Amphiphilic copolymers and compositions including amphiphilic copolymers. The amphiphilic copolymers include modified maleimide subunits, for example, as illustrated by the structures of Formula I.sup.A and Formula I.sup.B. The compositions form water-soluble complexes upon association with biological material wherein such biological material can include lipids or membrane proteins. Methods for producing, purifying, analyzing, and using the compositions and complexes are provided.

Amphiphilic copolymers and compositions including amphiphilic copolymers. The amphiphilic copolymers include modified maleimide subunits, for example, as illustrated by the structures of Formula I.sup.A and Formula I.sup.B. The compositions form water-soluble complexes upon association with biological material wherein such biological material can include lipids or membrane proteins. Methods for producing, purifying, analyzing, and using the compositions and complexes are provided.

A thiosulfate polymer composition includes an electron-accepting photosensitizer component, either as a separate compound or as an attachment to the thiosulfate polymer. The thiosulfate polymer composition can be applied to various articles, or used to form a predetermined polymeric pattern after photothermal reaction to form crosslinked disulfide bonds, removing non-crosslinked polymer, and reaction with a disulfide-reactive material. Such thiosulfate polymer compositions can also be used to sequester metals in nanoparticulate form, and as a way for shaping human hair in hairdressing operations.

The resin composition of the present invention contains a maleimide compound (A) represented by the following formula (1); and a photo initiator (B) having an absorbance of 0.1 or more at a wavelength of 405 nm (h-line).

##STR00001##

In the formula (1), R.sub.1, R.sub.2, and R.sub.3 each independently represent an alkyl group or an alkoxy group which may have a hydrogen atom, a halogen atom, a hydroxyl group, or a substituent, R.sub.4 represents an alkylene group, an alkenylene group, an alkoxylene group, or an arylene group which may have a substituent, and R.sub.5 and R.sub.6 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 1 to 6 carbon atoms.

The resin composition of the present invention contains a maleimide compound (A) represented by the following formula (1); and a photo initiator (B) having an absorbance of 0.1 or more at a wavelength of 405 nm (h-line).

##STR00001##

In the formula (1), R.sub.1, R.sub.2, and R.sub.3 each independently represent an alkyl group or an alkoxy group which may have a hydrogen atom, a halogen atom, a hydroxyl group, or a substituent, R.sub.4 represents an alkylene group, an alkenylene group, an alkoxylene group, or an arylene group which may have a substituent, and R.sub.5 and R.sub.6 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 1 to 6 carbon atoms.

Amine-substituted copolymers that may include an amine-substituted pyrrolidine-2,5-dione moiety. Polyamic acids and polyimides, which may be formed by contacting an amine substituted copolymer with a dianhydride, or a dianhydride and a diamine. Articles, such as wires, having a surface on which a polyimide is disposed. Methods for forming polymers.

Amine-substituted copolymers that may include an amine-substituted pyrrolidine-2,5-dione moiety. Polyamic acids and polyimides, which may be formed by contacting an amine substituted copolymer with a dianhydride, or a dianhydride and a diamine. Articles, such as wires, having a surface on which a polyimide is disposed. Methods for forming polymers.

A benzoxazine resin composition is provided. The benzoxazine resin composition includes a benzoxazine resin that is a reaction product of an amine, a phenol, and an aldehyde. Either the amine is a diamine or the phenol is a bisphenol, and the benzoxazine resin has at least one nitrogen-containing crosslinking functional group or pyrocitric functional group. A method of preparing a benzoxazine resin composition is also provided. The method includes reacting an amine, a phenol, and an aldehyde at a temperature of above 60° C., for 1 h to 5 days to form a benzoxazine resin. The benzoxazine resin has at least one nitrogen-containing crosslinking functional group or pyrocitric functional group, and either the amine is a diamine or the phenol is a bisphenol. Also provided is a cured resin made from the benzoxazine resin composition.

An object of the present invention is to provide a novel photosensitive resin precursor that can be developed with an alkali and ring-closed even at low temperatures, and preferably has excellent thermal properties and excellent electric properties after curing, and also to provide a use application thereof. As means for achieving the object, disclosed are a bismaleimide compound comprising, in one molecule, two partial structures in each of which a carbon atom having a substituent represented by the following formula (A) (wherein Y represents a direct bond or a divalent linking group), and a carbon atom having a hydroxy group are directly bonded to each other, a polymer which is a self-polymer of the bismaleimide compound, and a benzoxazole which is an intramolecular dehydrated ring-closed product of the polymer.

##STR00001##

The resin composition of the present invention contains a maleimide compound (A) represented by the following formula (1); and a photo initiator (B) having an absorbance of 0.1 or more at a wavelength of 405 nm (h-line). ##STR00001## In the formula (1), R.sub.1, R.sub.2, and R.sub.3 each independently represent an alkyl group or an alkoxy group which may have a hydrogen atom, a halogen atom, a hydroxyl group, or a substituent, R.sub.4 represents an alkylene group, an alkenylene group, an alkoxylene group, or an arylene group which may have a substituent, and R.sub.5 and R.sub.6 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 1 to 6 carbon atoms.