Abstract: Copolymers of aliphatic monoethylenically unsaturated dicarboxylic acids and unsaturated monomers have been formed by gradually and simultaneously adding monomers and initiator, in the presence of a metal salt activator, to a reaction vessel initially containing water at a temperature suitable for polymerization. These copolymers have consistent compositions and superior properties as antiscalants, dispersants and incrustation inhibitors.

Abstract: The acrylic copolymer of the present invention is an acrylic copolymer comprising recurring units derived from a (meth)acrylic ester compound and recurring units derived from a vinyl compound having --SO.sub.3 R (wherein R represents a hydrogen atom or a lower alkyl group) or having an acceptable salt thereof, wherein at least a part of ester groups of the (meth)acrylic ester compound is substituted by a group having recurring units derived from a (meth)acrylic ester. The present invention further provides a process for the preparation of the acrylic copolymer and use application of the acrylic copolymer utilizing its adhesion properties.

Abstract: The invention relates to a process for producing polyacrylic acids and copolymers of acrylic acid with up to 50 mol-% of comonomers. These compounds have a molecular weight of less than 100,000, measured at a pH-value of 8, and 10 to 60 mol-% are neutralized with calcium hydroxide. The invention also relates to the use of these products as grinding and dispersing aids for calcium carbonate.

Abstract: The invention relates to the stabilization of alkaline solutions of peroxide bleaching compounds using, as stabilizing agent, a water-soluble poly-.alpha.-hydroxyacrylic acid salt which in the sodium salt form has an average molecular weight Mw from 2000 to 10,000 and to the preparation of such a salt.

Abstract: Organic-inorganic hybrid polymers and a method of making them by reaction of organic monomers with organofunctional alkoxysilanes are disclosed.

Abstract: Polymers of itaconic acid are formed at high conversion by adding completely neutralized monomer solution and initiator solution to a vessel initially containing water at a temperature sufficient for polymerization. These polymers are biodegradable and are most useful as detergent additives, scale inhibitors and removers, sequesterants, yarn sizers, deflocculating agents, de-inking agents, suspending agents and dispersing agents.

Abstract: The use of a sulfoalkyl monomer in monovinylidene aromatic/(meth)acrylate/(meth)acrylic acid monomer latexes has been found to provide surprisingly good combinations of ion stability and moisture resistance. This is shown to be especially beneficial in paper coating and paint formulations. In examples, sulfopropyl methacrylate has proven especially beneficial in a styrene/n-butylacrylate/methacrylic acid latex for use in industrial-type, high strength coatings and formulations for coating offset printing paper.

Abstract: A process to efficiently utilize the chain transfer agent hypophosphorous acid or salts in the preparation of low molecular weight polycarboxylate polymers comprising employing in process neutralization of the carboxylic acid monomers.A low molecular weight polycarboxylate polymer containing phosphinate and phosphonate functional groups where less than 20% of the phosphorus is present in inorganic non polymeric compounds.

Abstract: A cable grade water proofing agent made of a cross-linked polymer produced by polymerizing a monomer mixture comprising at least one (meth)acrylic compound selected from the group consisting of (meth)acrylic acids and (meth)acrylic salts and a (meth)acrylamide in a molar ratio of said (meth)acrylic compound to said (meth)acrylamide in the range of from 1:9 to 5:5, said cross-linked polymer exhibiting a speed of absorption of not more than 8 minutes as expressed by the time required for the absorption of artificial seawater to reach 90% of the maximum, a capacity for absorption of said artificial seawater of not less than 8 times the own weight, and a gel viscosity in the range of from 0.6.times.10.sup.5 to 2.5.times.10.sup.5 dynes.multidot.s/cm.sup.3, and a composite waterproofing material carried on a substrate such as yarns and tape.

Abstract: Substantially alternating 1:1 copolymers of olefinically unsaturated sulfonate salts such as sodium methallylsulfonate and .alpha., .beta.-unsaturated aliphatic dicarboxylic acid anhydrides such as maleic anhydide are produced by free radical polymerization using a polar non-reactive organic solvent such as acetic acid. The copolymers and their derivatives are useful as water-soluble dispersants.

Abstract: A process for preparing a porous and water-absorbent resin which includes dispersing an aqueous solution containing at least one .alpha.,.beta.-unsaturated carboxylic acid monomer, its alkali metal salt or its ammonium salt in a hydrophobic organic solvent, and conducting a reversed phase suspension polymerization by using a water-soluble radical polymerization initiator, while distilling away the hydrophobic organic solvent together with water. A porous and water-absorbent resin having excellent absorbency and a remarkably improved rate of water absorption can be easily and efficiently obtained on an industrial scale.

Abstract: A method for the production of an acrylate by the neutralization reaction of acrylic acid and a basic substance, comprising sequentially (A) a step of supplying acrylic acid and said basic substance to water thereby subjecting them to a neutralization reaction while constantly retaining the neutralization ratio of acrylic acid within the neutralization reaction system in the range of 75 to 100 mol %, (B) a step of adjusting the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.1 to 110 mol % by supplying said basic substance to said neutralization reaction system, (C) a step of retaining the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.

Abstract: The present invention relates to elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The polymers are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic- substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: A process for producing a highly water absorptive polymer by polymerizing a water-soluble, ethylenically unsaturated monomer in a water-in-oil type of dispersion consisting of the dispersion phase of an aqueous monomer solution comprising the water-soluble, ethylenically unsaturated monomer, water, a water-soluble polymerization initiator and an optional water-soluble crosslinking agent and the continuous phase of an organic solvent containing a dispersant, characterized in that the aqueous monomer solution is added to the organic solvent at such a temperature as to form an oil-in-water type of dispersion, and the oil-in-water type of dispersion is then heated at least to a phase reversal temperature at which it is transformed into the water-in-oil type of dispersion.

Abstract: Reducing agents for oxidized developing agents and light sensitive elements containing the reducing agents wherein the reducing agents comprise a polymer having gallic acid or gallic acid derivative moieties.

Abstract: The invention relates to bidimensional organic membranes or diaphragms and to their preparation processes.These diaphragms have at least one monomolecular layer of organic molecules A, such as porphyrins, phthalocyanines and porphyrazines. In a layer, each molecule A is directly or indirectly bonded to n (n.gtoreq.3) identical molecules A by n bonds arranged symmetrically with respect to the center of the molecule A.Therefore there diaphragms have microscopic physical properties identical in at least two directions of the plane of the diaphragm. They can be used as conductive diaphragms.

Abstract: An improved wall decorating system is disclosed that utilizes a film comprising about 60-98% by weight ionomer resin that is a copolymer of ethylene and acrylic acid or methacrylic acid neutralized by a metal cation, the resin having a melt flow index greater than about 10 and about 2-40% by weight of a filler material, wherein the film has a thickness of between 0.050 and 0.127 mm. The wall decorating system also may include an improved adhesive comprising between about 60-100% by weight of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, and between about 0-40% by weight of a non-spherical polyacrylate adhesive.

Abstract: A new class of macromolecular monomers (hereinafter called "macromonomers") comprises the polymerized product of at least one of an ethenylarene and a conjugated diene monomer, the product having a terminal omega-alkenyl group of at least four carbon atoms. The novel macromonomer can be copolymerized with ethylene and alpha-olefin monomers to form graft copolymers having pendant side-chains. The graft copolymers are useful as coating and molding compositions. The macromonomers can be useful as coatings on chromatographic supports for analytical and preparative separation of chemical mixtures.

Abstract: There is provided a rubber/plastic insulated power cable or a joint of power cables which comprises a conductor or a conductor joint having an inner semiconductor layer and an insulation layer, and if necessary, an outer semiconductor layer, formed thereon in the order named, at least one of these layers being formed of a crosslinked structure of an olefin resin composition containing an olefin resin, an organic peroxide, and 2,4-diphenyl-4-methyl-1-pentene. The 2,4-diphenyl-4-methyl-1-pentene serves to inhibit "amber" of the olefin resin composition by the organic peroxide used and to increase the degree of crosslinking of crosslinked structure. Also, the olefin resin with a high melting point can be used as a base resin. Therefore, the resultant power cable and joint have highly improved AC breakdown strength, impulse breakdown strength at a high temperature and much less generation of electrical trees due to "amber", so that they are useful particularly high-voltage application.

Abstract: There is provided a process for producing a substantially water-insoluble, highly water-absorptive polymer which comprises subjecting an aqueous solution of a monomer comprising as a main component acrylic acid and/or its alkali metal salt to polymerization in the presence of a hypophosphorous acid compound.

Abstract: A conjugated diene sulfonation product represented by the formula (I): ##STR1## wherein R.sup.1 to R.sup.6, which may be the same or different, represent hydrogen atoms, alkyl groups having 1 to 8 carbon atoms, aryl groups having 6 to 20 carbon atoms or --SO.sub.3 X groups (X represents a hydrogen atom, a metal atom, an ammonium group or a quaternary ammonium group), at least one of said R.sup.1 to R.sup.6 being the --SO.sub.3 X group, a polymer of the conjugated diene sulfonation product or a copolymer of the conjugated diene sulfonation product with a monomer copolymerizable therewith. The sulfonation product, the polymer and the copolymer are useful as a dispersing agent for preparing a solid fuel dispersion, a cement dispersion, a dye and/or pigment dispersion or a metal oxide dispersion or as a water-treating agent, a fiber-treating agent, a plating bath additive and an excavation-muddy water-viscosity-adjusting agent.

Abstract: A water-soluble complexing agent of metallic cations having a high complexing power and a high threshhold effect, constituted from acrylic copolymers, characterized by the fact that said agent is formed by terpolymers comprising acrylic and methacrylic and itaconic units of the general formula: ##STR1## in which the indices, expressed in percent by weight have at least a value of 10 for x and y, and a value of 5 for z.

Abstract: Ionic copolymers exhibiting uniform, gel-free solution viscosity and a controllable melt viscosity and hot melt tension are prepared by copolymerizing in an oil phase a nonionic monomer such as styrene or an alkylacrylate with an ionic monomer such as zinc dodecyl maleate or didodecyldimethylammonium p-styrene sulfonate.

Abstract: This invention relates to electrically conductive and non-conductive forms of poly(heterocyclic vinylenes) and to solutions of same. Another aspect of this invention relates to novel precursor polymers which can be converted into the poly(heterocyclic vinylenes) of this invention.

Abstract: Glycerol derivatives of general formula (I) ##STR1## in which R=allyl, methylallyl, acryloyl or methacryloyl, R.sub.1 =R.sub.2 =glyoxyloyl, R.sub.1, R.sub.2 =H, glyoxyloyl; their preparation process, their use as cross-linking agnets and cross-linking or cross-linkable compositions containing them. These compounds are useful as crosslinking agents for woven and non-woven fibrous mats and textiles.

Abstract: Polymers of olefin monomers and a substantially uniform concentration of carboxyl, hydroxyl, thio, amino, carbonyl and imino functional group-containing monomers. Polymers of olefin monomers and carboxyl, hydroxyl, thio, amino, carbonyl and imino functional group-containing monomers substantially devoid of halogen. Method for preparing polymers by reacting carboxyl, hydroxyl, thio, amino, carbonyl and imino functional group-containing monomers with non-halogenated organometallic compounds to form masked, functional group-containing monomers and polymerizing polymer chain monomers with the masked, functional group-containing monomers to produce a polymer chain. Method for forming masked, functional group-containing monomers by reacting carboxyl, hydroxyl, thio, amino, carbonyl and imino functional group-containing monomers with non-halogenated organometallic compounds. Masked, carboxyl, hydroxyl, thio, amino, carbonyl and imino functional group-containing monomers.

Abstract: Certain novel cationic polyelectrolytes are useful as components of formulations for treating keratinaceous and proteinaceous substrates.

Abstract: Certain ethylenically unsaturated polymerizable monomers having a reactive carboxy group are useful for preparing homo- and copolymers for a variety of uses, including diagnostic assays. The polymers can be supplied as latex particles in aqueous compositions. The monomers are represented by the structure: ##STR1## wherein: R is hydrogen, halo or alkyl or 1 to 3 carbon atoms,M is hydrogen, an alkali metal ion or an ammonium ion, andL is a linking group having from 8 to 50 atoms in its linking chain, and comprises two or more divalent hydrocarbon groups connected or terminated with one or more nitrogen, oxygen or sulfur atoms, or with one or more groups containing such atoms in the linking chain, provided L has at least one arylene which is not directly connected to the terminal ##STR2## and further provided that none of the hydrocarbon groups has non-aromatic unsaturation.

Abstract: Radiation-sensitive polymers suitable for use in positive- and negative-working recording elements contain not only acid-labile groups but also onium salt groups having nonnucleophilic counterions in one and the same molecule.

Abstract: The present invention provides crosslinked ampholytic copolymers that are highly absorbent to aqueous electrolyte solutions.

Abstract: A water soluble terpolymer useful in controlling deposition of scale in aqueous systems comprised of monomeric repeat units (g), (h) and (i) wherein repeat unit (g) comprises the structure ##STR1## wherein E is the repeat unit obtained after polymerization of an .alpha.,.beta. ethylenically unsaturated compound, wherein repeat unit (h) comprises the structure ##STR2## wherein R.sub.1 and R.sub.2 are the same or different and denote H, methyl or ethyl and M is a water soluble cation or H, andwherein repeat unit (i) comprises the structure ##STR3## wherein R.sub.3 is H or a lower alkyl (C.sub.1 -C.sub.3), R.sub.4 is a hydroxy substituted alkyl or alkylene group having from 1 to about 6 carbon atoms or a non-substituted alkyl or alkylene group having from 1 to about 6 carbon atoms, X is an anionic radical, Z is H, hydrogen atoms or a water soluble cation or cations which together counterbalance the valance of X and a is 0 or 1.

Abstract: Alkenylaminomethylenephosphonic acids of the formula ##STR1## in which R.sub.1 is hydrogen, C.sub.4 -C.sub.10 -alkyl, phenyl, naphthyl, methylphenyl, hydroxyphenyl, methoxyphenyl, methylnaphthyl, hydroxynaphthyl or methoxynaphthyl,R.sub.2 is hydrogen,R.sub.3, R.sub.4, R.sub.5 are hydrogen or methyl,R.sub.5 is hydrogen, C.sub.1 -C.sub.4 -alkyl or phenyl, andM is hydrogen or a cation,and copolymers comprising 0.1-99.9% by weight, preferably 1-50% by weight, of one or more monomers of the formula I, in which R.sub.2 is hydrogen or a group of the formula--CH.sub.2 PO.sub.3 M.sub.2, and 99.9-0.1% by weight, preferably 99-50% by weight, of one or more monomers of the formula IIR.sub.1 'R.sub.2 'C.dbd.CR.sub.3 'X (II)in whichR.sub.1 ' is hydrogen or a group of the formula --COOM,R.sub.2 ' is hydrogen, phenyl or a group of the formula --COOM,R.sub.3 ' is hydrogen, methyl or a group of the formula --COOM or --CH.sub.2 COOM,X is a group of the formula --COOM orR.sub.2 ' and R.sub.3 ' together are a C.sub.

Abstract: The present invention relates to elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The polymers are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic-substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: A plastic optical fiber comprising a core and a clad, said core being formed by an amorphous and optically transparent polymer and said clad being formed by a polymer having a refractive index lower than that of the core by at least 0.3%, at least one of the core and the clad being formed by an amorphous and optically transparent polymer containing metal elements and halogen atoms, is low in light loss and excellent in heat resistance.

Abstract: The present invention provides crosslinked ampholytic ion pair (2-methacryloyloxyethyldiethylammonium cation (MEDEA)/sulfonate anion) copolymers that are highly absorbent to aqueous electrolyte solutions.

Abstract: A new class of macromolecular monomers (hereinafter called "macromonomers") comprises the polymerized product of at least one of an ethenylarene and a conjugated diene monomer, the product having a terminal omega-alkenyl group of at least four carbon atomes. The novel macromonomer can be copolymerized with ethylene and alpha-olefin monomers to form graft copolymers having pendant side-chains. The graft copolymers are useful as coating and molding compositions. The macromonomers can be useful as coatings on chromatographic supports for analytical and preparative separation of chemical mixtures.

Abstract: Water-soluble polymers having K values of from 5 to 100 (determined on the Na salt of the polymers according to H. Fikentscher in aqueous solution at 25.degree. C., a pH of 7 and a concentration of 1% by weight of the Na salt of the polymer) are prepared by polymerizing a monomer mixture of(a) monethylenically unsaturated C.sub.3 -C.sub.8 -monocarboxylic acids and(b) more than 20-100 mol % of monomers which have two or more ethylenically unsaturated double bonds linked via one or more ester or amide functions and which contain one or more --CO--OX groups, where X is one hydrogen equivalent, one alkali metal equivalent or one alkaline earth metal equivalent or an ammonium group,in aqueous solution in the presence of a polymerization initiator, and the polymers are used in amounts of from 0.5 to 25% by weight in detergents and cleaners.

Abstract: Copolymers based on ethylenically unsaturated monomers and containing urethane groups, processes for their preparation and their use.Copolymers prepared by free-radical-initiated copolymerization of ethylenically unsaturated copolymerizable monomers, in which the copolymers are preferably synthesized froma) 25 to 85% by weight of ethylenically unsaturated hydrophobic monomers, andb) 1 to 50% by weight of ethylenically unsaturated monomers capable of salt formation, andc) 0.

Abstract: This invention relates to copolymers containing as copolymerized monomer units aliphatic monoethylenically unsaturated dicarboxylic acids such as maleic acid, monoethylenically unsaturated monocarboxylic acids such as acrylic acid and carboxyl-free monoethylenically unsaturated monomers such as alkyl esters of acrylic acid. This invention particularly relates to the use of low levels of copper ions in an aqueous polymerization process to promote copolymerization of the above-mentioned monomers at high conversion while maintaining and improving molecular weight control. These copolymers are useful primarily as antiscalants, dispersants, hard surface cleaners, detergent builders and incrustation inhibitors.

Abstract: A radiation-sensitive polymer is capable of resistance to the dry etching when it is applied to form very fine patterns in VLSIs and other semiconductor devices, wherein the polymer is a radiation-sensitive polymer that contains at least one unit represented by the general formula (I): ##STR1## (where X is an alkyl group, a halogen atom or a halogenated alkyl group; R.sup.1 is an alkyl group, an alkoxy or an aryl group; R.sup.2 is carbon monoxide; M is Si, Ge, Sn, Ti, Mo or W; k is a number defined by the valence of (M minus 1); and l is zero or a positive integer), and which optionally contains at least one unit represented by the general formula (II): ##STR2## (where Y is an alkyl group, a halogen atom or a halogenated alkyl group; R.sup.3 is an alkyl group or an aryl group) and/or at least one unit represented by the general formula (III):--SO.sub.2 --R.sup.4 (III)(where R.sup.4 is a divalent alkyl or aryl group).

Abstract: Novel water-soluble linear copolymers of N-vinylamides with monomeric addition products of amines, amino acids, amino groups containing aromatic sulfonic acids, amino alcohols of maleic anhydride as well as maleic esters of polyoxyalkyleneglycols or their monoethers. There is also described the process for the preparation of these copolymers. The copolymers are useful as fluidizers in water containing solid matter suspensions.

Abstract: A non-polluting dispersing agent for drilling fluids based on soft water or salt water.A dispersing agent for aqueous drilling fluids, optionally saline, belonging to the group of polymers and/or copolymers containing acid functions which is characterized in that, to ensure that these fluids retain their rheological characteristics, even under the extreme temperature and pressure conditions prevailing in deep bore holes, said dispersing agent is a salt of said polymers and/or copolymers of which the salifying cation corresponds to a metal having a Pauling electronegativity at least equal to 0.95 and preferably greater than 1.

Abstract: New homopolymers formed by malonic (meth)acrylamide monomer units according to the following formula: ##STR1## wherein R is H or CH.sub.3 ; X is H or an alkaline metal or NH.sub.4.sup.+ ; and copolymers formed by (meth)acrylamide monomer units (I) and monomer units (II).

Abstract: This invention describes novel hydrophobically associating terpolymers containing sulfonate functionality which are useful as aqueous fluid rheology or flow modifiers. These high molecular weight water soluble polymers contain both water soluble and water insoluble monomers. The water soluble monomers are acrylamide (AM) and a salt of an ethylenically unsaturated sulfonic acid (S) and the water insoluble monomer is a higher alkyl acrylamide (R). These polymers are referred to as SRAM. The process for their preparation relies on solubilizing the water insoluble monomer into an aqueous micellar solution containing one or more surfactants and the water soluble monomers. The surfactants are specifically selected to enable homogenous dispersion of the hydrophobic monomer(s) in the presence of anionic sulfonate containing monomers.

Abstract: There is provided a process for producing a highly water absorptive polymer, which comprises making up a mixture (A) comprising an aqueous solution of (a) a partially neutralized product of acrylic acid with 20% or more of carboxylic groups being neutralized to an alkali metal salt or ammonium salt, (b) a crosslinking agent having two or more copolymerizable vinyl groups in one molecule, (c) a basic vinyl monomer in a quantity of 20 mol % or less based on said partially neutralized product of acrylic acid, (d) a nonionic surfactant with HLB of 7 or more and (e) an oxidative radical polymerization initiator, said mixture (A) being maintained at a temperature of 50.degree. C. or lower, and a mixture (B) comprising an amine or a reducing agent dissolved in water or in said mixture (A) from which at least the component (e) is removed, and mixing both the mixtures to cause polymerization.

Abstract: This invention provides an improved process for producing a superabsorbent polymer with reduced residual monomer content which comprises partially drying a crosslinked, partially neutralized polymer gel, then raising the temperature of the gel using microwaves or RF radiation in the absence of circulating air and thereafter completing the drying.

Abstract: Disclosed are stabilizer compositions comprising specific mixed partial salts of a lower alkyl vinyl ether-maleic acid copolymer wherein said partial salts contain as the cationic salt function:(a) from about 10% to about 65% zinc or strontium cations; and(b) from about 10% to about 75% calcium cationsof the total initial carboxyl groups reacted. Also disclosed are denture stabilizing compositions comprising these mixed partial salts, as well as denture stabilizing compositions comprising a safe and adhesively effective amount of two or more denture adhesive components wherein one of said denture adhesive components is the mixed partial salt(s) of the present invention.

Abstract: A hydrophilic polymer having the water absorption capacity thereof 1 to 30 times to its own weight by a process of manufacture which comprises preparing a monomer component comprising (a) 2 to 25 mol % of a hydroxyl group-containing alpha,beta-ethylenically unsaturated monomer, (b) 5 to 30 mol % of a carboxyl group-containing alpha,beta-ethylenically unsaturated monomer, and (c) 93 to 45 mol % of a carboxylate group-containing alpha,beta-ethylenically unsaturated monomer, providing that the total of (b) and (c) is in the range of 98 to 75 mol %, radically polymerizing said monomer component, and heat-treating the resultant polymer thereby causing the hydroxyl group and carboxyl group possessed by the polymer to react with each other and form a crosslinked structure, a method for the production thereof, and uses found therefor including a cation sequestrating resin, a coolant and a coating material.

Abstract: The present invention relates to compounds of the general formula I ##STR1## in which R.sup.1, R.sup.1', R.sup.2, A and n are as defined in the description, a process for their preparation, their use and also hydrogels prepared using them.

Abstract: Alkenylphosphonic and -phosphinic acid esters of 1,1,1-tris(hydroxymethyl)alkanes and of 2,2-bis-hydroxymethyl-1,3-propanediol are useful as cross-linking agents in polymeric hydrogels.