Abstract: The invention pertains to the sealing of pistons for pressurizing, pumping and displacing aggressive liquids and organic solvents. The design includes the sealing head proper and its attachment to the piston. Owing to its shape and material it is made of, the sealing head ensures a variable sealing thrust proportional to the pressure acting on the piston, thus enhancing the useful life of the seal.

Abstract: There is disclosed a method of producing hydrogel tubes comprising partially hydrolyzing an acrylonitrile-containing polymer in an inorganic acidic solvent solution at temperature of about -10.degree. to 50.degree. C., extruding said hydrolyzed polymer solution through a circular nozzle into an aqueous coagulating bath, the same or similar coagulating bath simultaneously being fed through a central tube or pin of the nozzle.Preferably, the surface of the tube is made very slippery in wet condition, by treating it with chemical agents causing either a further hydrolysis or other reaction leading to carboxylic, sulfonic or sulfuric groups, or an esterification with polyols such as glycerol, glycols or polyvinyl alcohol, preferably with simultaneous sulfonation or sulfuration.

Abstract: This invention relates to a method for preparing globular, hydrophilic copolymers which have reticulated internal structures and are suitable for gas and gel chromatography. The method comprises polymerization by suspension polymerization methods of hydrophilic and hydrophilic monomers in aqueous medium in the presence of a component which prevents transfer of the hydrophilic monomer into the aqueous medium and the solubility of the aqueous medium in the monomeric phase.

Abstract: Polymers containing a reactive aromatic system in the side chain which consist of structural units of the general formula IV: ##STR1## where R.sup.1 is hydrogen or CH.sub.3,R.sup.2 is alkyl containing 1 to 6 carbon atoms,R.sup.3 is an acyl or sulfonic group,Ar is a bifunctional aromatic residue, andX=1 to 4.Said polymers being subject to further treatment consisting of acid hydrolysis and subsequent modification, e.g., with chloroacetic acid, formaldehyde or diazotizing and coupling with a suitable passive component.

Abstract: Method for determination of a straight line intersecting the axis of an optical radiation beam of a photoelectric levelling apparatus where the optical radiation beam transmits power from a stable radiation transmitter to a stable radiation receiver by screening the optical radiation beam by a screen and by evaluation of the signal detected by the radiation receiver by means of an evaluation circuit wherein the optical radiation beam is screened by screening means from at least two different sides of the optical radiation beam subsequently in mutually symmetrical positions of the screening means at a simultaneous indication from which side the optical radiation beam is screened, the evaluation circuit is evaluating the magnitude of the signal detected by the radiation receiver in case of screening from different sides of the optical radiation beam and by shifting the screening means transverse to the optical radiation beam the position is found.

Abstract: The invention relates to a method of manufacturing shaped articles from crystalline or quasi-crystalline acrylonitrile polymers and copolymers, said method consisting in cooling down a solution of said polymer or copolymer in a mixture containing from 50 to 99.5% by weight of a solvent and from 0.5 to 50% by weight of a precipitant to a temperature below the gelation point of the solution until the same gelatinizes, without changing its composition, to the desired shape, whereafter the solvent is removed from the shaped thermoreversible gel thus obtained at temperatures lower than the gelation point of the solution, preferably using a liquid precipitant of polyacrylonitrile miscible with the solvent. It is advantageous to remove the solvent at a temperature which is at least 10.degree. C. lower than the gelation temperature of the polymer solution used. The shaping can be carried out in any convenient way, e.g. using a stationary or rotating mold.

Abstract: A method of preparing cross-linked hydrogels in the form of shaped articles, insoluble in any solvent but swellable in water and in aqueous liquids is provided. The method comprises polymerizing acrylonitrile alone or with a minor amount up to 15% by weight of monoethylenically unsaturated monomers copolymerizable with acrylonitrile under conditions of radical polymerization in concentrated, i.e. 50 to 72% nitric acid in absence of any added chain-transfer and cross-linking agents, said monomer or monomers being used in concentrations making possible cross-linking by chain transfer onto the monomer, i.e. in concentrations ranging from 15 to 50%, preferably from 25 to 40% by weight, at temperatures ranging from 0.degree. to 50.degree. C., preferably from 5.degree. to 20.degree. C. The polymerization is carried out in a mold.

Abstract: The invention relates to specific sorbents based on hydrophylic polymeric gels, preferably of a macroporous character, which carry covalently bonded D-aminoacid or peptide which contain D-aminoacid units. The basic carrier prepared by copolymerization of hydroxyalkyl esters or hydroxyalkylamides of acrylic and methacrylic acid with crosslinking acrylate or methacrylate comonomers are modified by the reaction with diamines, aminoacids or dicarboxylic acids and the resulting carboxyterminal or aminoterminal groups are condensed with D-analogs of aminoacids or peptides. The peptide containing D-aminoacids can be also stepwise synthetized on the surface of the carrier. The specific sorbents are further used as insolubilized inhibitors in the affinity chromatography of proteolytic enzymes. They do not undergo an irreversible inactivation during repeated application and are suitable for technological purposes because of their mechanical and hydrolytical stability.

Abstract: A binding agent setting even at temperatures below +8.degree. C., or also at temperatures substantially lower, is manufactured on the basis of cement clinker of high specific surface area and contains as admixtures forming water, compounds based on lignosulfonates, and, if need be, also further admixtures for preparation of mortars and concretes, as is sand, rough compact and porous aggregates, regulating additives, wetting agents and dyes.

Abstract: Polymeric color pH indicators are prepared which are insoluble in the measured aqueous medium and show a certain range of color change. These polymeric indicators are the product of copolymerization of a hydrophilic comonomer, selected from esters, amides and N-substituted amides of acrylic and methacrylic acid, with 0.1- 30 wt.% of a comonomer. The comonomer forms the pH-indicating color center by a subsequent coupling with a suitable diazonium salt or a passive component. Vinylic monomers comprising an aromatic system in the molecule are suitable as the functional comonomers. The indicators are prepared by radical copolymerization of the comonomers either in a suspension or in a solution, followed by the subsequent coupling with a diazonium compound, or diazotizing and coupling with a passive component, to obtain the pH-indicating sites of polymer.

Abstract: The invention relates to a method for the preparation of polyamides with enhanced electric conductivity (specific resistance below 10.sup.9 .OMEGA..cm) by the anionic polymerization of lactams with 7 to 13 atoms in the ring using the usual basic polymerization initiators and accelerating activators. The polymerization is carried out in the presence of 2-20 wt. parts of plasticizers, e.g. N,N-dialkoxy or N,N-dialkylacrylamides or methacrylamides or their polymers, polyethyleneoxide, polyamides or lactams of higher concentration of amide groups than has the principal lactam, and 1-50 wt. parts of a very finely ground graphite and/or conductive black per 100 wt. parts of anhydrous principal lactam or mixture of lactams.The polymerization is performed in a mold to give directly the required article or in continuous reactors to various profiles or to form granulates.

Abstract: Method for testing of the embryotoxicity in the chicken embryo consists in reading the response of caudal morphogenetic system (CMS) of a chicken embryo to the presence of the tested substance in subgerminal fluid. The function of the caudal morphogenetic system is evaluated 24 hours after application by a simple quantitative parameter -- the length of a newly-formed part of the trunk. The substance, which interferes with some of the basic morphogenetic processes, slows down, stops or modifies the formation of the shape of the caudal part of trunk. Considering that the quantitative parameter is used as the index of the CMS function, each member of the experimental set presents information, not only the dead and malformed embryos as in classical methods. The second part of the test, i.e.

Abstract: The invention relates to preparation of synthetic macroporous ion-exchanaging materials by a ternary copolymerization of hydrophilic monomers containing non-ionogenous groups with monomers containing ionogenous groups and cross-linking monomers in an aqueous dispersion in the presence of inert components and suspension stabilizers. Hydroxyalkyl, oligoglycol and polyglycol esters and N-substituted or unsubstituted amides of acrylic and methacrylic acid are used as the hydrophilic monomers; compounds CH.sub.2 .dbd.C(R)COX, where R = H or CH.sub.3, X = --OR.sub.1 N(R.sub.2)R.sub.3, --OR.sub.1 SO.sub.3 H, --NHR.sub.1 N(R.sub.2)R.sub.3 or --HNR.sub.1 SO.sub.3 H, R.sub.1 = alkylene and R.sub.2 and R.sub.

Abstract: The invention relates to macroporous polymeric sorbents prepared by ternary copolymerization of polar monomers, namely hydroxyalkyl acrylates and methacrylates (hydroxyalkyl C.sub.1-6), in the amount of 1 - 70 wt.%, with 30 - 90 wt.% of nonpolar comonomers, namely alkyl acrylates and methacrylates (alkyl C.sub.1-18), and 20 - 80 wt.% of crosslinking agents, namely alkylene diacrylates and dimethacrylates (alkylene C.sub.1-6). The sorbents were prepared by the suspension copolymerization in the presence of inert organic solvents and surfactants in the single step without further chemical modification and their polarity was controlled in a broad region. They are especially suitable for gas-chromatographic separation of organic compounds, as hydrocarbons, alcohols, organic acids and nitrogen-containing heterocyclic compounds. Their preparation in one step is more simple and economical than modification of the polymeric matrix by polymeranalogous reactions which has been used for this purpose until present time.

Abstract: An acrylic polymer gel suitable for use as a carrier in the controlled synthesis of polypeptides is provided. The polymer comprises a diazotized terpolymer of the condensation product of a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates, a polyfunctional cross-linking monomer selected from the group consisting of alkylene diacrylates, alkylene dimethacrylates, polyacrylates and polymethacrylates of polyalcohols, alkylene bisacrylamides and divinylbenzene, and an aromatic ring-containing compound selected from the group consisting of aromatic acids and their anhydrides and chlorides, aromatic isocyanates, halogenophenylsilanes, and aromatic epoxy compounds. The condensate has its aromatic rings chlormethylated. The first monomer and the polyfunctional cross-linking monomer are copolymerized and the resultant copolymer is condensed with said compounds which contain an aromatic ring.

Abstract: The invention relates to polymers and copolymers of pivaloyloxyalkyl methacrylates which contain structural units of the general formula ##STR1## where R.sup.1 is (CH.sub.2).sub.n.sbsb.1 --O (n.sub.1 = 2 to 10) or (CH.sub.2 CH.sub.2 --O).sub.n.sbsb.2 (n.sub.2 = 1 to 4) and to the method of their preparation and modification. The polymerization and copolymerization can be initiated by free-radical initiators of the peroxy type or by anionic initiators, e.g., alkali metal alkoxides or butyllithium, and carried out in a solution, bulk or suspension process in the presence of a crosslinking agent or without it. Anionic polymerization may result in stereoregular polymers or may be used for preparation of block copolymers by the "living" polymer technique. The polymers and copolymers can be modified by the partial or toal conversion of the pivaloyloxyalkyl methacrylate units into hydroxyalkyl methacrylate units by selective hydrolysis, alcoholysis or other reaction.

Abstract: The invention relates to monomers of the general formula I with a reactive aromatic system based on p-phenylenediamine derivatives:Ch.sub.2 .dbd.cr.sup.1 --co--(o--ch.sub.2 --ch.sub.2).sub.x --NR.sup.2 --Ar--NH--R.sup.3 (I),where R.sup.1 is H or CH.sub.3, R.sup.2 is C.sub.1 -C.sub.6 alkyl, R.sup.3 is acyl, carboxylic group or sulfonic group. It further relates to methods for preparation of such monomers by the reaction of p-H.sub.2 NC.sub.6 H.sub.4 N(Et)CH.sub.2 CH.sub.2 OH or p-H.sub.2 NC.sub.6 H.sub.4 N(CH.sub.2 CH.sub.2 OH).sub.2 derivatives with blocked NH.sub.2 groups with chlorides of unsaturated organic acids or by nitrosation, reducing and above mentioned acylation of N-alkylaniline derivatives. It further relates to polymers prepared by polymerization or copolymerization of monomers I, which consist of structural units IV: ##STR1## where R.sup.1, R.sup.2, R.sup.3, Ar and x have the above given meaning, and to methods of their preparation.

Abstract: A process of manufacturing sodium lactamoaluminates by reacting an excess of a lactam in an aromatic hydrocarbon with at least one compound selected from sodium tetrahydridoaluminate, trisodium hexahydridoaluminate, sodium dihydrido-bis(2-methoxyethoxo)aluminate, and sodium tetraamidoaluminate.

Abstract: A method of preparing cross-linked hydrogels in the form of shaped articles, insoluble in any solvent but swellable in water and in aqueous liquids, is provided. The method comprises polymerizing acrylonitrile alone or with a minor amount up to 15% by weight of monoethylenically unsaturated monomers copolymerizable with acrylonitrile under conditions of radical polymerization in concentrated, i.e. 50 to 72%, nitric acid in the absence of any added chain-transfer and cross-linking agents, said monomer or monomers being used in concentrations making possible cross-linking by chain transfer onto the monomer, i.e. in concentrations ranging from 15 to 50%, preferably from 25 to 40% by weight, at temperatures ranging from 0.degree. to 50.degree. C, preferably from 5.degree. to 20.degree. C. The polymerization is carried out in a mold.

Abstract: The invention relates to a method for preparation of ion exchangers from hydrophilic anion-exchanging gels based on acrylate or methacrylate copolymers prepared by copolymerization of amino-group-containing monomers, as aminoalkyl acrylates and methacrylates, aminoalkylacrylamides and aminoalkylmethacrylamides or on gels prepared by chemical bonding of amine groups to the hydrophilic matrix of acrylate or methacrylate copolymers. The method consists in alkylation or hydroxyalkylation of amine groups by alkylating agents, as alkyl halogenides, alkyl p-toluenesulfonates, alkyl sulfates, epoxides, etc. Alkylation with alkyldiaze compounds was used for transformation of the undesired carboxylic groups of the ion exchangers. Another modification consists in the reaction of halogenated acrylate or methacrylate gels with polyamines or oligomeric polyethyleneimines.