrawing group, and R.sup.11 and R.sup.12 represent independently a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms.

A self-healing capacitor comprises a first electrode, a second electrode, and a dielectric layer disposed between said first and second electrodes and having first surface faced the first electrode and second surface faced the second electrode. At least one of the electrodes can include metal foam. The dielectric layer can have electrically conductive channels that each has an exit point located on the first surface of the dielectric layer and another exit point located on the second surface of the dielectric layer. The electrodes can include local contact breakers each of which is located within the electrode at an interface between the dielectric layer and the electrode and opposite at least one exit point of each electrically conductive channel in the dielectric layer. The local contact breakers can prevent electric current through the conductive channels in dielectric layer.

A self-healing capacitor comprises a first electrode, a second electrode, and a dielectric layer disposed between said first and second electrodes and having first surface faced the first electrode and second surface faced the second electrode. At least one of the electrodes can include metal foam. The dielectric layer can have electrically conductive channels that each has an exit point located on the first surface of the dielectric layer and another exit point located on the second surface of the dielectric layer. The electrodes can include local contact breakers each of which is located within the electrode at an interface between the dielectric layer and the electrode and opposite at least one exit point of each electrically conductive channel in the dielectric layer. The local contact breakers can prevent electric current through the conductive channels in dielectric layer.

A metal adsorbent that includes silver-decorated graphene nano-platelets and a polymer matrix that comprises polyamide, wherein the metal adsorbent is a highly porous material with a specific surface area of 200 to 300 m.sup.2/g and an average pore size of 50 to 100 Å, which effective removes heavy metals and cations from a liquid. Various embodiments of the metal adsorbent and a method of making thereof are also provided.

A polymer dispersion is disclosed. The polymer dispersion includes a liquid crystal polymer powder, a polyamide acid, and a solvent. A solid content of the polymer dispersion includes the liquid crystal polymer powder and the polyamide acid. The liquid crystal polymer powder has a mass ratio of 20% to 30% in the solid content. The polyamide acid has a mass ratio of 70% to 80% in the solid content. The polyamide acid is obtained by mixing two kinds of diamines and two kinds of dianhydrides together, causing the diamines and the dianhydrides to be polymerized with each other. Both two kinds of diamines and two kinds of dianhydrides comprise a liquid crystal structure and a flexible structure respectively. A method of preparing the polymer dispersion, and a method for preparing a polymer composite film using the polymer dispersion are also disclosed.