The glass transition temperature of nonstoichiometric epoxy–amine networks

Glass transition temperatures (T_g) of nonstoichiometric epoxy-amine networks based on the diglycidylether of bisphenol A (DGEBA), are analyzed in terms of the network structure. In most cases reasonable predictions of T_g can be made using an empirical equation reported by L. E. Nielsen together with the experimental T_g value of the stoichiometric network and statistical calculations of the concentration of elastic chains. It is stated that in these rigid networks the concentration of elastic chains is the main structural factor associated to the variations of T_g with stoichiometry. For flexible networks based on the diglycidylether of butanediol (DGEBD), the effect of elastic chains on the T_g value is much less significant.     

Investigation of a waterborne epoxy for E‐glass composites

We present a continuing investigation of epoxies based on diglycidyl ether of bisphenol A cured with 2‐ethyl‐4‐methylimidazole in the presence of the nonionic surfactant Triton X‐100. Interest in this epoxy system is due partially to its potential application as a waterborne replacement for solvent‐cast epoxies in E‐glass‐laminated printed circuit boards. The surfactant additive could potentially alter the interfacial properties and durability of composite materials. Previous studies revealed that the viscoelastic behavior of the cured epoxy is altered when it serves as the matrix in a glass‐fiber‐reinforced composite. The additional constraining and coupling of the E‐glass fibers to the segmental motion of the epoxy matrix results in an apparent increased level of viscoelastic cooperativity. Current research has determined that the cooperativity of an epoxy/E‐glass composite is also sensitive to the surface chemistry of the glass fibers. Model epoxy/E‐glass composites were constructed in which the glass was pretreated with either 3‐aminopropyltriethoxysilane or 3‐glycidoxypropyltrimethoxysilane coupling agents. Dynamic mechanical analysis was then used to create master curves of the storage modulus in the frequency domain. The frequency response of the master curves and resulting cooperativity plots clearly varied with the surface pretreatment of the glass fibers. The surfactant had surprisingly little effect in the observed trends in the cooperativity of the composites. However, the changes in cooperativity due to the surface pretreatment of the glass were lessened when the samples were prepared from waterborne emulsions. Moisture‐uptake experiments were also performed on epoxy samples that were filled with spherical glass beads as well as multi‐ply laminated composites. No increases in the diffusion constant could be attributed to the surfactant. However, the surfactant did enhance the final equilibrium moisture‐uptake levels. These equilibrium moisture‐uptake levels were also sensitive to the surface pretreatment of the E‐glass. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2351–2365, 2000     

Nanostructures of polyelectrolyte gel–surfactant complexes

Small‐angle X‐ray scattering was used to investigate the nanostructures of complexes formed by slightly crosslinked anionic copolymer gels of poly(sodium methacrylate‐co‐N‐isopropylacrylamide) [P(MAA/NIPAM)] with cetyltrimethylammonium bromide (CTAB), and didodecyldimethylammonium bromide (DDAB), respectively, at room temperature (∼ 23°C). Several highly ordered supramolecular structures were observed in the polyelectrolyte gel–surfactant complexes. In P(MAA/NIPAM)–CTA systems, in sequence with decreasing charge density of the P(MAA/NIPAM) copolymer chains, structures of the Pm3n space group cubic, face‐centered cubic close packing of spheres, and hexagonal close packing of spheres were determined at a charge content of ≥ 75, 67, and 50%, respectively. The spheres and rods in these structures were the spherical and cylindrical micelles formed by the self‐assembly of CTA cations with their paraffin chains inside. Both the aggregation number and the size of the micelles decreased with a decreasing charge density of the copolymer chains. In the P(MAA/NIPAM)–DDA systems, the bilayer lamellar structures formed at charge contents ≥ 75% transferred to bicontinuous cubic structures of the Ia3d space group at charge contents of 50–67%. The rods in the Ia3d cubic structures were formed by the self‐assembly of double‐tailed DDA cations with polar moieties inside. The formation of these highly ordered structures were driven by both electrostatic and hydrophobic interactions of the charged copolymer chains/surfactants and the surfactants/surfactants inside the charged gels. The structures became less ordered by further decreasing the charge content of the P(MAA/NIPAM) chains. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2165–2172, 1999     

Simultaneous kinetic and microdielectric studies of some epoxy–amine systems

Three reactive epoxy–amine systems based on diglycidyl ether of bisphenol A (DGEBA) with 4,4′-diaminodiphenylsulfone (DDS), 4,4′-methylenebis [3-chloro 2,6-diethylaniline] (MCDEA), and 4,4′-methylenebis [2,6-diethylaniline] (MDEA), were studied during isothermal curings at 140 and 160°C. The simultaneous kinetic and dielectric studies allow to express conductivity, σ, in terms of conversion, x, and of glass transition temperature, T_g. The conductivity, σ₀, of the initial monomer mixture and, σ_∞ of the fully cured network are measured. It is found that:

• The glass transition temperature, T_g, versus conversion, x, curves follows the equation of Di Benedetto modified by Pascault and Williams
• There exists a linear relation between log σ/log σ₀ and T_g.

So, it is possible to predict both kinetic and dielectric behaviors of these epoxy-amine systems by the knowledge of T_g0, ΔC_p0, and σ₀, respectively, glass transition temperature, heat capacity, and conductivity of initial monomer mixture, T_g∞ and ΔC_p∞, and σ_∞, respectively, glass transition temperature and heat capacity and conductivity of fully cured network. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2911–2921, 1998     

Electrokinetic characterization of polystyrene–non-ionic surfactant complexes

An experimental study on the electrophoretic mobility (μ_e) of polystyrene particles after the adsorption of non-ionic surfactants with different chain lengths is described. Two sulphate latexes with relatively low surface charge densities (3.2 and 4.8 μC cm⁻²) were used as solid substrate for the adsorption of four non-ionic surfactants, Triton X-100, Triton X-165, Triton X-305 and Triton X-405, each one with 9–10, 16, 30 and 40 molecules of ethylene oxide (EO), respectively. The electrophoretic mobility of the polystyrene–non-ionic surfactant complexes was studied versus the amount of adsorbed surfactant (Γ). The presence of non-ionic surfactant onto particles surface seems to produce a slight shifting of the slipping plane because the mobilities of the different complexes display a very small decreasing. The increase in the number of EO chains in the surfactant molecule seems to operate as a steric impediment which decreases the number of adsorbed large surfactant molecules. The electrophoretic mobilities of the latex–surfactant complexes with maximum adsorption were measured versus the pH and ionic strength of the dispersion. While the different complexes showed a similar qualitative behaviour compared with that of the bare latex against the pH, the adsorption of the surfactant reduces the typical maximum in the μ_e−log[electrolyte].     

Preparation and properties of high performance epoxy–silsesquioxane hybrid resins prepared using a maleimide–alkoxysilane compound as a modifier

An alkoxysilane compound possessing maleimide moiety (MSM) was prepared from N‐(4‐hydroxyphenyl)maleimide and 3‐glycidoxypropyltrimethoxysilane and was used as a modifier of epoxy resins. In situ curing epoxy resins with MSM resulted in epoxy resins with good homogeneity. Just 5–10 wt % of MSM is sufficient to yield high glass transition temperature (165 °C), good thermal stability above 360 °C, and high flame retardancy (LOI = 30) to bisphenol‐A‐based epoxy resins. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5787–5798, 2005     

Mechanism of transesterification and cyclization of epoxy–polycarbonate blends catalyzed by quarternary ammonium salt

The reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by the transesterification reaction of the oxirane cycle with the carbonate group that proceeds by an “insertion” mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. In the nonstoichiometric system, the epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. To identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). The mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. © 1996 John Wiley & Sons, Inc.     

The interactions of surfactant viologens with cyclodextrins

N-ethyl-N-hexadecyl-4,4-bipyridinium bromide (C₁₆VBr₂) andN-ethyl-N-octadecyl-4,4-bipyridinium bromide (C₁₈VBr₂) were used as electroactive probes to assess the interactions between surfactants and cyclodextrins. Cyclic voltammetry, visible spectroscopy, fluorescence spectroscopy and surface tension techniques were used to detect the formation of complexes between the surfactant viologen probes and- and-cyclodextrins. The voltammetric results suggest the formation of inclusion compounds in which the hydrophobic tail of the surfactant viologens penetrate the cyclodextrin cavity. The dimerization of the viologen cation radicals is essentially suppressed by the presence of-cyclodextrin (ACD) while no effects are observed in the presence of-cyclodextrin (BCD). The observed results are best explained by the relative solubility in aqueous media of each of the inclusion complexes in the several accessible viologen oxidation states.     

Cure behavior and thermal degradation mechanisms of epoxy and epoxy–cyanate resins

The cure reactions of tetraglycidyl methylene diamine (TGMDA) epoxy cured with tetrasubstituted aromatic diamine on one hand and diglycidyl ether of bisphenol A and diglycicyl ether tetrabromobisphenol A epoxies cured with methylene bis (phenyl‐4‐cyanate) on the other hand are reported. Systematic Fourier transform infrared (FTIR) spectroscopy studies of the cure reaction of epoxy and epoxy–cyanate during thermal cycles are presented. FTIR studies indicate that the reaction of TGMDA monomer is total but the network contains a large amount of primary amine. The cyanate monomer reacts rapidly to form triazine structures. Then the epoxy monomers homopolymerize and crosslink with free cyanate groups. The gas chromatography/mass spectrometry study of volatile products evolved during the polymer thermal degradation shows the dehydration of the epoxy network and the decomposition of the amine structure. The FTIR and solid‐phase ¹³C nuclear magnetic resonance analysis revealed that the ether functions and the amine groups are temperature sensitive but the triazine structure is not. Copyright © 1999 John Wiley & Sons, Ltd.     

Application of size exclusion chromatography with surfactant eluent to the study of polymer–surfactant interactions: oligomeric and micellar chromatographic effects

Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol⁻¹. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol⁻¹) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol⁻¹ PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.     

The epoxy–polycarbonate blends cured with aliphatic amine—I. Mechanism and kinetics

Reaction mechanism of the PC–epoxy blends cured by aliphatic amine has been investigated by varying PC contents in the blends. The transamidation reaction tends to convert nearly all the carbonates into N-aliphatic aromatic carbamates even at ambient temperature before normal curing. The remaining amine proceeds the normal curing with epoxy at a higher temperature (80°C). For the PC–epoxy/aliphatic amine blend containing 6 wt % PC, the yielded N-aliphatic aromatic carbamate further reacts with amine to produce the urea structure. The urea undergoes substitution reaction with the hydroxyl formed from the normal curing to give the N-aliphatic aliphatic carbamate. For the blend containing 12 wt % PC, the N-aliphatic aromatic carbamate converts into the N-aliphatic aliphatic carbamate via two different routes. For the blend containing lower molecular weight of the aliphatic amine, the N-aliphatic aromatic carbamate reacts with hydroxyl to form the N-aliphatic aliphatic carbamate directly. For the blend containing higher molecular weight of aliphatic amine, the N-aliphatic aromatic carbamate decomposes into the aliphatic isocyanate accelerated by the presence of the residual oxirane. The isocyanate formed then reacts with hydroxyl to yield the N-aliphatic aliphatic carbamate. The activation energy (E_a) and preexponential factor (A) of the PC–epoxy/POPDA blends decrease with the increase of the PC content. Kinetic study by thermal analysis by the method of autocatalyzed model is able to correctly predict oxirane conversion vs. time relationship for the neat epoxy/aliphatic amine and the PC–epoxy/aromatic amine systems because the dominant reaction is the normal curing reaction between amine and oxirane. The model fails to predict the PC–epoxy/aliphatic amine system because the system is complicated by several other reactions besides the normal curing reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2169–2181, 1997     

Effect of crosslink length on the enthalpy relaxation of fully cured epoxy–diamine resins

Enthalpy relaxation of epoxy–diamine thermosets of different crosslink lengths (CLL) has been studied by DSC. The epoxy resins based on diglycidyl ether of bisphenol A were cured with ethylenediamine (FEDA), and diamines of polyoxypropylene of 2.6 and 5.6 oxypropylene units, named FJ230 and FJ400, respectively. As was expected, increasing the CLL decreases the glass transition temperature T_g from 121°C (FEDA) to 47°C (FJ400). Aging experiments at T_g − 20 K for each resin permit the determination of the enthalpy loss, the relaxation rate per decade (β_H), and the nonlinearity parameter, x. The apparent activation energy, Δh*, and the nonexponentiality parameter β are found for each resin from intrinsic cycles in which the sample is heated at 10 K min⁻¹ following cooling at various rates through the glass transition region. An increase of CLL is related to an increase of β_H, and of the nonlinearity parameter. In agreement with the general trend for thermoplastic polymers, the increase of the parameter x is correlated with a decrease of Δh* and with an increase in the nonexponentiality parameter. Application of the Adam–Gibbs (AG) theory reveals that the parameters B and T_f/T₂ increase with CLL, corresponding to a decrease of the nonlinear behavior of the glassy epoxies. However, the T₂ values calculated in this way appear unrealistic, and the alternative assumption that T₂ = T_g −51.6 K, making use of the “universal” WLF constant, leads to a much smaller variation of B, which nevertheless still increases with CLL. From a consideration of the minimum number of configurations required for a cooperative rearrangement, it is argued that the elementary activation energy Δμ increases, and the minimum size of the cooperatively rearranging region decreases as CLL increases. This is consistent with the relaxation process becoming more cooperative as the CLL decreases, as is suggested by the decrease in the value of β. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 456–468, 2000     

Enthalpy relaxation of an epoxy–anhydride resin by temperature‐modulated differential scanning calorimetry

The enthalpy relaxation of an epoxy–anhydride resin was studied by physical aging and frequency‐dependence experiments with alternating differential scanning calorimetry (ADSC), which is a temperature‐modulated differential scanning calorimetry technique. The samples were aged at 80 °C, about 26 K below the glass‐transition temperature, for periods up to 3800 h and then scanned under the following modulation conditions: underlying heating rate of 1 K min⁻¹, amplitude of 0.5 K, and period of 1 min. The enthalpy loss was calculated by the total heat‐flow signal, and its variation with the log (aging time) gives a relaxation rate (per decade), this value being in good agreement with that calculated by conventional DSC. The enthalpy loss was also analyzed in terms of the nonreversing heat flow, revealing that this property is not suitable for calculating enthalpy loss. The effect of aging on the modulus of the complex heat capacity, |Cp*|, is shown by a sharper variation on the low side of the glass transition and an increase in the inflexional slope of |Cp*|. Likewise, the phase angle also becomes sharper in the low‐temperature side of the relaxation. The area under the corrected out‐phase heat capacity remains fairly constant with aging. The dependence of the dynamic glass transition, measured at the midpoint of the variation of |Cp*|, on ln(frequency) allows one to determine an apparent activation energy, Δh*, which gives information about the temperature dependence of the relaxation times in equilibrium over a range close to the glass transition. The values of Δh*, determined from ADSC experiments in a range of frequencies between 4.2 and 33 mHz and at an amplitude of 0.5 K, and an underlying heating rate of 1 K min⁻¹, were analyzed and compared with that obtained by conventional DSC from the dependence of the fictive temperature on the cooling rate. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2272–2284, 2000     

Dynamic mechanical properties of epoxy‐phenolic mixtures

The dynamic‐mechanical properties of different mixtures formed by an epoxy resin (DGEBA type) and a phenolic resin (resole type) cured by trietylenetetramine and/or p‐toluensulphonic acid at different concentrations have been studied by means of dynamic mechanical thermal analysis (DMTA). All samples were cured by pressing at 90 °C during 6 h. The mechanical studies were performed between ?100 to 300 °C at a heating rate of 2 °C/min. This study was also carried out for the epoxy‐TETA and phenolic‐p‐toluensulphonic acid systems. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1548–1555, 2005     

Three-phase contact parameters measurements for silica-mixed cationic–anionic surfactant systems

The stability and interactions in thin wetting films between the silica surface and air bubble containing (a) straight chain C₁₀ amine and (b) cationic/anionic surfactant mixture of a straight chain C₁₀ amine with sodium C₈, C₁₀ and (straight chain) C₁₂ sulfonates, were studied using the microscopic thin wetting film method developed by Platikanov [D. Platikanov, J. Phys. Chem. 68 (1964) 3619]. Film lifetimes, three-phase contact (TPC) expansion rate, receding contact angles and surface tension were measured. The presence of the mixed cationic/anionic surfactants was found to lessen contact angles and suppresses the thin aqueous film rupture, thus inducing longer film lifetime, as compared to the pure amine system. In the case of mixed surfactants heterocoagulation could arise through the formation of positively charged interfacial complexes. Mixed solution of cationic and anionic surfactants shows synergistic lowering in surface tension. The formation of the interfacial complex at the air/solution interface was confirmed by surface tension data. It was also shown, that the chain length compatibility between the anionic and cationic surfactants system controls the strength of the interfacial complex. The observed phenomena were discussed in terms of the electrostatic heterocoagulation theory, where the interactions can be attractive or repulsive depending on the different surface activity and charge of the respective surfactants at the two interfaces.     

Surface modification of epoxy‐functionalized acrylate colloids

A synthetic route towards surface modified, monodisperse, spherical particles is presented. The precursor particles exhibit epoxy‐functionalities which can be opened afterwards with an appropriate nucleophile. Via this route, dye labeled particles are obtained. Copyright © 2004 John Wiley & Sons, Ltd.     

Eutectic crystallization and hydrogen bonding interactions in polymer/surfactant blends

The unusual eutectic crystallization behavior in the poly(ε‐caprolactone) (PCL) and 3‐pentadecylphonel (PDP) binary blends was investigated by differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. A eutectic system was found with the eutectic composition at 60 wt % PDP and the eutectic melting temperature at 35 °C. The melting process of the blend at the eutectic composition was studied by in situ FTIR. The concurrence of the melting of PCL and PDP crystallites and the sequential formation of hydrogen bonding interaction between PDP molecules and PCL chains were traced. It was also found that a further increase in temperature above the eutectic melting temperature would impair the hydrogen bonding and increase the content of nonassociated phenol hydroxyl group. The semicrystalline morphology of blends affected by the composition was also investigated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1015–1023, 2009     

Characterization of synthetic and commercial trisiloxane surfactant materials

The organosilicone surfactant Silwet L‐77^® (L‐77), used as an agrochemical adjuvant, is a mixture comprised predominantly of [(CH₃)₃SiO]₂? (CH₃)Si? (CH₂)₃? (OCH₂CH₂)_n? OCH₃ oligomers (n = 3–16, average n ≈ 7.5). The commercially available L‐77 mixture was purified by reversed‐phase high‐performance liquid chromatography (HPLC) to obtain individual trisiloxane surfactant components. Pure oligomers (n = 3, 6 and 9) were also synthesized. Synthesis was achieved by hydrosilylation of monomeric ethoxylate monomethyl ether starting reagents. Pure hexa‐ and nona‐ethylene glycols were produced by condensation of smaller oligomers. Atmospheric‐pressure ionization mass spectrometry (MS) methods were used to characterize fully the commercial L‐77 product and synthesized or isolated components. The application of Fourier‐transform ion cyclotron resonance MS and online HPLC–electrospray ionization MS techniques to the analysis of this surfactant are described here. The application of these analytical techniques also enabled elucidation of the synthetic by‐products present in the commercial formulation. In addition, physico‐chemical properties specific to agrochemical uses, such as droplet spread areas on plant foliage and surface tension for the different oligomer solutions, are also reported. Copyright © 2004 John Wiley & Sons, Ltd.     

Flame retardant epoxy composites with epoxy‐containing polyhedral oligomeric silsesquioxanes

A kind of polyhedral oligomeric silsesquioxanes (POSS) containing the propoxyl‐epoxy and phenyl groups (pr‐ep‐Ph‐POSS) was synthesized via hydrolytic condensation reaction. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry identified the structure of the pr‐ep‐Ph‐POSS, including major caged Si₆O₉ (T6), Si₁₀O₁₅ (T10), Si₁₂O₁₈ (T12), etc. The pr‐ep‐Ph‐POSS was applied into the epoxy resin to achieve EP/pr‐ep‐Ph‐POSS composites. Thermogravimetric analysis indicated that EP/pr‐ep‐Ph‐POSS showed excellent thermal properties than pure EP. The fire behaviors of EP/pr‐ep‐Ph‐POSS composites were evaluated based on the cone calorimetry, limiting oxygen index (LOI), UL‐94 vertical burning test, and smoke density test. The smoke density decreased by ~30%, the LOI value reached to 26.4%, dripping was inhibited, and the peak of heat release rate decreased by ~62%. X‐ray photoelectron spectroscopy analysis and FTIR indicated that protective‐barrier effect is the main flame‐retardant mode of action for pr‐ep‐Ph‐POSS, due to the formation of the Si‐O‐Si, Si‐O‐C, and Si‐C condensed phase, which improve the thermal stability, strength, and integrity of the char layer.     

Regular microstructures in gel–surfactant complexes: Influence of water content and comparison with the surfactant structure in water

Interaction of slightly crosslinked hydrogels of poly(diallyldimethylammonium chloride) (PDADMACI) and of copolymer DADMACI/acrylamide (AAm) with sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfate (SDBS) results in significant shrinking of the gels due to the formation of polymer-surfactant complexes. Jump-wise transitions in the collapsed state were observed for the networks with the content of cationic groups 100 and 75 mol %. The structure of complexes was studied by means of X-ray scattering method. The scattering curves for collapsed gels, where most chloride anions were replaced by anions of SDS, show a set of well-pronounced narrow diffraction maxima. Fully charged “wet” complexes studied at the equilibrium swelling conditions exhibit high degree of ordering, which diminishes upon drying with the simultaneous transition from hexagonal to lamellar type of ordering. In contrast to this, for DADMACl/AAm copolymer gels (75 mol % of DADMACl monomers in the initial polymerization mixture) the ordering is less pronounced in the “wet” state and becomes more perfect upon drying. The SDS aqueous solutions of the same concentration in the absence of gel do not show such high degree of ordering, while the system of SDS/neutral AAm gel exhibits lamellar ordering typical for low-temperature phases of SDS solutions. © 1996 John Wiley & Sons, Inc.