Abstract: A coating composition includes a UV curable film forming resin; a thixotropic and/or pseudoplastic anti-settling agent selected from at least one of an amine salt of a synthetic wax, a microcrystalline cellulose compound (MCC), a urea urethane, or a urethane enzymatically modified starch; a mar/scratch resistant additive selected from at least one of a mineral abrasive, glass particles, and ceramic particles; and water.

Abstract: Embodiments in accordance with the present invention are directed to polymer compositions that are useful for forming temporary bonding layers that serve to releasably join a first substrate to a second substrate as well as methods of both forming such a temporary bond and methods of debonding such substrates. Some such polymer compositions encompass a casting solvent, a photoacid generator and optionally a sensitizer and/or an adhesion promoter.

Abstract: A dental adhesive composition comprising (i) at least one non-acidic polymerizable monomer having at least one ethylenically unsaturated group, (ii) optionally one or more acidic compounds, (iii) at least one photoinitiator, (iv) at least one solvent, and (v) about 0-40% by weight of one or more fillers; wherein the weight ratio of non-acidic polymerizable monomers/acidic compounds in the adhesive composition is more than about 4.5; the viscosity of the adhesive composition is less than about 350 centipoise (cP) at 25° C.; and the adhesive composition excluding solvent and filler has an acid number of less than about 0.75 mmol NaOH/g. The dental adhesive composition is used with a dental primer composition, which may be provided together in a kit.

Abstract: A process for preparing a pressure sensitive adhesive using a modified planetary roller extruder is described. The process in accordance with one aspect of the invention is a continuous process that includes introducing primary raw materials comprising a non-thermoplastic elastomer into a planetary roller extruder, introducing a heat-activatable crosslinker into the planetary roller extruder for mixing with the primary raw materials, and compounding the primary raw materials and the heat activatable crosslinker to form an adhesive composition while maintaining the temperature of the adhesive composition between about 25° C. and about 100° C. The non-thermoplastic elastomer is masticated during compounding and at least some of the heat-activatable crosslinker remains generally unactivated and is available for later activation.

Abstract: Disclosed are a black photosensitive resin composition that includes (A) an organic binder resin, (B) a reactive unsaturated compound, (C) a photopolymerization initiator, (D) a black pigment including carbon black and a silver-tin-containing alloy, and (E) a solvent, and a light blocking layer using the same.

Abstract: The present invention relates to methods for making oxidation resistant medical devices that comprise polymeric materials, for example, ultra-high molecular weight polyethylene (UHMWPE). The invention also provides methods of making antioxidant-doped medical implants, for example, doping of medical devices containing cross-linked UHMWPE with vitamin E by diffusion and materials used therein.

Abstract: The present invention relates to methods for making oxidation resistant homogenized polymeric materials and medical implants that comprise polymeric materials, for example, ultra-high molecular weight polyethylene (UHMWPE). The invention also provides methods of making antioxidant-doped medical implants, for example, doping of medical devices containing cross-linked UHMWPE with vitamin E by diffusion and annealing the antioxidant doped UHMWPE in a super critical fluid, and materials used therein.

Abstract: The present invention relates to a homogenous liquid blend comprising a photoinitiator and an alkoxylate surfactant for incorporation into aqueous based and solvent based radiation curable systems. In particular the invention relates to a homogenous liquid blend which is liquid at room temperature comprising at least 30% by weight with regard to the whole blend of a solid photoinitiator of the radical type and 1-70% by weight of at least one alkoxylated liquid surface active agent and optionally an organic diluent.

Abstract: The invention provides methods for inducing reversible chain cleavage of polymer chains in a crosslinked polymeric material. Reversible cleavage of the polymer backbone is capable of relieving stress in the polymeric material as the bonds reform in a less stressed state. The invention also provides methods for making polymeric materials capable of reversible chain cleavage, materials made by the methods of the invention, and linear monomers containing reversible chain cleavage groups which are useful in the materials and methods of the invention.

Abstract: The present invention is one capable of collecting the metal dissolving in a solution, wherein graft chains of a glycidylalkyl(meth)acrylate represented by the following general formula (1) are formed in the polymer substrate and the graft chain has an amino group or a sulfonic acid group: (In the general formula (1), R1 represents a hydrogen atom or a methyl group; R2 represents a linear or branched alkylene group having from 4 to 10 carbon atoms.

Abstract: An object of the present invention is to provide a novel cationic photopolymerization initiator that efficiently absorbs light and generates protons. As a means of achieving the object above, a preferred cationic photopolymerization initiator of the present invention includes an initiator comprising a bismuthonium salt represented by the following general formula (II): Wherein R11, R12, and R13 may be the same or different and are each an optionally substituted monocyclic aryl group or an optionally substituted monocyclic heteroaryl group, R14 is an optionally substituted fused polycyclic aromatic group or an optionally substituted fused polycyclic heterocyclic group, and X? is an anion associated with a cation.

Abstract: An antioxidant combined with UHMWPE prior to subjecting the UHMWPE to crosslinking irradiation. In one exemplary embodiment, the antioxidant is tocopherol. After the antioxidant is combined with the UHMWPE, the resulting blend may be formed into slabs, bar stock, and/or incorporated into a substrate, such as a metal, for example. The resulting product may then be subjected to crosslinking irradiation. In one exemplary embodiment, the UHMWPE blend is preheated prior to subjecting the same to crosslinking irradiation. Once irradiated, the UHMWPE blended product may be machined, packaged, and sterilized in accordance with conventional techniques.

Abstract: An antioxidant combined with UHMWPE prior to subjecting the UHMWPE to crosslinking irradiation. In one exemplary embodiment, the antioxidant is tocopherol. After the antioxidant is combined with the UHMWPE, the resulting blend may be formed into slabs, bar stock, and/or incorporated into a substrate, such as a metal, for example. The resulting product may then be subjected to crosslinking irradiation. In one exemplary embodiment, the UHMWPE blend is preheated prior to subjecting the same to crosslinking irradiation. Once irradiated, the UHMWPE blended product may be machined, packaged, and sterilized in accordance with conventional techniques.

Abstract: A method for removing vinyl monomers from a gas stream comprises steps of: irradiating a photoactive-inorganic medium by a light emitting unit to activate the photoactive-inorganic medium; and pumping a gas stream including vinyl monomers to contact with the activated photoactive-inorganic medium to make the vinyl monomers in the gas stream to polymerize on the photoactive-inorganic medium to jointly form a polymeric nano-composite.

Abstract: A process for preparing a pressure sensitive adhesive using a modified planetary roller extruder is described. The process in accordance with one aspect of the invention includes introducing primary raw materials including a non-thermoplastic elastomer into a feeding section of the modified planetary roller extruder, conveying the raw materials from the feeding section to a compounding section of the modified planetary roller extruder, continuously mixing the primary raw materials in the compounding section to produce a homogeneous adhesive composition. The adhesive composition may be applied to a web-form material. The compounding section of the modified planetary roller extruder includes a main spindle surrounded by and intermeshed with a plurality of planetary spindles at least one of which is a double transversal mixing spindle having a plurality of back-cut helical flights.

Abstract: The present invention provides an irradiated crosslinked polyethylene containing reduced free radicals, preferably containing substantially no residual free radical. Disclosed is a process of making irradiated crosslinked polyethylene by irradiating the polyethylene in contact with a sensitizing environment at an elevated temperature that is below the melting point, in order to reduce the concentration of residual free radicals to an undetectable level. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein.

Abstract: A radiation curable solid ink composition comprising at least one curable wax that is curable by free radical polymerization; at least one monomer, oligomer, or prepolymer; at least one non-curable wax; at least one free-radical photoinitiator or photoinitiating moiety; and a colorant; wherein the components form a curable ink composition that is a solid at a first temperature of from about 20 to about 25° C.; and wherein the components form a liquid composition at a second temperature of greater than about 40° C.

Abstract: The invention provides methods for inducing reversible chain cleavage of polymer chains in a crosslinked polymeric material. Reversible cleavage of the polymer backbone is capable of relieving stress in the polymeric material as the bonds reform in a less stressed state. The invention also provides methods for making polymeric materials capable of reversible chain cleavage, materials made by the methods of the invention, and linear monomers containing reversible chain cleavage groups which are useful in the materials and methods of the invention.

Abstract: Polyolefin waxes bearing (meth)acrylate groups, process for preparing them and their use.

Abstract: There is provided a method for preparing a plumbing manifold for use in a water system in which the manifold after molding is subjected to cross-linking high energy radiation. The manifold is made by polyethylene or a metallocene polyethylene.

Abstract: Highly crystalline, oxidation resistant crosslinked polymeric materials such as crosslinked ultrahigh molecular weight polyethylenes having high wear resistance, enhanced stiffness, enhanced tensile strength, a high level of fatigue and crack propagation resistance, and enhanced creep resistance can be manufactured by the new methods described herein.

Abstract: An article suitable for use as an insulating or coating material comprises a radiation-crosslinked composition comprising a polyethylene, a polypropylene and optionally an ethylene-propylene elastomer. The polyethylene component is selected from high density polyethylene (HDPE), medium density polyethylene (MDPE) and linear medium density polyethylene (LMDPE) and the polypropylene component is either a homopolymer or copolymer. The composition is predominantly based on the polyethylene component and contains the polyethylene component in an amount of at least 50 percent by weight. The article is radiation-crosslinked to a sufficient degree that it possesses thermoset properties, such that when the article is heated to a temperature above the crystalline melting point of the polypropylene homopolymer or copolymer, it is softened but does not become liquid.

Abstract: The present invention provides an irradiated crosslinked polyethylene containing reduced free radicals, preferably containing substantially no residual free radical. Disclosed is a process of making irradiated crosslinked polyethylene by irradiating the polyethylene in contact with a sensitizing environment at an elevated temperature that is below the melting point, in order to reduce the concentration of residual free radicals to an undetectable level. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein.

Abstract: Fluoropolymers are made by admixing tetrafluoroethylene, hexfluoropropylene, and vinylidene fluoride; reacting the reaction admixture to generate a set of fluoropolymeric oligomers; irradiating the fluoropolymeric oligomeric precursor admixture (preferably with electron beam radiation) to form free radical sites on individual fluoropolymeric oligomers of the set and generate thereby a set of free radical oligomer derivatives in the fluoropolymeric oligomeric precursor admixture; and reacting the fluoropolymeric oligomeric precursor admixture to derive the fluoropolymer compound from the free radical oligomer derivatives. In a second approach, fluoropolymers are made by admixing tetrafluoroethylene, hexfluoropropylene, and vinylidene fluoride and irradiating the admixture.

Abstract: A method of making a crosslinked polymer is provided as well as the polymer so made, the method comprising the steps of: providing a highly fluorinated fluoropolymer, typically a perfluorinated fluoropolymer, comprising pendent groups which include a group according to the formula —SO2X, where X is F, Cl, Br, OH, or —O?M+, where M+ is a monovalent cation, and exposing said fluoropolymer to electron beam radiation so as to result in the formation of crosslinks. Typically, the method according to the present invention additionally comprises the step of: forming said fluoropolymer into a membrane, typically having a thickness of 90 microns or less, more typically 60 microns or less, and most typically 30 microns or less.

Abstract: The present invention provides an irradiated crosslinked polyethylene containing reduced free radicals, preferably containing substantially no residual free radical. Disclosed is a process of making irradiated crosslinked polyethylene by irradiating the polyethylene in contact with a sensitizing environment at an elevated temperature that is below the melting point, in order to reduce the concentration of residual free radicals to an undetectable level. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein.

Abstract: An antioxidant combined with UHMWPE prior to subjecting the UHMWPE to crosslinking irradiation. In one exemplary embodiment, the antioxidant is tocopherol. After the antioxidant is combined with the UHMWPE, the resulting blend may be formed into slabs, bar stock, and/or incorporated into a substrate, such as a metal, for example. The resulting product may then be subjected to crosslinking irradiation. In one exemplary embodiment, the UHMWPE blend is preheated prior to subjecting the same to crosslinking irradiation. Once irradiated, the UHMWPE blended product may be machined, packaged, and sterilized in accordance with conventional techniques.

Abstract: An article suitable for use as an insulating or coating material comprises a radiation-crosslinked composition comprising a polyethylene, a polypropylene and optionally an ethylene-propylene elastomer. The polyethylene component is selected from high density polyethylene (HDPE), medium density polyethylene (MDPE) and linear medium density polyethylene (LMDPE) and the polypropylene component is either a homopolymer or copolymer. The composition is predominantly based on the polyethylene component and contains the polyethylene component in an amount of at least 50 percent by weight. The article is radiation-crosslinked to a sufficient degree that it possesses thermoset properties, such that when the article is heated to a temperature above the crystalline melting point of the polypropylene homopolymer or copolymer, it is softened but does not become liquid.

Abstract: Monomers (e.g. thinphenes) are caused to polymerise by mixing them with an oxidising agent (and generally a solvent comprising water) and irradiating the mixture with light (visible or UV). Polymer properties can be varied by doping or chemical modification. Uses include sensor elements for assays and electrical components such as electrodes.

Abstract: Modified polyolefins are produced by reacting a functionalized polyolefin with one or more ethylenically unsaturated compounds having a functional group reactive with the functional group on the polyolefin. These modified polyolefins may then polymerize in the presence of a photoinitiator upon exposure to ultraviolet radiation and also have the capability of copolymerizing in the presence of a photoinitiator with other ethylenically unsaturated crosslinking agents upon exposure to ultraviolet radiation. These modified polyolefins may also contain pendant carboxyl groups, which have the propensity to form hydrophilic salts with amines, and therefore may be rendered water-dispersible. The modified polyolefins of the present invention significantly improve the adhesion of paints, inks, and adhesives to various plastic and metal substrates.

Abstract: A 1,4-di-substituted diacetylene polymer that is soluble in organic solvent, is composed of a repeating unit represented by the general formula ?CR—C?C—CR?? (wherein, R and R? represent identical or different monovalent organic substituents), and has an average degree of polymerization of 4 to 200 and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight corresponding to said average degree of polymerization (Mn) of 1.1 to 5.0, and a process for producing the 1,4-di-substituted diacetylene polymer by irradiating a solution of the soluble 1,4-di-substituted diacetylene polymer with laser light having a wavelength within the range of 250 to 1,200 nm, and preferably 550 to 900 nm, to cause a photodegradation reaction of said polymer, or heating a solution of the soluble 1,4-di-substituted diacetylene polymer to a temperature of 100 to 300° C.

Abstract: An adhesive composition of the present invention comprises (A) a conjugated diene polymer having a weight-average molecular weight of 500 to 100,000 and (B) an electron pair-donating basic compound; or comprises (A) a conjugated diene polymer having a weight-average molecular weight of 500 to 100,000, (C) a compound having in its molecule three or more functional groups selected from the group consisting of acryloyloxy group, methacryloyloxy group and groups represented by the following formula I: wherein R1, R2 and m are the same as defined in the specification, and (D) a compound having in its molecule one or two functional groups selected from the group consisting of acryloyloxy group and methacryloyloxy group. At least a part of the surface of an adherend is coated with the adhesive composition to form an adhesive layer.

Abstract: The present invention provides an irradiated crosslinked polyethylene containing reduced free radicals, preferably containing substantially no residual free radical. Disclosed is a process of making irradiated crosslinked polyethylene by irradiating the polyethylene in contact with a sensitizing environment at an elevated temperature that is below the melting point, in order to reduce the concentration of residual free radicals to an undetectable level. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein.

Abstract: A polymerization process with elevated productivity using a coordination catalyst, wherein electromagnetic radiation is applied during polymerization. The irradiation of light greatly increases the activity of the coordination catalyst.

Abstract: A method is provided for making a crosslinked polymer electrolyte, typically in the form of a membrane for use as a polymer electrolyte membrane in an electrolytic cell such as a fuel cell, as well as the polymer so made, the method comprising application of electron beam radiation to a highly fluorinated fluoropolymer comprising: a backbone derived in part from tetrafluoro-ethylene monomer, first pendent groups which include a group according to the formula —SO2X, where X is F, Cl, Br, OH or —O?M+, where M+ is a monovalent cation, and second pendent groups which include Br, Cl or I. Typically, the membrane has a thickness of 90 microns or less, more typically 60 or less, and most typically 30 microns or less.

Abstract: The present invention relates to a fluororubber molded article obtained by subjecting a fluororubber composition to crosslinking by irradiation of ionizing radiation, wherein the fluororubber composition comprises: (i) a raw rubber having a metal element content of 1.5% or less and comprising a tetrafluoroethylene-propylene copolymer; and (ii) a prepolymer of triallyl isocyanurate. Also disclosed is a method for producing the fluororubber molded article.

Abstract: A method of making a crosslinked polymer is provided as well as the polymer so made, the method comprising the steps of: providing a highly fluorinated fluoropolymer, typically a perfluorinated fluoropolymer, comprising pendent groups which include a group according to the formula —SO2X, where X is F, Cl, Br, OH, or —O?M+, where M+ is a monovalent cation, and exposing said fluoropolymer to electron beam radiation so as to result in the formation of crosslinks. Typically, the method according to the present invention additionally comprises the step of: forming said fluoropolymer into a membrane, typically having a thickness of 90 microns or less, more typically 60 microns or less, and most typically 30 microns or less.

Abstract: A method is provided for obtaining crosslinked polymers, particularly fluorinated polymers having pendent sulfonic acid groups, by crosslinking through pendent groups which include a sulfonyl chloride group (—SO2Cl). The sulfonyl chloride group may be removed by application of electromagnetic radiation, typically in the ultraviolet band, or a radical initiator, leaving behind a radical which readily binds covalently to other polymer strands or to crosslinking agents to form crosslinks. Typically, the polymer is made by providing a polymer comprising pendent groups which include a group according to the formula —SO2F and converting at least a portion of the —SO2F groups to —SO2Cl. After crosslinking, the remaining —SO2F groups may be converted to sulfonic acid groups, yielding a crosslinked polymer electrolyte. Such crosslinked polymer electrolytes may be used to make polymer electrolyte membranes (PEM's) that may be used in electrolytic cells such as fuel cells.

Abstract: A method is provided for making a crosslinked polymer electrolyte, typically in the form of a membrane for use as a polymer electrolyte membrane in an electrolytic cell such as a fuel cell, by trimerization of nitrile groups contained on groups pendant from the polymer. The resulting polymer electrolyte membrane comprises a highly fluorinated polymer comprising: a perfluorinated backbone, first pendent groups which comprise sulfonic acid groups, and crosslinks comprising trivalent groups according to the formula: The first pendent groups are typically according to the formula: —R1—SO3H, where R1 is a branched or unbranched perfluoroalkyl or perfluoroether group comprising 1–15 carbon atoms and 0–4 oxygen atoms, most typically —O—CF2—CF2—CF2—CF2—SO3H or —O—CF2—CF(CF3)—O—CF2—CF2—SO3H.

Abstract: The invention provides a sterile medical implant or medical implant part comprising ultrahigh molecular weight polyethylene that has a molecular weight of about 400,000 atomic mass units or more. The invention also provides methods for producing, using, and preparing a medical implant or medical implant part, which comprise contacting the medical implant or medical implant part with water, such that the weight of the ultrahigh molecular weight polyethylene is increased, and the wear performance of the medical implant or medical implant part desirably is enhanced.

Abstract: A method is provided for forming a plastic prosthesis bearing, net-shape bearing, near net-shape bearing or plastic stock from which such a bearing can be formed. The method includes the steps of providing plastic resin in powdered form, subjecting the powdered resin to irradiation to cross-link the resin, and molding the irradiated powder. The irradiated powder is molded by applying heat and pressure to form the powder into a desired solid plastic shape, the heating being sufficient to melt the powder.

Abstract: A medical implant of ultrahigh molecular weight polyethylene having an improved balance of wear properties and oxidation resistance is prepared by irradiating a preform of ultrahigh molecular weight polyethylene, annealing the irradiated preform in the absence of oxygen to a temperature at or above the onset of melting temperature, and forming an implant from the stabilized cross-linked polymer. Implants prepared according to the process of the present invention have comparable oxidation resistance and superior wear performance compared to unirradiated ultrahigh molecular weight polyethylene.

Abstract: A medical implant of ultrahigh molecular weight polyethylene having an improved balance of wear properties and oxidation resistance is prepared by irradiating a preform of ultrahigh molecular weight polyethylene, annealing the irradiated preform in the absence of oxygen to a temperature at or above the onset of melting temperature, and forming an implant from the stabilized cross-linked polymer. Implants prepared according to the process of the present invention have comparable oxidation resistance and superior wear performance compared to unirradiated ultrahigh molecular weight polyethylene.

Abstract: A medical implant of ultrahigh molecular weight polyethylene having an improved balance of wear properties and oxidation resistance is prepared by irradiating a preform of ultrahigh molecular weight polyethylene, annealing the irradiated preform in the absence of oxygen to a temperature at or above the onset of melting temperature, and forming an implant from the stabilized cross-linked polymer. Implants prepared according to the process of the present invention have comparable oxidation resistance and superior wear performance compared to unirradiated ultrahigh molecular weight polyethylene.

Abstract: Wear resistance and oxidation resistance of polymer material or a polymer component for bioimplantation are improved by packaging a polymer object in a sealed gas impermeable package substantially free of oxygen, irradiating the package with penetrating radiation to an extent sufficient to effect a desired substantial level of cross-linking within the polymer, and warming the packaged object while maintaining an elevated hydrostatic pressure to cause gases released during irradiation to recombine, stabilizing the material against subsequent oxidative change. The pressure stabilization terminates active sites, substantially eliminating free radicals. When applied to finished parts, the process simultaneously hardens and sterilizes the parts without degrading mechanical properties or dimensions. When applied to bulk material or unfinished parts, the part may be subsequent machined or otherwise finished, and sterilized by any conventional means.

Abstract: The invention relates to a composition comprising polymerizable material and an anionic photocatalyst. The photocatalyst is a photolabile compound able to liberate a strong base having a pK.sub.a .gtoreq.12. The catalyst can be illustrated by the structural formula Z-A wherein Z is a photolabile group and A is a strong base, for example, a nitrogen containing compound such as, a secondary amine, a guanidine or amidine and Z is covalently bound to A.

Abstract: A process for the manufacture of rubber polymerizates comprising the steps of treating said rubber polymerizate with electron beam radiation to adjust the gel content and swelling index of said rubber polymerizate.

Abstract: A medical implant of ultrahigh molecular weight polyethylene having an improved balance of wear properties and oxidation resistance is prepared by irradiating a preform of ultrahigh molecular weight polyethylene, annealing the irradiated preform in the absence of oxygen to a temperature at or above the onset of melting temperature, and forming an implant from the stabilized cross-linked polymer. Implants prepared according to the process of the present invention have comparable oxidation resistance and superior wear performance compared to unirradiated ultrahigh molecular weight polyethylene.

Abstract: An ionic compound comprising at least one group A.sup.+ X.sup.-, comprising:a cationic group A.sup.+ selected from the group consisting of biaryliodonium, arylsulfonium, arylacylsulfonium, diazonium and organometallic cations comprising a transition metal complexed with at least one unsaturated cyclic compound comprising 4-12 carbon atoms, said cationic group being part of a polymer chain; whereinX.sup.- is an imide anion, [FSO.sub.2 NSO.sub.2 R'.sub.F ].sup.- or [R.sub.F CH.sub.2 OSO.sub.2 NSO.sub.2 R'.sub.F ].sup.- or [(R.sub.F).sub.2 CHOSO.sub.2 NSO.sub.2 R'.sub.F ].sup.-, or a methylide anion [FSO.sub.2 C(Q)SO.sub.2 R'.sub.F ].sup.-, or a [R.sub.F CH.sub.2 OSO.sub.2 C(Q)SO.sub.2 R'.sub.F ].sup.- or [(R.sub.F).sub.2 CHOSO.sub.2 C(Q)SO.sub.2 R'.sub.F ].sup.31 .

Abstract: A method for the anionic photoinitiation of polymerization or crosslinking of a substrate by irradiating a mixture of a substrate and a photoinitiator, where the photoinitiator is an inorganic transition metal complex which releases on irradiation a polymerization initiating substance consisting essentially of an anionically charged nucleophile that initiates the polymerization or crosslinking reaction, under conditions that allow the anion to initiate polymerization. FIG. 3 is plot of percentage polymerization of ethyl .alpha.-cyanoacrylate containing different concentration of Reineckate's anion.