A method of making a polyetherimide includes melt mixing a composition comprising an aromatic bis(ether anhydride) and a diamine to form a polyetherimide wherein melt mixing occurs at a temperature 50 to 225 C. greater than the glass transition temperature of the polyetherimide and after the composition attains a weight average molecular weight that is greater than or equal to 20% of the weight average molecular weight of the polyetherimide melt mixing occurs at a pressure less than atmospheric pressure.

A polyimide oligomer of the formula

##STR00001##

wherein G is a group having a valence of t and is connected by a covalent bond or an ionic bond, each Q is independently the same or different, and is a cation or a substituted or unsubstituted divalent C.sub.1-60 hydrocarbon group, each M is independently the same or different, and is a substituted or unsubstituted divalent C.sub.1-60 hydrocarbon group, O, C(O), OC(O), OC(O)O, NHC(O), (O)CNH, S, S(O), or S(O).sub.2, D is a phenylene, each V is independently the same or different, and is a tetravalent C.sub.4-40 hydrocarbon group, each R is independently the same or different, and is a C.sub.1-20 divalent bridging group, a C.sub.1-20 alkylene-XA, or a C.sub.6-30 arylene-XA wherein XA is a cation-anion complex, provided that at least one R is C.sub.1-20 alkylene-XA or C.sub.6-30 arylene-XA, q, m, d, p, t, and n are as provided herein.

A polyimide oligomer of formula (1a), (1b), a copolymer thereof, or a combination thereof

##STR00001##

wherein each G.sup.1 is independently the same or different, and is a cation group; each G.sup.2 is independently the same or different, and is an anion group; each D is independently the same or different, and is a single bond or C.sub.1-20 divalent hydrocarbon group; each V is independently the same or different, and is a tetravalent C.sub.4-40 hydrocarbon group; each R is independently the same or different, and is a C.sub.1-20 divalent hydrocarbon group; each n is independently the same or different, and is 1 to 1000, provided that the total of all values of n is greater than 4; and t is 2 to 1000.

The present invention relates to a branched copolymer having a polyimide polymer block bonded to each terminal of a branched polyamide functional group, and a photosensitive resin composition including the same, a photosensitive resin film, and an optical device.

The present disclosure relates to a polyimide-based block copolymer and a polyimide-based film including the same. The polyimide-based block copolymer according to the present disclosure makes it possible to provide a polyimide-based film exhibiting excellent mechanical properties while being colorless and transparent. The polyimide-based film may be used as a cover film of various flexible or foldable devices.

A graphene-based membrane and a method of producing the same are disclosed. The graphene-based membrane may include a graphene-polymer composite, wherein the graphene-polymer composite may consist of an amine functionalized graphene and a polymer containing an anhydride group as a linker for linking the amine functionalized graphene to the polymer. The graphene-based membrane may be constructed of a single-layer. A method may include reacting a polymer containing an anhydride with an amine functionalized graphene in presence of a solvent to form an intermediate product; and thermal imidizing the intermediate product to form a graphene grafted polymer composite for use in fabricating a graphene-based membrane.

Embodiments of the present disclosure describe carbocyclic pseudo Trger's base (CTB) amines. Embodiments of the present disclosure further describe microporous polymers derived from pseudo CTB amines, including, but not limited to, polyimides, CTB ladder polymers, and network porous polymers. Other embodiments describe a method of separating chemical species in a fluid composition comprising contacting a microporous polymer membrane with a fluid composition including at least two chemical species, wherein the microporous polymer membrane includes one or more of a ladder polymer of intrinsic microporosity, a microporous polyimide, and a microporous network polymer; and capturing at least one of the chemical species from the fluid composition.

The present invention provides an amic acid ester oligomer having a structure of Formula (1) or (1): ##STR00001## wherein G, P, R, R.sub.x, D, E and m are as defined in the specification. The present invention also provides a polyimide precursor composition comprising the amic acid ester oligomer, as well as a polyimide prepared from the composition.

A branched polyimide of the formula (I) wherein G is a group having a valence of t present in an amount 0.01 to 20 mol %, each Q is independently the same or different, and is a divalent C.sub.1-60 hydrocarbon group, each M is independently the same or different, and is O, C(O), OC(O), OC(O)O, NHC(O), (O)CNH, S, S(O), or S(O).sub.2, D is a phenylene, each V is independently the same or different, and is a tetravalent C.sub.4-40 hydrocarbon group, each R is independently the same or different, and is a C.sub.1-20 divalent hydrocarbon group, q is 0 or 1, m is 0 or 1, d is 0 or 1, p is 1 or 2, t is 2 to 6, and each n is independently the same or different, and is 1 to 1,000, provided that the total of all values of n is greater than 4.

##STR00001##

A branched polyimide of the formula (I) wherein G is a group having a valence of t, present in an amount of 0.01 to 10 mol %, or 0.05 to 5 mol %, or 0.1 to 4 mol %, or 0.1 to 3 mol %, each of Q, M, D, V, and R are as defined herein, q is 0 or 1, m is 0 or 1, d is 0 or 1, p is 1 or 2, t is 2 to 6, preferably 2 to 4, and each n is independently the same or different, and is 1 to 1,000, provided that the total of all values of n is greater than 4, wherein the branched polyimide has a zero-shear viscosity in a range from 500 to 15,000 Pa.Math.s, a rheology ratio of 1.1 to 5, and a strain hardening ratio of 1 to 6.

##STR00001##