Acetone Cleaning Research Articles

Preparation and properties of polyester fibers with polyacrylamide hydrogel grafted by UV‐irradiation

AbstractIt is widely recognized that polyester (PET) fibers with swelling properties are necessary for advanced applications of PET fibers in waterproof fabrics. This study presented the UV‐initiated methods to graft polyacrylamide (PAM) hydrogel on the surface of PET fibers. In the one‐step method, PET fibers are impregnated with a mixed solution of the photoinitiator benzophenone (BP) and the monomer acrylalkylamine (AM). Then, the PET fiber was directly exposed to UV light. In the two‐step method, PET fibers were first impregnated with a photoinitiator solution to generate BP radicals. Then, the fibers impregnated with a monomer solution before being grafted by UV light. Both two methods ultimately achieve PAM gelation‐modified PET fibers. The chemical composition and surface structure were detected by Fourier transform infrared spectroscopy and scanning electron microscope. The findings demonstrate that the PAM hydrogel was successfully grafted on the PET fibers through one‐step method or a two‐step method. In addition, the properties of the grafted PET fibers were evaluated by grafting yield, contact angle, and swelling test. The study indicated that the modified PET fibers via a two‐step method exhibited a superior grafting yield up to 29.3% (PET‐2n) and 54% (PET‐2) compared to the one‐step technique (PET‐1). It was shown that the grafting efficacy of PET fibers modified by two‐step method is better than one‐step method. The static contact angles of PET fibers by UV‐Induced were all reduced. For instance, the contact angles of PET‐2n were decreased from 115° to 62.9°; and the two‐step modified PET fiber after acetone cleaning (PET‐2) decreased from 115° to 60°. It was suggested that the hydrophilicity of the modified PET fibers significantly increased. In addition, the research shows that the gelation‐modified fibers were all possessed swelling properties.

Surface treatment on metal foam wick of a ferrofluid heat pipe

In this current investigation, two metal foams (stainless steel) were treated and cleaned to be modified into superhydrophilic and superhydrophobic surfaces. The surface modifications of the metal foams were prepared using acetone cleaning and superhydrophobic coating methods. The two metal foam samples were then characterized to analyze the morphology, physical properties, wettability and capillary. The superhydrophilic metal foam was chosen as the wick structure in cylindrical heat pipe because of high wettability, and capillary behavior as characterized previously. In the cylindrical heat pipe, ferrofluid was used as the working liquid. The cylindrical heat pipe was tested at two heat input variations of 3 and 5 W in a horizontal direction. The heat pipe's performance test proposed that the optimum thermal resistance is 2.47 °C/W at a heat input of 5 W.

Effect of CFRP surface topography on the adhesion and strength of composite-composite and composite-metal joints

Manufacturing carbon-fibre reinforced polymer (CFRP) composites via different techniques often leads to contrasting surface topographies. Such differences can affect any subsequent surface pre-treatments that are performed and these can ultimately affect joint strength. In the present work, CFRP adherends made using compression moulding or autoclaving were investigated. Pre-treatment techniques of acetone cleaning, plasma treatment, and grit blasting were studied. It was found that the patterned surfaces which had resulted from the vacuum autoclave moulding resulted in improved joint performance when CFRP substrates were bonded together (homogeneous bonding) compared to joints formed with flatter surfaces following compression moulding. However, when CFRP substrates were bonded to flat aluminium alloy substrates (hybrid bonding) the patterned surfaces resulted in inferior joint performance compared to the flatter CFRP substrates. It is proposed that the dissimilarity of surface topographies on the metal and composite substrates negatively influences the strength of the joint.

Surface engineering of carbon fibre/epoxy composites with woven steel mesh for adhesion strength enhancement

Effects of surface modifications on the adhesive joint of carbon fibre reinforced polymer (CFRP) were investigated. CFRP surfaces were treated with traditional methods, such as acetone cleaning, sanding, grit blasting and peel ply. As a novel type of surface modification, stainless steel 316 wire mesh was co-cured on the CFRP laminate during the manufacturing stage. The surface topography of CFRP adherends was analysed through microscopic imaging. Surface roughness values were measured using a surface roughness tester. Contact angle measurements of probe liquids were performed to calculate surface energy. All adherends were bonded with a low viscosity epoxy adhesive. The single lap shear tests were used to measure the bonding strength of the CFRP joints. The experimental results showed that the highest average shear strength (24.2 MPa) was achieved for metal mesh modified joints. This amounted to a 101.7% increase compared with acetone-cleaned specimens. There was no statistically significant difference in shear strength among joints subjected to traditional surface treatments. Fracture surface images were analysed and correlation between surface treatment and lap shear strength was critically discussed.

Bonding performance of a thiohydantoin-methacrylate monomer on noble metal alloys.

This study assessed the effect of a primer containing 10-methacryloyloxydecyl-(2-thiohydantoin-4-yl)propionate (MDTHP) on the bonding of noble metal alloys to an acrylic resin. Three noble metal alloys were selected as adherends, and V-Primer containing 6-(4-vinylbenzyl-n-propyl)amino-1,3,5-triazine-2,4-dithione was used as a comparative control. The disk specimens of each noble metal alloy were wet-ground and divided into three conditions: specimens primed with MDTHP primer or V-Primer, and specimens without priming. An acrylic resin was bonded to each specimen, and the specimens were performed the shear bond test. The MDTHP primer showed higher shear bond strength than the V-Primer for all specimens. X-ray photoelectron spectroscopic analysis showed that MDTHP was adsorbed on the Au-Pt-Pd alloy surface even after acetone cleaning. MDTHP binds not only with Cu but also with Au and Ag, promoting the bond strength of noble metal alloys. The effectiveness of MDTHP on dental noble metal alloys was suggested.

Ultra-clean high-mobility graphene on technologically relevant substrates.

Graphene grown via chemical vapour deposition (CVD) on copper foil has emerged as a high-quality, scalable material, that can be easily integrated on technologically relevant platforms to develop promising applications in the fields of optoelectronics and photonics. Most of these applications require low-contaminated high-mobility graphene (i.e., approaching 10 000 cm2 V-1 s-1 at room temperature) to reduce device losses and implement compact device design. To date, these mobility values are only obtained when suspending or encapsulating graphene. Here, we demonstrate a rapid, facile, and scalable cleaning process, that yields high-mobility graphene directly on the most common technologically relevant substrate: silicon dioxide on silicon (SiO2/Si). Atomic force microscopy (AFM) and spatially-resolved X-ray photoelectron spectroscopy (XPS) demonstrate that this approach is instrumental to rapidly eliminate most of the polymeric residues which remain on graphene after transfer and fabrication and that have adverse effects on its electrical properties. Raman measurements show a significant reduction of graphene doping and strain. Transport measurements of 50 Hall bars (HBs) yield hole mobility μh up to ∼9000 cm2 V-1 s-1 and electron mobility μe up to ∼8000 cm2 V-1 s-1, with average values μh ∼ 7500 cm2 V-1 s-1 and μe ∼ 6300 cm2 V-1 s-1. The carrier mobility of ultraclean graphene reaches values nearly double than those measured in graphene processed with acetone cleaning, which is the method widely adopted in the field. Notably, these mobility values are obtained over large-scale and without encapsulation, thus paving the way to the adoption of graphene in optoelectronics and photonics.

Comprehensive study on the influence of different pretreatment methods and structural adhesives on the shear strength of hybrid CFRP/aluminum joints

ABSTRACT The aim of this study was to investigate the influence of laser treatments with varying energy density and wavelength on the surface structure, shear strength and fracture behavior of hybrid compounds of thermoset carbon fiber-reinforced polymer (CFRP) and aluminum (Al) bonded with three different structural adhesives. The CFRP was pretreated by laser with near-infrared (NIR) and ultraviolet (UV) wavelengths and applying different energy densities. Aluminum surfaces were structured with NIR. Reference CFRP/Al-specimens were prepared by acetone cleaning, low pressure oxygen/argon plasma or sand blasting. The surfaces were investigated microscopically before bonding and after mechanical testing. In addition, the surfaces were examined with white light interferometer and sessile droplet test methods. The bonded compounds were characterized in standardized single lap shear tests to reveal the influence of the pretreatment strategies on the joint strength. Suitable process windows for laser pretreatments were identified, including NIR-pretreatment methods that can compete with an UV-laser source. For every adhesive, a suitable pretreatment method was found.

Effects of surface modification and graphene nanoplatelet reinforcement on adhesive joint of aluminium alloys

In this study, the combinative effects of surface treatments and the reinforcement of graphene nanoplatelets (GNPs) on the adhesive joint of aluminium alloy were investigated. Aluminium alloy plates were treated with acetone cleaning, grit blasting, chemical etching, and phosphoric acid anodisation (PAA) under various conditions. The effects of hydrothermal sealing of the anodised aluminium were also studied. Surface energies of the treated aluminium plates were determined using contact angle measurements. The samples were then bonded with epoxy or GNPs reinforced epoxy adhesives. The bonding strength of the aluminium joints was measured by single lap shear tests. The joint strength was significantly affected by both surface treatment and the reinforcement of GNPs. For grit blasted and PAA samples with hydrothermal sealing, the joint strength increased by 64% and 57% respectively due to the addition of 0.42 wt% of GNPs. Across all surface treatments, the highest average shear strength (17.6 MPa) was achieved for PAA samples with hydrothermal sealing and the addition of GNPs followed by PAA samples with no sealing and pure epoxy (17.0 MPa). Fractal surface images were analysed, and the correlation between epoxy infiltration behaviour, surface treatments and nano-reinforcement was critically discussed.

The Effect of Air Exposure on SEY and Surface Composition of Laser Treated Copper Applied in Accelerators

In this paper, the effect of air exposure and acetone cleaning on the secondary electron yield (SEY) of laser treated copper were investigated and discussed. The SEY of laser treated copper samples after acetone cleaning and air exposure were measured. After 10 to 21 months air exposure, the maximum SEY increased by about 11%~20%. Furthermore, changes of carbon, copper, and oxygen chemistry states from sample surface after acetone and air exposure were studied by means of XPS. The XPS results show that the concentration of Cu decreased by about 61%~70% after acetone cleaning and decreased by a further 36%~70% after 10 to 21 months air exposure. Moreover, the XPS measurement reflects the significant increase of the total percentages of C and O after acetone cleaning, and further increase after 10 to 21 months air exposure. The increase of SEY is explained in terms of the introduction of impurities, such as oxide, carbide etc.

Using the 3-point bending method to study failure initiation in epoxide-aluminum joints

The increasing use of adhesives in industry has boosted the search for tests which allow the adherence level to be defined. These tests, depending on the type of load, examine different stresses, failure modes and mixed modes. Furthermore, these tests can be focused either on initiation or propagation of adhesive failure. The subject of this study is the initiation of adhesive failure. The initiation of failure can be determined with the 3-point bending test. Trials of 3-point bending tests were conducted on an aluminum 2024 substrate, with two different thicknesses, in order to understand the impact of the adherend thickness. The aluminum substrate received different types of surface pre-treatment: acetone cleaning, hydrochloric acid etching or aminopropyltriethoxysilane coating. Two adhesives were used: the first one was a mixture of epoxy pre-polymer DGEBA and DETA amine, whereas the second was a commercially formulated adhesive, ELECOLIT 6604. The initiation of adhesive failure was obtained by 3-point bending test and verified with SEM analysis. The failure loads measured enabled the effect of surface treatment on adhesive failure to be revealed: the results indicate that the surface treatment with silane is the most efficient in comparison to hydrochloric acid etching and of course to the simple acetone degreasing. It was assumed that the scatter of the results obtained for each series is due to the variation of the “intrinsic” adherence between the adhesive and the substrate. Furthermore, it was noted that the failure loads for different substrate thicknesses cannot be compared due to the effect of the thickness: it was therefore not possible to simply compare results obtained for different thicknesses of the same substrate for a given substrate-adhesive system. The energy approach proposed in this study makes it possible. The energy requested to initiate the adhesive failure for a given system can then be known, whatever the initial geometry of the 3-point bending test is. However, it was also shown that the thickness of the substrate must be correctly chosen. A thick substrate increases the dispersion and a thin substrate may induce local unwelcome plastic strain. In conclusion, this study allows to define an energy criteria for adhesives failure initiation.

Influence of Polymer Residues on the Double Resonance Process of Bilayer Graphene

PMMA is commonly used for graphene transfer and device processing. However, it leaves a thin layer of polymer residues after standard acetone cleaning and causes electrical and thermal performance degradation of graphene devices. In this paper, we present a research of the impact of polymer residues on surface morphologies and electronic properties of bilayer graphene using Raman spectroscopy in combination with atomic force microscopy (AFM). The electronic structure of bilayer graphene is well captured in its Raman spectrum, of which the 2D band reveals four double resonance Raman scattering processes. The Raman analyses show universal blueshifts of the G band and the four 2D sub-bands P11, P12, P21, P22, as well as reduced intensity ratios of the sub-bands to the G band I(Pij)/I(G) after surface contamination by polymer residues, implying an electronic structure modulation in bilayer graphene. The effects are mainly attributed to p-type doping and extrinsic scattering induced by residual impurities and defects.

Contact Angle Analysis on Glass Based Surface

This paper reports on the contact angle measurement analysis on a glass based surface for anodic bonding process cleaned by three distinct cleaning processes. The three types of glass based surface used were silica, pyrex, and soda lime glass. The three cleaning solutions tested in this experiment were RCA, piranha and acetone. Water Droplet Test (WDT) was done to analyze the contact angle of micro droplet on sample surface. It can be done by dropping a droplet of water in constant volume at the fixed height and angle. Only RCA process constantly decreases the contact angle value after cleaning. The compilations of data strongly proved that all samples become hydrophilic after RCA cleaning process. The solid surface is considered hydrophilic when water contact angle is smaller than 90°, and hydrophobic profile if the water contact angle is larger than 90°. Samples which undergo piranha and acetone cleaning did not prove any characteristic of hydrophilic or hydrophobic surface after cleaning.

Hydrophilicity Characterization on Cleaned Bonded Silicon Based Surface

This paper reports on the contact angle measurement analysis on a silicon based surface for anodic bonding process cleaned by three distinct cleaning processes. The three cleaning solutions tested in this experiment were RCA, piranha and acetone. Water Droplet Test (WDT) was done to analyze the contact angle of micro droplet on sample surface. It can be done by dropping a droplet of water in constant volume at the fixed height and angle. Only RCA process constantly decreases the contact angle value after cleaning. The compilations of data strongly proved that all samples become hydrophilic after RCA cleaning process. Samples which undergo piranha and acetone cleaning did not prove any characteristic of hydrophilic or hydrophobic surface after cleaning.

Study on Lithium Niobate Wafer Bonding and Thinning

LN is a kind of pyroelectric material. It can be made into a sensitive layer belonging to photoelectric detector’s sensitive element. Usually, the thickness of LN wafer is 0.5mm and that is beyond the requirement for thickness of photoelectric sensitive element. Due to that, LN wafer must be disposed of by bonding, thinning and polishing process. The process mainly contain RZJ-304 photoresist bonding, grinding, polishing, stripping liquid stripping and acetone cleaning. After processed, the dimension of LN wafer is 10mm×10mm×50um. The surface of LN is very smooth, and the surface roughness is 1.63nm.The test shows that the disposed wafer’s peak value of pyroelectric signal is four times as much as that of undisposed one.

Observation of triboelectron emission from real copper surfaces in sliding contact with polytetrafluoroethylene and polyimide

We report the triboelectron emission (TriboEE) behaviors for copper surfaces in sliding contact with polytetrafluoroethylene and polyimide in relation to the XPS analysis. The TriboEE was measured using a gas-flow Geiger counter. The metal surfaces were subjected to the pretreatments of acetone cleaning, mechanical scratching and oxidizing. It was found that there is interdependence between the TriboEE intensity and the XPS elemental intensity. The formation of empty trapping sites on the polymer surface during the sliding process, which can accept the electrons transferred from the metal substrate, is shown to be a substantial process for the TriboEE to retain.

Effects of welding parameters and surface pretreatments on resistance spot welding of AZ31B Mg alloy

The resistance spot weldability of AZ31B magnesium alloy using AC (alternating current) was investigated in this paper. The surfaces of sheet coupons were prepared by acetone cleaning (as-received) and some coupons were also cleaned with chromic acid (H2Cr2O7) after acetone cleaning (acid-cleaned). The surfaces of the as-received AZ31B sheets consisted of MgO, Mg(OH)2, and MgCO3. The extent and thickness of the surface oxide/reaction layer of the sheets varied according to the fabrication process of the sheets, and resulted in different contact resistance. Effects of welding current and weld time were investigated while the electrode force was kept constant. The results indicated that the as-received sheets produced expulsion both at the faying surface and at the work piece/electrode interface due to high contact resistance. Diluted chromic acid cleaning reduced contact resistance and produced good weld quality. Increasing the welding current and weld time enhanced not only the nugget size and joint strength, but also increased indentation on the weld surfaces. A weld lobe was established considering the minimum joint strength, weld expulsion, and surface indentation based on a relevant American Welding Society Standard.

Analysis of manufacturing parameters on the shear strength of aluminium adhesive single-lap joints

An experimental and numerical investigation into the shear strength behaviour of aluminium alloy adhesive lap joints was carried out in order to understand the effect of geometrical and manufacturing parameters on the strength of adhesive bonding joints, with the aim of optimizing shear strength. The adherend material used for the experimental tests was an aluminium alloy in the form of thin sheets, and the adhesive used was a high strength epoxy. Five surface treatments were studied. The surface treatments process using sodium dichromate–sulphuric acid etch (CSA) and abrasive polishing (AP) resulted in improved joint shear strength when compared to acetone cleaning (SW), caustic etch (CE), and Tucker's reagent etch (TR). The decrease in surface roughness was found to increase the shear strength of single-lap joints. An increase in adherend thickness and overlap length was found to increase shear strength which means that an increase in joint rigidity increases its strength. A numerical analysis was developed to explain the effect of the geometrical parameters on rotation angle, stress and strain fields, and failure load. An increase in adherend thickness and overlap length decreases the joint rotation angle, reducing the plastic strain peak and therefore increasing the failure load.

Release Properties and Durability of Release Layer on UV Nanoimprint Lithography

Two photo-curable resins (PAK-01 and PAK-02) have been evaluated by a primitive test and a precise test. The primitive test is simple manual transfer process and the precise test is using UV nanoimprint lithography (UV-NIL) machine. At first, nano order high aspect ratio glassy carbon (GC) molds are prepared and then manual transfers are carried out. Both PAK-01 and PAK-02 have good filling and release properties. Next, a silane coupling agent C8F17C2H4SiCl3 is used for the release treatment of the quartz mold. To investigate of affinity between photo-curable resin and release layer, repetition manual transfers are carried out. In this release layer, durability is not sufficient for PAK-02. Therefore, more precise durability tests are carried out using PAK-01. The release treatment samples with various contact angles are prepared by changing the treatment of the silane coupling agent. The contact angle of less than 10 degrees is obtained by UV ozonation cleaning. The contact angle of 40 degrees is obtained by acetone cleaning. The contact angles of more than 80 degrees are obtained by silane coupling agent at 5 minutes treatment. The contact angles of more than 100 degrees are obtained by silane coupling agent at 2 hours treatment. After the preparation of the mold treatment, repeatedly imprints are carried out using UV-NIL machine. In the case of contact angles with less than 40 degrees, PAK-01 sticks to the surface of the quartz within several imprint times. On the other hand, in the case of contact angles with more than 80 degrees, PAK-01 does not stick on quartz surface more than 1000 times. Therefore, the combination of this release treatment and PAK-01 is suitable for mass-production.

An efficient protein preparation for proteomic analysis of developing cotton fibers by 2-DE

Preparation of high-quality proteins from cotton fiber tissues is difficult due to high endogenous levels of polysaccharides, polyphenols, and other interfering compounds. To establish a routine procedure for the application of proteomic analysis to cotton fiber tissues, a new protocol for protein extraction was developed by optimizing a phenol extraction method combined with methanol/ammonium acetate precipitation. The protein extraction for 2-DE was remarkably improved by the combination of chemically and physically modified processes including polyvinylpolypyrrolidone (PVPP) addition, acetone cleaning, and SDS replacement. The protocol gave a higher protein yield and vastly greater resolution and spot intensity. The efficiency of this protocol and its feasibility in fiber proteomic study were demonstrated by comparison of the cotton fiber proteomes at two growth stages. Furthermore, ten protein spots changed significantly were identified by MS/tandem MS and their potential relationships to fiber development were discussed. To the best of our knowledge, this is the first time that a protocol for protein extraction from cotton fiber tissues appears to give satisfactory and reproductive 2-D protein profiles. The protocol is expected to accelerate the process of the proteomic study of cotton fibers and also to be applicable to other recalcitrant plant tissues.

Surface energetics of cementitious materials and their wettability by an epoxy adhesive

The surface thermodynamic properties of cementitious materials and the wettability of these substrates by an epoxy adhesive were investigated using various surface analysis techniques. In a first step, surface energies of hardened cement pastes were assessed either by contact angle measurements using the Owens and Wendt approach, or by inverse gas chromatography (IGC). A good correspondence was found between the two techniques for the dispersion contribution γ s d , and a strong amphoteric behavior of these materials was also demonstrated. Additionally, a surface carbonaceous contamination detected by X-ray photoelectron spectroscopy (XPS) was found to lower the surface energy of as-received samples, whereas an acetone cleaning treatment resulted in increased γ s d values. In a second part, surface characterizations were performed on three synthetic compounds, representative of the main hydration products of hardened cement pastes, i.e. calcium hydroxide, ettringite and calcium silicate hydrate (C -S -H). IGC experiments provided γ s d values ranging from 45.6 up to 96.3 mJ m −2 at 35 °C, and the acid–base behavior was correlated to the water content. Last, XPS and IGC analyses were performed on cement paste powders coated either with an epoxy resin (R) or with an amine hardener (H), separately, at mass loadings up to 10 wt.%. Changes in the dispersion contribution to the surface energy ( γ s d ) and Lewis acid–base interaction energy were found to be significantly dependent on the adsorption of both H and R, showing a substantial wetting of the mineral substrate by the adhesive components. In addition, XPS evidenced interfacial hydrogen bonding between the hardener and the cementitious substrates.