Abstract: A poly(amide-imide) copolymer that is a reaction product of a diamine represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, a dicarbonyl compound represented by Chemical Formula 3, and a tetracarboxylic acid dianhydride represented by Chemical Formula 4, a composition for preparing the poly(amide-imide copolymer, and an article including the copolymer, e.g., a film are provided: wherein, in Chemical Formulae 1 to 4, Ra, L1, L2, n1, A, R3, X, R10, R12, R13, n7 and n8 are the same as defined in the specification.

Abstract: Disclosed is a window film for a display device including a light transmitting substrate including a polyamide including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a hard coating layer laminated on one surface of the light transmitting substrate: in Chemical Formula 1 and Chemical Formula 2, each of A1, A2, B, and D is the same as defined in the detailed description.

Abstract: A laminated film which includes a first layer including a poly(amide-imide) copolymer, and a second layer laminated on at least one surface of the first layer. The second layer includes a poly(amide-imide) copolymer, polyimide, or a combination thereof, which has an amide content of less than or equal to about 30 mol %. The poly(amide-imide) copolymer included in the first layer has a weight average molecular weight of about 30,000 grams/mole to about 200,000 grams/mole, and the polyimide, the poly(amide-imide) copolymer, or the combination thereof, of the second layer has a weight average molecular weight of about 10,000 grams/mole to about 50,000 grams/mole, and the composition for preparing the laminated film.

Abstract: A poly(amide-imide) copolymer including an amide structural unit having an amide bond in a polymer main chain and an imide structural unit having an imide bond in a polymer main chain, wherein at least one imide structural unit includes a moiety cross-linked to an adjacent polymer main chain through an amide bond.

Abstract: A poly(amide-imide) copolymer including an amide structural unit having an amide bond in a polymer main chain and an imide structural unit having an imide bond in a polymer main chain, wherein at least one imide structural unit includes a moiety cross-linked to an adjacent polymer main chain through an amide bond.

Abstract: A composition for preparing an electro-optic material including a first polyimide having a high molecular weight, and a second polyimide having a lower molecular weight and including a structural unit including a chromophore functional group in the side chain, an electro-optic material including the composition, an electro-optic device including the electro-optic material, and a method of preparing the electro-optic material.

Abstract: A laminated film including a first film; and a second film disposed on the first film, wherein a tensile modulus of the second film is greater than or equal to a tensile modulus of the first film, and a transmittance of the first film is greater than or equal to a transmittance of the second film, provided that at least one of the tensile modulus of the first film and the tensile modulus of the second film are not equal or the transmittance of the first film and the transmittance of the second film are not equal.

Abstract: A composition for preparing an article including a polyimide or poly(imide-amide) copolymer, the composition including (1) at least one of (i) a polyimide, a polyamic acid, or a poly(imide-amic acid) including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2; and (ii) a poly(imide-amide) copolymer, a poly(amic acid-amide) copolymer, or a poly(imide and amic acid-amide) copolymer including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a structural unit represented by Chemical Formula 3, and (2) a compound having a maximum absorption wavelength at about 570 nm or more in a visible radiation region: wherein in Chemical Formulae 1 to 3, A, B, D, and E are the same as defined in the detailed description.

Abstract: A laminated film including a first film; and a second film disposed on the first film, wherein a tensile modulus of the second film is greater than or equal to a tensile modulus of the first film, and a transmittance of the first film is greater than or equal to a transmittance of the second film, provided that at least one of the tensile modulus of the first film and the tensile modulus of the second film are not equal or the transmittance of the first film and the transmittance of the second film are not equal.

Abstract: A poly(amide-imide) copolymer that is a reaction product of a substituted or unsubstituted aromatic diamine having a maximum absorption wavelength in a range from 500 nanometers (nm) to 650 nm in a visible light region, a diamine represented by Chemical Formula 1, a dicarbonyl compound represented by Chemical Formula 2, and a tetracarboxylic acid dianhydride represented by Chemical Formula 3: wherein, in Chemical Formulae 1 to 3, A, R3, R10, R12, R13, X, n7 and n8 are the same as defined in the specification.

Abstract: A laminated film which includes a first layer including a poly(amide-imide) copolymer, and a second layer laminated on at least one surface of the first layer. The second layer includes a poly(amide-imide) copolymer, polyimide, or a combination thereof, which has an amide content of less than or equal to about 30 mol %. The poly(amide-imide) copolymer included in the first layer has a weight average molecular weight of about 30,000 grams/mole to about 200,000 grams/mole, and the polyimide, the poly(amide-imide) copolymer, or the combination thereof, of the second layer has a weight average molecular weight of about 10,000 grams/mole to about 50,000 grams/mole, and the composition for preparing the laminated film.

Abstract: Disclosed is a window film for a display device including a light transmitting substrate including a polyamide including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a hard coating layer laminated on one surface of the light transmitting substrate: in Chemical Formula 1 and Chemical Formula 2, each of A1, A2, B, and D is the same as defined in the detailed description.

Abstract: A composition for preparing an electro-optic material including a first polyimide having a high molecular weight, and a second polyimide having a lower molecular weight and including a structural unit including a chromophore functional group in the side chain, an electro-optic material including the composition, an electro-optic device including the electro-optic material, and a method of preparing the electro-optic material.

Abstract: A composition for preparing poly(imide-benzoxazole) copolymer is described, where the copolymer include: a tetracarboxylic acid dianhydride represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a diamine represented by Chemical Formula 3: wherein definitions of groups and variables in Chemical Formulae 1 to 3 are the same as described in the specification.

Abstract: A poly(amide-imide) copolymer that is a reaction product of a diamine represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, a dicarbonyl compound represented by Chemical Formula 3, and a tetracarboxylic acid dianhydride represented by Chemical Formula 4: wherein, in Chemical Formulae 1 to 4, L1, R1 to R3, R10, R12, R13, a, b, c, d, A, X, n7 and n8 are the same as defined in the specification.

Abstract: A poly(amide-imide) copolymer including an amide structural unit having an amide bond in a polymer main chain and an imide structural unit having an imide bond in a polymer main chain, wherein at least one imide structural unit includes a moiety cross-linked to an adjacent polymer main chain through an amide bond.

Abstract: A polyimide film having tensile modulus of greater than or equal to about 5 gigapascals, and yellowness index of less than 2.5, when measured at a thickness of the film between 50 micrometers to 100 micrometers, wherein the polyimide film is a reaction product of a combination including an aromatic dianhydride and an aromatic diamine, wherein the aromatic dianhydride includes 4,4?-oxydiphthalic anhydride.

Abstract: A poly(amide-imide) copolymer film having a tensile modulus of greater than or equal to 5.4 GPa, and a yellowness index of less than or equal to 3.6, wherein the poly(amide-imide) copolymer film is a reaction product of an aromatic dianhydride including biphenyl tetracarboxylic dianhydride and 4,4?-hexafluoroisopropylidene diphthalic dianhydride, an aliphatic dianhydride including 1,2,3,4-cyclobutane tetracarboxylic dianhydride, an aromatic diamine including 2,2-bis(trifluoromethyl) benzidine, and an aromatic dicarbonyl compound including terephthaloyl dichloride.

Abstract: A poly(amide-imide) copolymer including an amide structural unit having an amide bond in a polymer main chain and an imide structural unit having an imide bond in a polymer main chain, wherein at least one imide structural unit includes a moiety cross-linked to an adjacent polymer main chain through an amide bond.

Abstract: A composition for preparing an article including a polyimide or poly(imide-amide) copolymer, the composition including (1) a solution including at least one of (i) a polymer including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2; and (ii) a copolymer including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a structural unit represented by Chemical Formula 3, and (2) a metallic salt soluble in the solution of the polymer and/or the copolymer, wherein the metallic salt is a salt of a metal selected from a Group 1 element, a Group 11 element, a Group 13 element, and a Group 14 element: wherein in Chemical Formulae 1 to 3, A, B, D, and E are the same as defined in the detailed description.