The present disclosure relates to a polyimide precursor composition comprising an antic acid ester oligomer of formula (I):

##STR00001## wherein r, R.sub.x, G, P and R are as defined in the specification. Also, a use of the polyimide precursor composition and a polyimide made from the polyimide precursor composition.

The present disclosure relates to a polyimide precursor composition comprising an antic acid ester oligomer of formula (I):

##STR00001## wherein r, R.sub.x, G, P and R are as defined in the specification. Also, a use of the polyimide precursor composition and a polyimide made from the polyimide precursor composition.

A polybenzimidazole (PBI) resin including a polybenzimidazole oligomer having at least two reactive end groups is provided. Also provided is a method of making a polybenzimidazole oligomer with at least two reactive end groups including the steps of reacting a tetraamine, a dicarboxylic component, and a reactive end group moiety in a solvent at a temperature greater than room temperature for a period of time; precipitating the oligomer from the solvent after reacting; and removing any reaction by-products from the oligomer after precipitating. A method of making a PBI molded article and a PBI molded article are also provided.

A polybenzimidazole (PBI) resin including a polybenzimidazole oligomer having at least two reactive end groups is provided. Also provided is a method of making a polybenzimidazole oligomer with at least two reactive end groups including the steps of reacting a tetraamine, a dicarboxylic component, and a reactive end group moiety in a solvent at a temperature greater than room temperature for a period of time; precipitating the oligomer from the solvent after reacting; and removing any reaction by-products from the oligomer after precipitating. A method of making a PBI molded article and a PBI molded article are also provided.

The present invention provides benzamidazole compounds and methods of using the compounds as galectin-1 inhibitors.

The present invention provides benzamidazole compounds and methods of using the compounds as galectin-1 inhibitors.

A polymer electrolyte membrane of the present disclosure comprises a perfluorosulfonic acid resin (A), wherein the polymer electrolyte membrane has a phase-separation structure having a phase where fluorine atoms are detected in majority and a phase where carbon atoms are detected in majority, in an image of a membrane surface observed under an SEM-EDX, and the polymer electrolyte membrane has a phase having an average aspect ratio of 1.5 or more and 10 or less in an image of a membrane cross-section observed under an SEM.

There is provided a method of forming a cross-linked polymeric membrane, the method comprising: contacting a polymeric membrane with a cross-linking solution to form the cross-linked polymeric membrane, wherein the crosslinking solution comprises a cross-linker comprising at least one acyl halide functional group dissolved in a polar protic solvent. There is also provided a cross-linked polymeric membrane. In a preferred embodiment, hollow fiber polybenzimidazole (PBI) is crosslinked by trimesoyl chloride (TMC) or isophthaloyl chloride (I PC) in a solvent of ethanol or isopropyl alcohol (IPA).

There is provided a method of forming a cross-linked polymeric membrane, the method comprising: contacting a polymeric membrane with a cross-linking solution to form the cross-linked polymeric membrane, wherein the crosslinking solution comprises a cross-linker comprising at least one acyl halide functional group dissolved in a polar protic solvent. There is also provided a cross-linked polymeric membrane. In a preferred embodiment, hollow fiber polybenzimidazole (PBI) is crosslinked by trimesoyl chloride (TMC) or isophthaloyl chloride (I PC) in a solvent of ethanol or isopropyl alcohol (IPA).

The invention relates to a method for preparing polybenzimidazoles of formula (1) or (2) below, wherein n and m are each 1:

##STR00001##

by polycondensation of corresponding tetracarboxylic acids or dianhydrides and tetraamines by jointly heating the reactants, characterized in that
the preparation of polybenzimidazoles of formula (1) or (2) is carried out by using tetracarboxylic acids as starting material and substantially without the formation of any by-products, wherein a) first, a stoichiometric salt is formed from the tetracarboxylic acid and the tetraamine; b) polycondensation is carried out under hydrothermal conditions by heating the stoichiometric salt obtained in step a), in water as a solvent and under pressure, to temperatures above 100 C., wherein the values of n and m and, thus, the molecular weight and/or the extent of cyclization in the polycondensate obtained, are/is regulated by means of the temperature and/or the duration of the polycondensation; and c) optionally, a solvent-free thermal treatment of the polycondensate is carried out in order to achieve complete cyclization.