Hidetoshi Hirahara

Adhesion of ABS resin to metals treated with triazine trithiol monosodium aqueous solution

An examination was made of the adhesion of ABS resin to treated metals such as phosphor bronze, brass plates, and electronickel platings during injection molding. No adhesion to any of these metals was noted to occur under ordinary injection molding conditions, and an aqueous solution of 1,3,5-triazine-2,4,6-trithiol monosodium (TTN) was thus used to induce adhesion. Following treatment with TTN aqueous solution under optimum conditions, ABS adhered tightly to all the above metals under ordinary injection molding conditions. TTN treatment led to the formation of surface films containing metal salts of 1,3,5-triazine-2,4,6-trithiol (TT). Conditions were made optimal with regard to time, temperature, and TTN concentration. Adherent films were generally formed when bronze and brass were treated for short periods, at low temperature, and at low TTN concentration, though not so in the case of nickel plating. There was adhesion to nickel plating in the case of prolonged treatment time, high temperature, and hig...

Influence on friction force of adhesion force between vulcanizates and sliders

Abstract The effects of vulcanizate and slider surface free energy—as well as the adhesion force (P) between them—on friction the force (F) and the coefficient of friction (μ) has been investigated. SBR and NBR vulcanizates were prepared using three molds differing in surface free energy. The mold with a high surface free energy gave a vulcanizate surface possessing polar groups. The mold with low surface energy gave a vulcanizate surface with many nonpolar groups. The coefficient of friction increased with the surface free energy of SBR and NBR vulcanizates. With SBR vulcanizate (surface free energy, 31.3 mJ·m−2) and teflon slider (surface free energy, 28.1 mJ·m−2) combination having the least surface free energy, the coefficient of friction was constant at greater than a 0.2N load. With vulcanizates and an aluminum slider with high surface free energy, friction force could be detected even at zero load because of the adhesion force at the interface. Friction force increased linearly with adhesion force ...

Adhesion of nylon-6 to triazine trithiol-treated metals during injection molding

Abstract —An examination was made of the adhesion of nylon-6 resin to treated metals such as phosphor bronze, brass plates, and electronickel platings during injection molding. No adhesion to any of these metals was noted to occur under ordinary injection molding conditions and an aqueous solution of 1,3,5-triazine-2,4,6-trithiol mononatrium (TTN) was thus used to induce adhesion. Following treatment with aqueous TTN solution under optimal conditions, nylon-6 adhered tightly to all the above metals under ordinary injection molding conditions. The TTN treatment led to the formation of surface films containing metal salts of 1,3,5-triazine-2,4,6-trithiol (TT). Conditions were made optimal with regard to time, temperature and TTN concentration. Adherent films were generally formed when bronze and brass were treated for short periods, at low temperature, and at low TTN concentration, although this was not the case with nickel plating. There was no adhesion to nickel plating even for a prolonged treatment time, high temperature, and high TTN concentration. Adherent and non-adherent films did not differ in the chemical structures of the metal salts of TT but they did differ in morphology. Good adhesion was noted in the case of TT-metal salts present at low density on the metal surface. Some films readily reacted with amino compounds under conditions similar to those generally used for the injection molding of nylon. The adhesion was concluded to be due to the formation of interfacial bonds during injection molding.

Effect of Triazine Dithiols on the Polymer Plating of Magnesium Alloys

2- Substituted (R)-1,3,5- triazine-4,6-dithiols (triazine dithiols ) with different alkyl chain lengths as substituents were prepared by the reaction of cyanuric chloride, dialkylamines and NaSH. Triazine dithiols were found to polymerize electrochemically on magnesium alloy (AZ91) plates. This method for coating metals is called polymer plating In the polymer plating of triazine dithiols on magnesium alloy plates, an aqueous 1M-NaOH solution was selected for the formation of polymer films and the suppression of side reactions. To select the optimal conditions for the formation of polymer films and the suppression of side reactions, plating factors such as the electrolyte, temperature, concentration, potential and current density were investigated. The films formed were composed of a polymer film, Mg(OH)2 and MgO, and the chemical structure of the films is discussed. The contact angle of the polymer films increased with the length of the alkyl chain and became constant for a chain length of six carbons. Polymer films with a 98° contact angle had a top surface completely covered all by CH3 - groups and not by - CH2- The alkyl chains were oriented in the vertical direction and were closely packed. Among the five polymer films studied real impedance (Rp) was the largest at about 27,000 Ω cm -2 - for the polymer film with a (C6H13)2N- subustituent The icorr of this polymer film was 5x 10 -7 A cm -2 2 The outstanding corrosion resistance of polymer film with a (C6H13)2N-subustituent is thought to result from the alkyl chains in the film that were highly oriented and closely packed.

Direct Adhesion between Electroless Nickel-P Plated Metals and NBR Compounds during Curing

Abstract In this study, an examination was made of the various causative factors for the direct adhesion between nickel-P alloy (nickel alloy) and acrylonitrile-butadiene rubber (NBR) compounds during curing. In a high sulfur curing system (SV), direct adhesion was found to depend on time of exposure to air and not to occur after more than 48 h of exposure. In the peroxide curing system (PV), there was no adhesion at all regardless of the exposure time. The addition of triazine thiols to NBR compounds resulted in adhesion between NBR compounds and nickel alloy for exposures exceeding 48 h. Typical curing systems such as SV, low sulfur curing (LSV), sulfurless curing (SLV), and PV gave good NBR-nickel adherends when the NBR compounds contained the monosodium salt of triazine trithiol (TTN). In these system, peel strength in the adherends increased with triazine thiols, to a maximum, and then decreased. This parameter was influenced by the chemical structures of triazine thiols, such as those containing thi...

CELLULAR UPTAKE BEHAVIOR OF FLUORESCEIN: INTERCALATED LAYERED DOUBLE HYDROXIDE

In order to define the ability of layered double hydroxide (LDH) as materials for drug delivery, fluorescein (Fluo) anion intercalated LDH (Fluo/LDH) was synthesized by hydrothermal treatment and observed the cellular uptake of the Fluo/LDH for mammalian cell (L929). The synthesized Fluo/LDH showed a LDH structure, high fluorescence and low cytotoxicity. According to the fluorescence, confocal and TEM images of cells, the Fluo/LDH seemed to be internalized into the L929 cell by cellular endocytosis and dissolved inside the cell to exhibit the fluorescence of cellular cytoplasm.

Direct adhesion of natural rubber to nickel/sulfur plating during curing

- Direct adhesion between natural rubber and nickel/sulfur plating during curing was investigated. A nickel/sulfur plating was obtained by the addition of sodium thiosulfate Na2S2O3 ·a 5H2O to a nickel chloride plating bath. The sulfur content of the plating depends on the concentration of sodium thiosulfate, Na2S2O3 · 5H2O, the bath temperature and the plating current density. The nickel/sulfur plating is deposited in an amorphous form and the sulfur is distributed uniformly. When the nickel/sulfur plating and natural rubber are cured in a hot press, direct adhesion is formed. The sulfur content around 30% gives the best adhesion and a thinner plating is preferable. The amorphous nickel/sulfur plating is transformed to a crystalline phase [mixture of α-nickel and nickel sulfide (Ni3S2)] during curing. It is suspected that less heat stress is generated in the case of a thinner plating which causes better adhesion to rubber.

Direct adhesion of fluorinated rubbers to nickel-plated steel and nitrile rubber during curing using the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol

A new curing agent, the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol (TATT) for fluorinated rubber (FR) has been developed, from the point of view of making composite materials with metals and other rubbers. TATT was inferior in curing rate compared with a conventional polyol curing system, but imparted good properties to FR vulcanizates to the same extent as the polyol curing system. TATT-containing FR compounds easily adhered to electro- and electroless nickel-plated metals during vulcanization without an adhesive. The optimum concentration of TATT was around 1 phr for the peel strength of joints and the mechanical properties of vulcanizates. At a thickness exceeding 0.3 μm, nickel platings were very effective for making FR-Ni joints. In the direct adhesion between FR and nickel platings, interfacial bonds and a reinforcing layer at the interface between vulcanizates and nickel platings during vulcanization were important for obtaining FR-Ni joints of high peel strength. The newly prepared F...

Formation of Surface Structure in Vulcanizates and Surface Structure Changes in Air

Abstract The formation theory of surface structure during vulcanization was developed on the basis of an interfacial concept. The theory showed the chemical compositions of polar and nonpolar components on the vulcanizate surface to be determined as an excess interfacial free energy between rubber compounds and molds decreases. The surface free energies of molds reflected clearly the corresponding surface free energy of vulcanizates prepared from copolymers and polar polymers. Nonpolar polymers were not influenced by the surface free energies of molds. The surface free energies of vulcanizates decreased slightly with the concentration of network chains owing to the entropy of rubber segments. The surface free energies of molds affected the chemical compositions at the topmost surface region to the upper surface region on vulcanizates. NBR vulcanizates with high surface free energy increased the contact angle of water after standing in dry air. In the dry air environment, topmost surface layer nitrile grou...

Electropolymerization of aniline on conductive vulcanizates and charge-discharge properties

Abstract To obtain electrode materials with good charge-discharge properties, the electrochemical polymerization of aniline on conductive vulcanizates containing Ketjin black was investigated along with the charge-discharge properties of these materials. When EPDM vulcanizates containing Ketjin black greater than 20 phr were used as working electrodes, the polymerization of aniline occurred easily and conductive laminates of vulcanizate and polyaniline were obtained. This required an EPDM vulcanizate conductivity of more than 0.1 S/cm. The selection of elastomers and solvents for the electrochemical reaction is important. A combination of EPDM and water solvent was found to be suitable for the electrochemical polymerization of aniline. Polyaniline products on vulcanizate electrodes had lower film densities than polypyrrole products, and exhibited greater adhesion to the vulcanizates than to Pt electrodes. Li battery cells, using these polyaniline vulcanizate electrodes, possessed remarkably higher charge-...