Embodiments provide a method for controlled release of a cement additive for use in a wellbore. The method includes the steps of mixing an aramide capsule with a cement slurry to form an additive-containing slurry, and introducing the additive-containing slurry into the wellbore. The aramide capsule is formed by interfacial polymerization where an aramide polymer forms a semi-permeable membrane encapsulating the cement additive.

Embodiments provide a method for controlled release of a cement additive for use in a wellbore. The method includes the steps of mixing an aramide capsule with a cement slurry to form an additive-containing slurry, and introducing the additive-containing slurry into the wellbore. The aramide capsule is formed by interfacial polymerization where an aramide polymer forms a semi-permeable membrane encapsulating the cement additive.

The present invention relates to a mixture comprising at least one compound comprising an -hydroxy-carboxylic unit, -hydroxy-sulfonic acid unit or -carbonyl-carboxylic unit and at least one water-soluble organic carbonate. The mixture is useful as a hydration control agent in construction chemical compositions comprising an inorganic binder.

Embodiments provide a method of encapsulating a solid cement additive. The method includes the step of applying a base film-forming monomer to the solid cement additive. The method includes the step of forming a coating layer surrounding the solid cement additive. The coating layer includes the base film-forming monomer. The method includes the step of applying an overlay film-forming monomer to the coating layer surrounding the solid cement additive. The method includes the step of reacting the base film-forming monomer and the overlay film-forming monomer to produce a polymer shell. The solid cement additive includes solid particles useful in cementing applications. The polymer shell includes a crosslinked polymer. The polymer shell surrounds the solid cement additive. The polymer shell has a permeability to water allowing controlled release of the solid cement additive.

Embodiments provide a method of encapsulating a solid cement additive. The method includes the step of applying a base film-forming monomer to the solid cement additive. The method includes the step of forming a coating layer surrounding the solid cement additive. The coating layer includes the base film-forming monomer. The method includes the step of applying an overlay film-forming monomer to the coating layer surrounding the solid cement additive. The method includes the step of reacting the base film-forming monomer and the overlay film-forming monomer to produce a polymer shell. The solid cement additive includes solid particles useful in cementing applications. The polymer shell includes a crosslinked polymer. The polymer shell surrounds the solid cement additive. The polymer shell has a permeability to water allowing controlled release of the solid cement additive.

Provided is an amphoteric composite hydrogel, including: a polymer having a structure of formula I,

##STR00001##

wherein m, n, p and q are each an integer of 0 to 1000, m+n>100, p+q>100, R is

##STR00002##

R.sub.1 is H or an alkali metal element, and R.sub.2 is H or CH.sub.3; and a pozzolanic material incorporated into the structure of formula 1. Also provided are a cement mortar composition and a concrete composition each comprising the amphoteric composite hydrogel and a method of preparing the amphoteric composite hydrogel.

Provided is an amphoteric composite hydrogel, including: a polymer having a structure of formula I,

##STR00001##

wherein m, n, p and q are each an integer of 0 to 1000, m+n>100, p+q>100, R is

##STR00002##

R.sub.1 is H or an alkali metal element, and R.sub.2 is H or CH.sub.3; and a pozzolanic material incorporated into the structure of formula 1. Also provided are a cement mortar composition and a concrete composition each comprising the amphoteric composite hydrogel and a method of preparing the amphoteric composite hydrogel.

Embodiments provide a method for controlled release of a cement additive for use in a wellbore. The method includes the steps of mixing an aramide capsule with a cement slurry to form an additive-containing slurry, and introducing the additive-containing slurry into the wellbore. The aramide capsule is formed by interfacial polymerization where an aramide polymer forms a semi-permeable membrane encapsulating the cement additive.

Embodiments provide a method for controlled release of a cement additive for use in a wellbore. The method includes the steps of mixing an aramide capsule with a cement slurry to form an additive-containing slurry, and introducing the additive-containing slurry into the wellbore. The aramide capsule is formed by interfacial polymerization where an aramide polymer forms a semi-permeable membrane encapsulating the cement additive.

In general, the present invention is directed to the use of particular phosphorus containing compounds for making a gypsum board. The phosphorus containing compound may be a phosphite or a phosphate having a certain formula. In this regard, the present invention is directed to a slurry for making a gypsum board wherein the slurry includes such phosphorus containing compound. The present invention is also directed to a method of making a gypsum board from the slurry as well as a resulting gypsum board.