Effect Of Atmospheric Plasma Treatment Research Articles

Enhancing biodegradable polymer surface wettability properties through atmospheric plasma treatmsurfaent and nanocellulose incorporation

This study investigates the effects of atmospheric plasma treatment on the surface properties of polylactic acid (PLA)/nanocrystalline cellulose (CNC) composites, aiming to improve their wettability and mechanical properties. The research utilizes a twin-screw extrusion process for fabricating PLA/CNC biocomposites, followed by surface modification using a custom-built, with a tenfold high-voltage atmospheric plasma system. The motivation of this treatment was to improved surface wettability and potential for enhanced adhesive bonding in ecological applications. These findings contribute to developing more sustainable composite materials by providing a method to improve the functionality of biodegradable polymers without compromising their environmental benefits.

Effect of atmospheric plasma treatment and wet blast on adhesion characteristics of carbon fiber reinforced LM-PAEK thermoplastic composites

Surface characteristics of polymeric materials are quite challenging for adhesion especially thermoplastics, requiring specific surface preparation operations before reaching successful bonding. These processes are principally aimed to increase the low surface energy of the material, bonding agent contact area and wetting characteristics to provide proper and strong adhesion. In this study, two different surface treatments with different processing parameters were applied to CF/LM-PAEK thermoplastic composites in order to examine the changes on surface characteristics and adhesion strengths. Apart from desired surface treatments for thermoplastics indicated in previous studies and backgrounds, wet blasting method is used to prepare surfaces before bonding. Separately prepared surfaces, applying wet blasting and atmospheric plasma treatment, were adhered using epoxy-based film adhesive to be subjected to single lap shear testing to examine adhesion strength under tensile loading. According to the results of experimental study, it was observed that both surface treatments increased the adhesion strength of the bonded pre-consolidated CF/LM-PAEK thermoplastic composites compared to specimens having untreated surfaces.Atmospheric plasma treatment increased the surface energy by 18.24% and showed higher strength up to 14.93% compared to the untreated specimens. On the other hand, surprisingly, wet blasted specimens with lower surface energies showed high strength up to 6.48% compared to the untreated specimens. In addition to surface energies and lap shear strengths, roughness measurements and SEM surface evaluations were also issued to enlighten obtained test results accordingly.

Effect of atmospheric plasma treatment on Mode-I and Mode-II fracture toughness properties of adhesively bonded carbon fiber/PEKK composite joints

This study aims to assess the influence of peel-ply (PP), mechanical abrasion (MA), and atmospheric plasma activation (APA) treatments on Mode-I and Mode-II fracture toughness of carbon fiber/ poly-ether-ketone-ketone (CF/PEKK) composite joints. A comprehensive examination of the topography and wettability of the adherend surfaces is conducted using various methods. The CF/PEKK adherends are produced through an automated fiber placement (AFP) process, and the CF/PEKK bonded joints are prepared using two different structural adhesive films, one of which has a lower strength, while the other has a higher strength. To evaluate their fracture toughness properties, double cantilever beam (DCB) and end-notched flexure (ENF) tests are carried out in accordance with ASTM standards. Acoustic emission sensors are used to monitor the test specimens during DCB tests, allowing for an in-depth evaluation of the failure modes and damage propagations in the joints. The results show that the GIC and GIIC values of the APA-treated CF/PEKK bonded joints are remarkably higher than those of the untreated ones, with a range of improvement of 34.0–84.8 times and 7.5–17.4 times, respectively. Adhesive failure is the dominant failure mode on the surfaces of non-treated (NT) and PP samples, while cohesive failure is more prominent in those treated with MA and APA. The failure modes of the treated samples varied depending on the adhesive used, with APA-treated samples always exhibiting a cohesive failure. It is observed that the AE counts increase more slowly in APA-treated samples compared to MA-treated joints as delamination progresses more slowly with cohesive failure dominant, which leads to a lower release of AE energy.

Investigation of the Effect of Atmospheric Plasma Treatment in Nanofiber and Nanocomposite Membranes for Piezoelectric Applications

In this work, we report the effect of steady-state atmospheric plasma (Corona discharge) in nanofibers and nanocomposite membranes for piezoelectric applications. The investigation was performed in PVDF (Poly vinylidene fluoride) nanofibers, CNT (Carbon Nanotubes)-reinforced PVDF nanocomposites, and PAN (Poly acrylonitrile) nanofiber membranes. Steady-state plasma was generated with a high voltage power source with 1 mA discharge current output and 6 kV discharge voltage, and the gap between tip and the material was maintained to be 1 cm. For the fabrication of nanofibers and nanocomposite membranes, an electrospinning method was used. The electrospinning parameters, such as flow rate and voltage, were optimally tuned for obtaining uniform nanofibers and nanomembranes. Along with the plasma treatment, heat treatment above the glass transition temperature was also conducted on the nanofiber membranes. Using a Scanning Electron Microscope (SEM), the morphology of the nanofibers was observed. X-ray Diffraction (XRD) demonstrated the polycrystallinity of the nanofibers. Fourier Transform Infrared Spectroscopy (FTIR) analysis of the PVDF nanofibers shows a peak at 796 cm-1 representing α-phase (C-H rocking) in the control sample which is absent in the treated samples. Raman spectroscopy of PVDF nanofibers identifies a Raman shift from 873 cm-1 to 877 cm-1 (denoting β-phase) for plasma-treated samples only. Electron Paramagnetic Resonance (EPR) concludes that the intensity of the free radicals increases from 1.37 to 1.46 (a.u.) after plasma treatment. Then, sensors were fabricated from the PVDF nanofibers, MWCNT-reinforced PVDF nanofibers, and PAN nanofibers to characterize their piezoelectric properties. The impact test results showed that the atmospheric plasma and heat-treated samples had 86%, 277%, and 92% increases of the d33 value (piezoelectric coefficient) in the case of PVDF nanofibers, MWCNT-reinforced nanofibers, and PAN nanofibers, respectively. It was also observed that the capacitance of the nanofiber membranes has increased due to the plasma treatment.

Effect of atmospheric plasma treatment on the wettability of UHMWPE

The wettability of ultra-high molecular weight polyethylene surfaces was modified by atmospheric plasma treatment controlling exposure time and distance. The two-factor experimental design included treating samples for 0.5 and 1.5 s, placed at 2.0 and 4.0 cm from the plasma. The behavior of wettability was monitored for 90 days via the sessile drop method. Right after treatment, contact angle decreased from 85 to nearly 40 degrees. These changes coincided with an increase in the proportion of the orthorhombic crystalline phase and a reduction in the amorphous phase of the material. Later on, these structural changes were reversed. After 90 days of the plasma treatment, the contact angle was 66 and 73 degrees in samples located 2 and 4 cm away from the plasma, respectively. Although the plasma treatment increased the roughness of the polyethylene surface by 6 nm, it basically retained its mirror finish, except for a few blemishes here and there.

Effects of cold atmospheric plasma treatment on the morphological and optical properties of plasmonic silver nanoparticles

The use of plasma processes in nanomaterial synthesis is limited by a lack of understanding of the effects of plasma treatment on the morphology and other properties. Here, we studied the effects of atmospheric plasma treatment on the morphology and optical properties of Ag nanoparticles. The Ag nanoparticles were deposited on substrates by injecting an aerosol into flowing argon gas and then treated with a low-temperature atmospheric plasma jet. After plasma treatment, the mean Ag nanoparticle diameter reduced to an average of 5 nm, which was accompanied by a blue shift of ∼70 nm in the peak of the surface plasmon resonance; these results are similar to those obtained by thermal treatment at elevated temperatures. The reduction in nanoparticle size is explained by the redox reaction that occurs on the nanoparticle surface, which is evident from the presence of AgO and Ag2O Raman peaks in the treated sample. The surface charge changed as a result of plasma treatment, as indicated by a large change in the zeta potential from +25.1 ± 4 mV for the untreated sample to −25.9 ± 6 mV after 15 min of plasma treatment. Surface-enhanced Raman spectroscopy of the plasma-treated films was carried out with the fluorescent dye Rhodamine 6 G, which showed a ∼120-fold enhancement in the signal intensity relative to the untreated substrates. We, therefore, conclude that cold-plasma treatment modified the surface morphology of the Ag nanoparticles, thereby enhancing their optical properties. This technique could be applied to a wide range of nanoparticle systems used in biosensing applications.

The effect of atmospheric plasma treatment of recycled carbon fiber at different plasma powers on recycled carbon fiber and its polypropylene composites

ABSTRACTTo increase the mechanical properties of recycled carbon fiber‐reinforced polypropylene (PP) composites, recycled carbon fibers (RCF) were subjected to atmospheric plasma treatment at different plasma powers (100, 200, and 300 W). The changes on surface topography and roughness of RCF were examined by atomic force microscopy. Plasma treatment of RCF increased the roughness value of RCF. The variation of surface elemental compositions and tensile strength of RCF were determined by using X‐ray photoelectron spectroscopy and tensile test, respectively. Plasma‐treated RCF‐reinforced PP composites were fabricated using high speed thermo‐kinetic mixer. Plasma treatment of RCF at 100 W increased the tensile and flexural strength values of RCF‐reinforced PP composites considerably by 17 and 11%, respectively. However, plasma treatment of RCF at higher plasma powers (200 W and 300 W) decreased tensile and flexural strength values of composites because of the etching of RCF. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47131.

Effect of atmospheric plasma treatment on seed germination of rice (Oryza sativa L.)

Multiple methods of improving plant development have been utilized over the past decades. Despite these improvements, there still exists a need for better planting methods due to the increasing population of a global community. Studies have reported that plasma treatment affects the growth and germination of a variety of plant species, including a multitude of grains which often takes the bulk in the diet of the average human being. This study explores the effect of atmospheric air plasma jet treatment on the seed germination of rice (Oryza sativa L.). The seeds were treated using an atmospheric air plasma jet for 1, 2, and 3 s. The effect of plasma exposure shows a reduction of trichomes on the surface of the seed. This caused a possible increase in wettability which significantly affected the seed germ length but did not affect the seed germination count after the germination period of 72 h.

Effects of atmospheric plasma treatment on adhesion and tribology of aromatic thermoplastic polymers

After cold plasma treatment of poly(ethylene terephthalate) and poly(ether‐ether ketone) surfaces by dielectric barrier discharge (DBD) under atmospheric (air) conditions, variations in surface chemistry, and morphology were investigated in relation with adhesion and tribological properties. According to XPS measurements, surface oxidation caused the formation of low molecular weight moieties of carboxylic acids. The latter resulted in more hydrophilic surfaces according to water contact angle measurements, with mainly a higher polar surface energy component. In parallel, the surface roughness of originally polished surfaces reduced due to flattening of local surface asperities after DBD. The DBD significantly improved the adhesive shear strength for different glue types in polymer/polymer and polymer/steel joints, while the best adhesion was observed for a two‐component epoxy type adhesive. Under dry sliding conditions, the coefficients of friction were lower after DBD compared to pristine samples only under mild sliding conditions (v = 0.05 m/s; p < 1 MPa.m/s), while the higher normal loads caused an increase in coefficients of friction likely due to the higher contributions of surface deformation. Most interestingly, the lower coefficients of friction after DBD were observed under oil lubrication and after cleaning the sliding track (“run‐out” condition), due to the better retention of oil at the sliding surface for plasma‐treated polymers. POLYM. ENG. SCI., 58:E93–E103, 2018. © 2017 Society of Plastics Engineers

Effect of Atmospheric Plasma Treatment on Interlayer Formation and Adhesion Strength between Substrate and Coating Layer

Effect of Atmospheric Plasma Treatment on Interlayer Formation and Adhesion Strength between Substrate and Coating Layer

Mechanical enhancement of graphite nanoplatelet composites: Effect of matrix material on the atmospheric plasma-treated GnP reinforcement

Graphite nanoplatelets (GnPs) are currently employed to manufacture a new class of carbon nanomaterial composites with unique electrical and thermal as well as mechanical properties. However, due to their unreactive graphitic structure, surface activation of GnPs is critical to promote bonding to the matrix material. In a previous study, the effect of atmospheric plasma treatment (APT) on the mechanical performance of GnP epoxy composites was evaluated where the GnP surface activation resulted in a significant increase in composite strength. The current investigation evaluates the effect of GnP plasma activation when using a polycyanurate (PCN) resin as the matrix material. GnPs (5, 25 microns in particle size) were surface treated as a function of plasma exposure durations and then used to manufacture composites. Flexural strengths of these plasma-treated PCN composites increased by 25%, for both the 0.5 wt.% loaded M25 and M5 composite systems. The higher loaded systems (1.0 wt.%) exhibited smaller increases in strength (11%) with APT, due to increased particle-to-particle interactions. The glass transition temperature (Tg) of surface-treated GnP PCN composites exhibited little variation with APT, which was in sharp contrast to APT-treated GnP epoxy composites that exhibited Tg increase up to 20℃. This suggests that the oxygen functional groups formed on the surface of GnPs are less chemically reactive toward the PCN than epoxy resins, translating to relatively limited composite strength improvements when utilizing oxygen APT-treated GnPs in PCN matrices.

The effect of atmospheric plasma treatment of dental zirconia ceramics on the contact angle of water

The purpose of this study was to investigate the effect of atmospheric pressure plasma application on the water contact angle (CA) of zirconia ceramics. Two zirconia ceramics (Katana, Kuraray Noritake Dental and Lava, 3 M ESPE) were used to test the plasma treatment (SAP, surface) with argon gas for one minute (1 L/min). To measure the CA, a drop of water was placed on a zirconia surface, which was observed under optical microscopy, and images were used to calculate the CA (n = 5). The dynamic behavior of the surface wettability was analyzed by collecting the CA data over a 70-hour period. CA data were analyzed by two-way ANOVA and the Tukey test (5%). The CA baseline values were 66° and 68° for Katana and Lava, respectively. After the application of plasma, the CA was reduced significantly to 36° and 31°, respectively. The CAs for Lava zirconia and Katana returned to baseline values after 5 and 15 hours, respectively. The plasma treatment improved the wettability of the zirconia surface, decreasing the CA approximately 50%. The duration of the effect of plasma on zirconia surfaces was at least 5 hours and material-dependent.

The effect of atmospheric plasma treatments on plastic scintillator for beta-ray measurement

A plastic scintillator (PS) can be used for beta-ray measurements using a liquid scintillation counter (LSC) without the necessity for a liquid scintillator when liquid samples of beta-emitters are placed on the PS. However, the measurement efficiency with the PS in this study was not high, especially in the case of tritium. With a sample of tritiated water, a long measurement time was necessary with a conventional LSC. However, the measurement efficiency was improved drastically by modifying the PS surface with atmospheric-pressure glow-plasma processing (the plasma method). A 2 Bq, 20 μL sample of tritiated water placed between two PS sheets was successfully measured within 2 min by an LSC. The measurement efficiency was same as that of using liquid scintillator: 48 ± 2 % for tritiated water. The measurement efficiency was initially increasing over time, and after almost 6 h, it plateaued and remained at a constant value for several weeks. Additionally, the measurement efficiency of the plasma-modified PS was identical when it was used soon after the treatment and after being properly stored for 1 week The results show that plasma-modified PS can be used stably after storage in a freezer or a deep freezer. The plasma method is advantageous because it produces little radioactive waste fluid. This paper presents these results and the results of an investigation of the surface of the plasma-modified PS under observation with an atomic force microscope, and the mechanism behind the high measurement efficiency is discussed.

Characterization of atmospheric plasma as a surface preparation process for the bonding of space composite materials

There is a growing interest in the use of atmospheric plasma treatment techniques for the surface preparation of fiber-reinforced composite hardware before bonding. In this article, we will discuss the effects of atmospheric plasma treatment on the chemical and physical properties of two types of composites (cyanate ester and epoxy) and the resultant mechanical properties. Atomic force microscopy and X-ray photoelectron spectroscopy were used to investigate the surface morphology and chemistry of the treated composites and were correlated to lap shear bond strengths. We observed a strong correlation between the increases in lap shear strength with the surface carboxyl concentration of the composite after treatment as verified by X-ray photoelectron spectroscopy. Changes in surface roughness appeared to be secondary in nature. As a result, we have separated the mechanical contributions caused by etching-induced surface roughness from chemical contributions due to formation of specific reactive surface functional groups. The mechanical and chemical mechanisms that govern surface properties and contribute to the observed enhanced bonding will be discussed.

Effects of Atmospheric Plasma Treatment on the Surface Properties of Wood-Plastic Composites

Wood-plastic composites are a group of materials with potential to penetrate markets currently dominated by plastic or wood products. The surface properties of wood-plastic composite materials have been found to be similar to those of polyolefin materials, thereby presenting a challenge to the use of adhesive joining methods. Plasma chemistry can be performed to improve the adhesive properties of polyolefin materials. In this research, the effect of atmospheric plasma treatment on polypropylene and spruce (Picea abies) wood-plastic composite surfaces is investigated by contact angle measurement with sessile drop method and tensile strength tests of glued samples. The plasma treatment is performed on extruded WPC profiles. Confocal Raman microscopy and scanning electron microscopy are used for analysis of the material surface. The results show an increase in the contact angle of plasma treated WPC materials and an improvement in the tensile strength of glued samples following plasma treatment. Observation of the Raman spectrum indicates an increase in polar groups after plasma treatment. Scanning electron microscopy shows changes in the surface of the treated samples, which can be seen as increased porosity, possibly due to etching as a result of the plasma treatment. It is concluded that atmospheric plasma treatment for adhesion improvement of WPC materials can therefore be applied successfully, although it has a mechanical effect on the surface of the material.

A Development of Atmospheric Pressure Plasma Equipment and Its Applications for Treatment of Ag Films Formed from Nano-Particle Ink

We have developed an equipment of atmospheric pressure plasma with two microwave guide antennas, which have a discharge line with 41 slots. The antennas are set against a stage with a heater in a process chamber. A process gas, which is a 1 % H2 gas diluted by Ar gas and its flow rate is 20 standard litter per minute (slm), flows into the micro-wave guide and goes to a process chamber through each slots. A micro-wave is introduced to the micro-wave guide and the atmospheric pressure plasma grows at each slots. We obtained the electron density of 1×1015 cm−3 and the H radical density of 1×10−16 cm−3 at the slot on the condition of a 10 GHz, 1.5 kWatt, pulsed micro-wave with 2.5 pulsed voltage, 4 kHz pulsed frequency, and a duty ratio of 0.16. We applied this system to improve the quality of the spin-coated Ag firm formed from Ag nano-particle ink. This Ag film showed a resistivity of 32 μΩ cm after annealing on the condition of 180 °C for 30 minutes recommended by the maker (The bulk resistivity of Ag is 1.6 μΩ cm). In order to make the annealing time shorter, we studied the effect of atmospheric plasma treatment of Ag film. We obtained the Ag film of the 5.7 μΩ cm resistivity after the atmospheric pressure plasma treatment under 180 °C for 5 min.

Bondability of TC410 composites: the surface analysis and wetting properties of an atmospheric plasma-treated siloxane-modified cyanate ester composite

Atmospheric plasma treatment (APT) has been used on a number of composite systems as an effective surface preparation technique for adhesive bonding. Recently, a new class of siloxane-modified polycyanurate resin systems (TC410) has been developed for use as a matrix material in composites utilized for space applications. The effect of APT on a TC410/M55J fiber composite was evaluated. Contact angle measurements exhibited a sharp reduction in wetting angle with exposure. An increase in the polar surface energy component with treatment coincides with Fourier transform infrared and X-ray photoelectron spectroscopy (XPS) results, which verify the formation of an oxidized carbonate species formed on the composite surface. A solvent rinse removes the majority of the oxidized species and results in an increase in contact angle, due to the removal of a fine ash. XPS and energy-dispersive x-ray spectroscopy verify the distribution of a siloxane component throughout the resin, which was oxidized during APT and forms a silicate. A 24% increase in bond strength was realized after six passes in comparison to abraded specimens. Higher treatment levels resulted in a decrease in strength; however, a solvent rinse of the APT surface gave rise to some recovery in strength due to the removal of the weakly bonded interlayer.

Improvement Fastnesses and Color Strength of Pigment Printed Textile Fabric

This paper focused on the improvement of fastnesses and color strength of pigment printed textile fabrics. To improve fastness and color strength of the polyester fabrics, atmospheric plasma treatment was used. Polyester fabric was treated with argon or air plasma at atmospheric pressure, and plasma pre-treatment effect on the pigment printing was evaluated. A printing paste comprising synthetic thickener, binder, and pigment was applied using a flat screen printing technique. The fabric was then dried and exposed to heat. The cured prints were evaluated for color property, color fastness to washing, and dry/wet rubbing. The effects of atmospheric plasma treatments were evaluated by XPS, SEM and AFM. When the properties of atmospheric plasma treated samples were compared to those of untreated sample, higher K/S values were obtained. Also, the fastness of treated samples increased between ½ and 1 point.

Bonding Optimization on Composite Surfaces using Atmospheric Plasma Treatment

The effect of atmospheric plasma treatment (APT) on the bonding performance of a cyanate ester and an epoxy carbon fiber reinforced composite fabricated with a polyester peel ply was evaluated. A room temperature (RT) cured epoxy, an elevated temperature cured epoxy, and a cyanate ester resin, were used as the bonding adhesives. Only small increases in the carboxyl species concentration were observed for both composite systems as a function of increasing plasma treatment. Lap shear (LS) tests of the bonded composites showed that the APT resulted in a 30% strength improvement for the RT cured epoxy bonded specimens while the cyanate ester composite exhibited negligible increases due to the formation of a highly oxidized, weakly bonded ash. Contact angle measurements indicated that the temperature exposure associated with the curing of the elevated temperature adhesives also reduced the efficacy of APT. Modifications of the bonding surface of these composites by the incorporation of a plasma responsive (PR) layer resulted in significant LS improvements. After incorporating the PR layer, the improvement in adhesive strength was over 225% that of an untreated specimen and approximately 190% that of the equivalently treated unmodified system. Bond strengths correlated with corresponding increases in carboxyl concentrations after APT.

Effect of Atmospheric Plasma Treatment on Pad-dyeing of Natural Dyes on Wool

Plasma treatment is an emerging surface modification technique that alters dye uptake of wool without using chemicals or water for pre-treatment. Padding is an established continuous dyeing technique known for its efficient use of water, time and energy. This study combined these two techniques for colouration of wool fabric using two natural dyes derived from the Acacia plant family. The investigation focused on the effects of plasma treatment and obtaining unique patterning effects. Helium (100%) and a mixture of helium and nitrogen (95%/5%) were used as the plasma gases under atmospheric conditions. Plasma treated wool fabric was padded with the above natural dyes. Copper sulphate and ferrous sulphate were applied on the dyed fabric as mordant yielding neutral shades of beige and grey respectively. Up to a 30% enhancement of dye adsorption on plasma treated wool substrate was observed as compared to untreated sample for both gases used. This higher adsorption indicates the hydrophilic character of the natural dyes used. Key performance parameters such as fastness to washing, rubbing and light were tested and found to be satisfactory. A single process tone-on-tone pattern was achieved by controlling the plasma exposure of treated area. This study concluded that a merger of natural dyes with modern plasma treatment and padding techniques for wool colouration was feasible.