Aqueous pretreatments of polyetherimide to facilitate the bonding of electrolessly deposited copper

A chemical method for pretreating polyetherimide substrates to promote adhesion to copper is described. The process consists of cleaning the polymer surface followed by surface normalization, debris solubilization, and adhesion promotion via chemical modification of the polymer surface. Classes of candidates for each of the major steps are described and the optimal agents assembled into a recommended procedure. Peel strengths between 150-210 g mm^-1 for copper to polyetherimide were achieved utilizing the suggested scheme. Scanning electron microscopic and X-ray photoelectron spectroscopic analyses were employed to investigate changes in the polymer surface and chemistry during processing. Metallized specimens were examined after 90° peel testing and the failure locus found to be within the polymer layer.     

Development and thermal durability of an interfacial bond between electrolessly deposited metals and a fluorinated polyimide

The oxygen content of a fluorinated polyimide surface can be increased by exposure to an oxidant such as an alkaline permanganate solution. Deposition of an electroless metal layer on this oxidized surface results in the formation of an interfacial bond which is predominantly chemical in nature. The level of adhesion achieved depends both on the surface oxidation conditions and post-plating heating. Adhesion maxima are obtained by heating to 200°C for an electroless Cu deposit and to 300°C, the cure temperature for the polyimide film, for deposited electroless Ni. The fluorinated polyimide used in this study was derived from the reaction of 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane with pyromellitic dianhydride and was obtained from Ethyl Corporation as Eymyd® L30N resin.     

清洗预处理对手表外观件表面镀类金刚石薄膜性能的影响

为解决手表外观件镀层的附着力和硬度不高而产生的膜层脱落和磨损露底等问题,采用阳极层流型气体离子源结合非平衡磁控溅射技术制备了类金刚石膜层,研究了镀前清洗工艺对膜层附着力和耐磨性能的影响.结果表明,所制备的类金刚石膜均匀亮黑,显微硬度为2 232 HV,摩擦系数为0.15.在同一镀膜工艺条件下,手表外观件经彻底清洗后,其...     

The effect of pretreatment of the metal surface on the bonding strength of a composite of strip steel,primer and PVC

Some parameters which influence the adhesion interactions in the interface layers of a multilayer system comprising strip steel, primer and polyvinyl chloride have been investigated. A distinct relationship was found between the pretreatment of the metal surface and the bonding strength, both of which were remarkably affected by the functional groups of the modified acrylate primer.     

Analysis of the Molecular Structure at the PPS/Copper Interphase and its Role in Adhesion

X-ray photoelectron spectroscopy (XPS) was used to examine the interfacial chemistry in polyphenylene sulfide (PPS)/copper bonded laminates. Several surface pretreatments were studied including a simple methanol wash, two acid etches, thermal oxidation and chemical oxidation. Peel test analysis showed poor adhesion to the methanol-washed and acid-etched foils, giving a peel strength of only 3-5 g/mm. XPS analysis of the failure surfaces revealed a large amount of inorganic sulfide at the interface with reduction of the copper oxide. Chemical oxidation using an alkaline potassium persulfate solution gave a matt-black surface consisting of primarily cupric oxide. These samples showed improved adhesion and XPS analysis of the failure surfaces revealed fracture through a mixed PPS/cuprous oxide layer. A simple thermal oxidation yielded a cuprous oxide surface layer and laminates bonded to these surfaces showed a more than ten-fold increase in peel strength. XPS analysis of the failure surfaces showed much lower amounts of interfacial copper sulfide and it was postulated that excess sulfide at the interface was responsible for the poor adhesion observed for other pretreatments.     

Removal of toxic metals from aqueous mixtures. Part 1: Biosorption

The biosorption of toxic metals from an aqueous mixture containing zinc, copper and nickel, in the presence of calcium and sodium ions (usual co‐existing cations in related systems) has been investigated. Industrial biomass samples of different origin have been examined batchwise as effective sorbents, including bacteria (Streptomyces rimosus), fungi (Penicillium chrysogenum) and yeasts (Saccharomyces carlsbergensis and Saccharomyces cerevisiae). The effect of solution pH was evaluated in the range of 3–11.5. Selectivity was observed, particularly for the removal of copper. The observed removal of metals by the application of biosorption was also compared in laboratory experiments with other more conventional separation techniques (filtration, centrifugation and flotation). © 1999 Society of Chemical Industry     

KDF过滤介质在反渗透预处理中的应用

介绍了一种反渗透预处理的新方法,阐述了应用KDF过波介质控制结垢形成,减少悬浮固体,减少氧化剂,控制细菌和藻类,减少重金属和减少硫化氢的机理,并给出了应用实例。     

Nickel interlayer on the microstructure and property of TC6 to copper alloy diffusion bonding

In the present study, diffusion bonding of two dissimilar materials TC6 and copper alloy was investigated in vacuum chamber by directly bonding and using Ni foil as interlayer. Interface quality of the joints was evaluated by mechanical property and microstructure. The maximum shear strength of directly bonding was found to be 64 MPa for the speciemen bonded at 850 °C, 5 MPa for 30 min; and the maximum shear strength with Ni foil interlayer was 113 MPa under the same bonding parameters. The bonding interfaces and fracture surfaces were analyzed by energy disperse spectrometer, scanning electron microscopy and X-ray diffraction. The results show that the diffusion region of directly bonding specimen generated several IMCs (Ti₂Cu and Ti₅CuSn₃, etc.). Fracture morphology showed that brittle fracture present at the Ti₅CuSn₃ IMCs, which was the weak point of the joint. While the diffusion zone of the specimen with Ni foil interlayer consists of various phase including Ti₂Ni, TiNi, TiNi₃ at TC6 side, and Cu-Ni solid solution at ZQSn11-4-3 side, and fracture surface of joint present a mixture of brittle and ductile characteristics, and fracture initiated at the TiNi₃/Ni interface.     

The effect of TiO2 morphology on the surface modification of poly (ethylene terephthalate) for electroless plating

In this study, a surface modification of the poly (ethylene terephthalate) (PET) film using TiO₂ photocatalytic treatment was investigated. In order to enhance the adhesion strength between the PET film and the electroless copper film, the effects of TiO₂ crystal forms, TiO₂ particle sizes, and TiO₂ content, as well as treatment condition, upon the surface contact angle, surface characterization, and adhesion strength were investigated. Anatase TiO₂ with a particle size of 5 nm had a high catalytic activity and dispersibility in aqueous solution. After the optimal photocatalytic treatment, the surface contact angle of the PET film decreased from 84.4° to 19.8°, and the surface roughness of the PET film increased from 36 to 117 nm. The adhesion strength between the PET film and the electroless copper film reached 0.89?KN?m^?1. X-ray photoelectron spectroscopy analyses indicated the carbonyl group was formed on the PET surface after photocatalytic treatment, and the surface hydrophilicity was improved. Consequently, TiO₂ photocatalytic treatment is an environmentally friendly and effective method for the surface modification of the PET film.     

Effect of bio-alkyd resin oil content and viscosity on the adhesion of EPDM to polyester fabric

Three types of bio-alkyd resins varies in their oil content and viscosity were added to EPDM rubber mix loaded by three bonding system consisting of Hexamethylenetetramine, Resorcinol and Hydrated silica (HRH). The mixes were charged by certain amount of thermal carbon black. Rubber dough was spread on polyester sheet fabric. The peel strength was used to measure the adhesion strength. The rubber-proofed fabric subjected to UV irradiation at different period of times. The dielectric constant, volume resistivity, thermal stability, water and air permeability of the various rubber coated fabric were examined. The addition of the bio-alkyd resin improved the various mechanical and physical properties of the rubber coated fabric materials. The suggested mechanism of bio-alkyd resin between EPDM and polyester fabric was also studied.     

Improvement in the adhesion between copper metal and polyimide substrate by plasma polymer deposition of cyano compounds onto polyimide

The surface modification of Kapton film by means of plasma polymer deposition is discussed from the viewpoint of improving the adhesion between copper metal and Kapton film substrate. Plasma polymers of AN (acrylonitrile) and FN (fumaronitrile) were used for the surface modification, and the adhesion between the copper metal and the plasma polymer-coated Kapton film was evaluated by the T-peel strength measurement. The surfaces of peeled layers were analyzed by X-ray photoelectron spectroscopy (XPS) and the failure mode is discussed. The plasma polymer deposition of AN and FN shows an effective improvement in the adhesion between the copper metal and Kapton film; in particular, the AN plasma polymer deposition increased the peel strength 4.3 times. Failure occurred mainly in the Kapton film, and the adhesion between the AN plasma polymer and the Kapton film and that between the copper metal and the AN plasma polymer were found to be quite strong.     

Adhesion of polyvinyl alcohol cord,and fabric to special purpose rubbers in the presence of HRH dry-bonding agents

The adhesion of polyvinyl alcohol (PVOH) cord and fabric to different special purpose rubbers has been studied with a view to making use of the textile in various applications such as in gaskets, diaphragms, and other industrial molded goods. Adhesion was measured with both raw and chemically treated cords and fabrics, and in the presence of hydrated silica-resorcinol-hexamethylenetetramine (HRH) dry-bonding agents. The pull adhesion strength of the PVOH cable cord (untreated) to EPDM rubber and polyurethane rubber improved significantly on incorporating HRH dry-bonding agents. However, for chemically treated cords the bond strength improved for EPDM rubber but decreased marginally for polyurethane rubber. The peel adhesion strength of the PVOH fabric (both raw and chemically treated) improved slightly with the introduction of dry-bonding agents for all the rubbers studied except nitrile rubber. The physicomechanical properties and aging characteristics of the rubber vulcanizates in the presence of the dry-bonding agents are reported.     

Effect of bonding systems on the adhesion of butyl rubber to polyester fabric

An adhesion promoter system composed of hexamethylene tetramine, resorcinol, and hydrated silica was compounded with butyl rubber mix. This mix was spread over untreated polyester fabric. The resorcinol was also replaced by o-aminophenol, m-aminophenol, or m-phenylene diamine. The rubber-fabric materials were subjected to aging or exposed to ionizing radiation. The peel strength, permeability, dielectric constant, and electrical resistivity were examined.     

Tantalum and chromium adhesion to polyimide. Part 2. Peel and locus of failure analyses

Ta and Cr adhesion to 3,3'-4,4'-biphenyl tetracarboxylic acid dianhydride-p-phenylenediamine derived (BPDA-PDA) polyimide (PI) surfaces has been studied before treatment, and after CF₄ reactive ion etching (RIE), and Ar sputtering. The initial peel adhesion results for both metals on the BPDA-PDA surfaces are comparable and show increased peel adhesion as a function of the surface treatment in the following order: virgin (no treatment) < Ar sputter < CF₄ RIE ~ CF₄ RIE followed by Ar sputter. The surface roughness effect on metal/PI adhesion has also been investigated. The data suggest that the surface roughness does not primarily affect peel adhesion. In this case, it is the removal of the weak boundary layer and the cracking of the residual PI on the metal peel interface surface during the peeling process which cause the increase in the peel strength. It is also proposed that the changes observed in the peel strength as a function of the surface treatment are due to differences in the fracture toughness of the modified PI layers rather than differences in the surface roughness.     

Use of the Blister Test to Study the Adhesion of Brittle Materials. Part II. Application

Using a modified form of the blister test, where the adhesive layer was between the substrate and a massive base, instead of as a continuous sheet on top of the substrate, we determined the interfacial fracture energy F for a series of interfaces where a brittle material (ice) was adhering to various substrates. Fracture energies obtained were compared with work of adhesion values measured for water on the same substrates. Fracture energy, which contains within it both a reversible contribution due to intermolecular interactions across the interface (work of adhesion) and an irreversible contribution due to collective dissipative processes, was found to rise rapidly with modest increases in work of adhesion. The observed relation suggests that the irreversible contribution to fracture energy is influenced strongly by the intermolecular interactions at the interface.     

Use of the Blister Test to Study the Adhesion of Brittle Materials. Part II. Application

Using a modified form of the blister test, where the adhesive layer was between the substrate and a massive base, instead of as a continuous sheet on top of the substrate, we determined the interfacial fracture energy F for a series of interfaces where a brittle material (ice) was adhering to various substrates. Fracture energies obtained were compared with work of adhesion values measured for water on the same substrates. Fracture energy, which contains within it both a reversible contribution due to intermolecular interactions across the interface (work of adhesion) and an irreversible contribution due to collective dissipative processes, was found to rise rapidly with modest increases in work of adhesion. The observed relation suggests that the irreversible contribution to fracture energy is influenced strongly by the intermolecular interactions at the interface.     

A molecular mechanics approach to the adhesion of urea-formaldehyde resins to cellulose. Part 2. Amorphous vs. crystalline Cellulose I

The average adhesion of urea-formaldehyde (UF) resins to amorphous cellulose appears to be lower than that to crystalline Cellulose I. Water appears to be able to displace UF resins on many sites of amorphous cellulose. Selected high attraction sites appear to still be able to give adequate adhesion. There are indications that UF resins' wetting of amorphous cellulose is independent of the resin water content. The energies of interaction of UF oligomers with amorphous cellulose and Cellulose I help in distinguishing between adhesion of UF resins of different stages of condensation. It is also shown that the molecular mechanics method outlined in this article can be used to scan UF adhesive formulations as regards resin adhesion to lignocellulosic substrates.     

Oxidation of Aqueous Sulphur Dioxide Catalysed by Poly-4-vinylpyridine–Cu(II) Complex. Part 2: Combined Homogeneous and Heterogeneous Phase Oxidation

Aqueous phase oxidation of sulphur dioxide at low concentrations catalysed by a PVP–Cu complex in the solid phase and dissolved Cu(II) in the liquid phase is studied in a rotating catalyst basket reactor (RCBR). The equilibrium adsorption of Cu(II) and S(VI) on PVP particles is found to be of the Langmuir-type. The diffusional effects of S(IV) species in PVP–Cu resin are found to be insignificant whereas that of product S(VI) are found to be significant. The intraparticle diffusivity of S(VI) is obtained from independent tracer experiments. In the oxidation reaction HSO₃⁻ is the reactive species. Both the S(IV) species in the solution, namely SO₂(aq) and HSO₃⁻, get adsorbed onto the active PVP–Cu sites of the catalyst, but only HSO₃⁻ undergoes oxidation. A kinetic mechanism is proposed based on this feature which shows that SO₂(aq) has a deactivating effect on the catalyst. A rate model is developed for the three-phase reaction system incorporating these factors along with the effect of concentration of H₂SO₄ on the solubility of SO₂ in the dilute aqueous solutions of Cu(II). Transient oxidation experiments are conducted at different conditions of concentration of SO₂ and O₂ in the gas phase and catalyst concentration, and the rate parameters are estimated from the data. The observed and calculated profiles are in very good agreement. This confirms the deactivating effect of non-reactive SO₂(aq) on the heterogeneous catalysis. © 1997 SCI.     

A molecular mechanics approach to the adhesion of urea-formaldehyde resins to cellulose. Part 1. Crystalline Cellulose I

The energies of interaction of urea, methylol ureas, and urea-formaldehyde (UF) condensates, methylolated and non-methylolated, linear and branched, up to trimers, with the surfaces of an elementary model of the crystal of Cellulose I were obtained by molecular mechanics techniques. The results indicated, firstly, that methylolation enhances adhesion, especially at low molecular weights, while branching tends to decrease it; secondly, that adhesion of UF resins to the cellulose surface can be enhanced by shifting the resin preparation conditions to increase the proportion of species having higher specific adhesion. The theoretical results obtained are in agreement with published experimental evidence. While urea resins show stronger average affinity for cellulose than the average affinity of water, this trend is less marked than in phenol-formaldehyde (PF) resins. The results obtained also appear to infer that the lack of water resistance of UF resins is mainly due to the instability in water of the internal, covalent, aminoplastic bond rather than to UF adhesion to cellulosic substrates. Resin-substrate H-bonding was shown to be of lesser importance in UF than in PF resins.     

The conversion of polysaccharides to hydrogen gas. Part II: The catalytic decomposition of formaldehyde in the aqueous phase

The aqueous phase decomposition of formaldehyde, to hydrogen gas, catalysed by platinum—copper chromite, has been carried out in the temperature range 20–60°C, at a solution pH of 12. The production of hydrogen was favoured by intermediate temperatures (40–50°C) and an activation energy of 22.2 kJ mol^?1 (5.3 kcal mol^?1) was recorded. The rate of reaction was first order with respect to OH^? ion concentration at low alkali concentrations and was first order with respect to HCHO concentration at all concentrations. At high alkali concentrations the reaction should become zero order with respect to OH^? ion concentration, but initial rates actually decrease under these conditions having passed through a maximum. The rate of reaction was directly proportional to catalyst weight at low catalyst loading, but the relationship became non-linear at high catalyst loadings. Conversions of formaldehyde to hydrogen gas were substantially less than theoretical. The decomposition reaction has to compete with a number of side reactions such as polymerization of formaldehyde at low temperatures (<40°C) and at higher temperatures with the Cannizzano reaction, aldol condensation, and possibly formaldehyde hydrogenation to methanol. In addition hydrogen loss may occur due to copper chromite reduction. A reaction mechanism is proposed involving a surface formate intermediate.