A graft copolymer and a preparation method and use thereof. The method for preparing a graft copolymer includes: dissolving an N-ethyl-2-pyrrolidinone-substituted flavan-3-ol (EPSF) and a starch in a polar organic solvent, to obtain a raw material solution; and mixing the raw material solution with ascorbic acid and hydrogen peroxide to obtain a mixture, and subjecting the mixture to a grafting reaction, to obtain the graft copolymer. The graft copolymer has a structural formula represented by formula I or formula II, ##STR00001##

A graft copolymer and a preparation method and use thereof. The method for preparing a graft copolymer includes: dissolving an N-ethyl-2-pyrrolidinone-substituted flavan-3-ol (EPSF) and a starch in a polar organic solvent, to obtain a raw material solution; and mixing the raw material solution with ascorbic acid and hydrogen peroxide to obtain a mixture, and subjecting the mixture to a grafting reaction, to obtain the graft copolymer. The graft copolymer has a structural formula represented by formula I or formula II, ##STR00001##

The present disclosure relates more particularly to calcium sulfate-based slurries useful, for example, in making gypsum boards for building construction, as well as methods for using them, e.g., to make gypsum boards, in one aspect, the present disclosure provides a calcium sulfate slurry composition comprising calcium sulfate present substantially in the form of one or more hydrates, the calcium sulfate being present in an amount in the range of 70-99.8 wt % on a dry basis, calculated as stucco; and a cationic starch present in an amount of 0.10-10 wt % of the amount of calcium sulfate as stucco on a dry basis, the cationic starch being substituted with amine and/or ammonium groups and having a % N value in the range of 0.10 wt. % to 2 wt %, and an RVA viscosity value of at least 100 cP at 65 C. and 16 wt %; and water, in an amount sufficient to form a slurry. The disclosure also provides gypsum-based materials useful as building materials, e.g., for use as building boards in construction of walls and ceilings of buildings.

The present invention provides a method for producing a water-soluble polymer with high production efficiency, and a method for producing a water-absorbing resin having excellent water absorption performance. The present invention relates to a method for producing a water-soluble polymer, comprising: (a1) reducing the molecular weight of a starch to obtain a partially degraded starch; and (a2) introducing an ionic functional group into the partially degraded starch obtained in the step (a1).

The present invention provides a method for producing a water-soluble polymer with high production efficiency, and a method for producing a water-absorbing resin having excellent water absorption performance. The present invention relates to a method for producing a water-soluble polymer, comprising: (a1) reducing the molecular weight of a starch to obtain a partially degraded starch; and (a2) introducing an ionic functional group into the partially degraded starch obtained in the step (a1).

Cationic and silicon substituents are introduced into polysaccharides thereby producing modified polysaccharides cationically substituted by quaternary ammonium groups and having a charge density of about 0.1 to about 2.5 meq/g, and further substituted by siliconate groups such that the modified polysaccharide has a silicon content of about 300 to about 5000 ppm. The modified polysaccharides have application in industrial, home care and personal care surface modifying formulations.

Cationic and silicon substituents are introduced into polysaccharides thereby producing modified polysaccharides cationically substituted by quaternary ammonium groups and having a charge density of about 0.1 to about 2.5 meq/g, and further substituted by siliconate groups such that the modified polysaccharide has a silicon content of about 300 to about 5000 ppm. The modified polysaccharides have application in industrial, home care and personal care surface modifying formulations.

The present invention provides a hydroxypropylated granular starch with a degree of molar substitution of hydroxypropyl groups (MS) of above 0.25 and a reduced content of volatile organic compounds (VOC), namely a propylene glycol content of below 2 wt.-% of the starch, and a process for the preparation of said hydroxypropylated granular starch. The present invention further relates to a hydroxypropylated starch with a degree of molar substitution of hydroxypropyl groups (MS) in the range of 0.3 to 0.5 and a propylene glycol content of below 2 wt.-% of the starch, and to a construction material composition or cementitious and/or dispersion-modified construction adhesive comprising said hydroxypropylated starch.

The present invention provides a hydroxypropylated granular starch with a degree of molar substitution of hydroxypropyl groups (MS) of above 0.25 and a reduced content of volatile organic compounds (VOC), namely a propylene glycol content of below 2 wt.-% of the starch, and a process for the preparation of said hydroxypropylated granular starch. The present invention further relates to a hydroxypropylated starch with a degree of molar substitution of hydroxypropyl groups (MS) in the range of 0.3 to 0.5 and a propylene glycol content of below 2 wt.-% of the starch, and to a construction material composition or cementitious and/or dispersion-modified construction adhesive comprising said hydroxypropylated starch.

A method for the synthesis of alkyl -carboxy(hydroxyethyl) polysaccharides is described. The method includes methylating or ethylating a polysaccharide or providing a methylated or ethylated polysaccharide, hydroxyethylating the methylated or ethylated polysaccharide, and oxidizing the hydroxyethylated polysaccharide to form the -carboxy(hydroxyethyl) polysaccharide. A method for the synthesis of oxidized polysaccharides is also described. The method includes hydroxypropylating a polysaccharide and oxidizing the hydroxypropylated polysaccharides. A method for the production of a solid capable of forming a hydrogel is also described. The method includes combining a first solution comprising an oxidized oligo(hydroxypropyl) polysaccharide bearing one or more ketone groups with a second solution comprising an amine substituted polysaccharide to form a third solution, and removing solvent from the third solution to form the solid, or adding an additional solvent to the third solution to precipitate the solid. Novel polysaccharides and hydrogels prepared according to these methods are also described.