Surface Modification Of Polyethylene Research Articles

Thermomechanical Properties of Ramie Fiber/Degradable Epoxy Resin Composites and Their Performance on Cylinder Inner Lining.

Type IV gas cylinders are widely used in the field of vehicles due to their advantages such as light weight, cleanliness, and low cost. Ramie fiber/degradable epoxy resin composites (RFRDE) provide new ideas for the material selection of Type IV gas cylinders due to their advantages of low carbon emissions, low environmental pollution, and renewable resource utilization. However, the poor interfacial bonding strength and moisture resistance between polyethylene plastics and RFRDE have limited their application areas. This study tested the mechanical properties of ramie fibers at different heat treatment temperatures, and studied the thermal mechanical properties of RFRDE through differential scanning calorimeter and curing kinetics methods. At 180 °C, the tensile strength of fiber bundles decreased by 34% compared to untreated fibers. As the highest curing temperature decreases, the tensile strength of RFRDE increases but the curing degree decreases. At the highest curing temperature of 100 °C, the tensile strength of RFRDE is 296 MPa. The effect of the corona discharge and flexible adhesive on the surface modification of polyethylene was analyzed using scanning electron microscopy. These results provide guidance for the development of natural fiber/degradable epoxy resin composite materials.

Development of an antifungal film by polyethylene surface modification with natamycin

Abstract An antifungal low-cost film for cheese packaging was developed using a tailor-made coating process by direct natamycin (Nat) spraying onto heat softened polyethylene film surface. Two spraying systems Nat/ethanol solution and Nat/n-heptane suspension with the same Nat concentration were explored. To select the adequate system, differences in coating efficiency regarding shape, size, dispersion and distribution of particles, as well as polyethylene film/Nat adhesion and antifungal activity of both modified films were assessed and compared. Besides, the suitability of final product related to its use as food flexible packaging was considered. The results indicate that Nat coating is achieved either by direct particle incorporation (from a suspension) or by its in-situ formation (from a solution). Both kind of Nat coated films have shown antifungal effectiveness against A. niger even after severe extraction treatments. The proposed versatile process is feasible to be industrially scaled and allows to obtain an antifungal film suitable for cheese packaging that can be intensively handled without losing their activity.

Influence of water addition on the modification of polyethylene surface by nitrogen atmospheric pressure plasma jet

ABSTRACTPolyethylene (PE) has many excellent material properties (low density, high flexibility, good chemical resistance, etc.), and is widely used in industrial and medical fields. However, the practical applications of PE are sometimes limited due to its poor wettability. In this article, we employ pure nitrogen atmospheric pressure plasma jet (APPJ) and N2‐H2O APPJ to hydrophilize PE surfaces. Wettability, time stability, chemical composition, micromorphology, and mechanical properties of the treated surfaces are investigated by contact angle measurement, X‐ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, and electric digital display push–pull machine. The pure nitrogen APPJ can hydrophilize PE surfaces without inducing obvious microstructure changes, and relatively better wettability (water contact angle = 13°) could thereby be achieved. On the other hand, the N2‐H2O APPJ creates micro/nanoscale pores on the treated hydrophilic surfaces, contributing to the better time stability and lower tensile strength. The results reported here clearly demonstrate the great potential of nitrogen APPJs with different water mixing ratios in controlling surface wettability and microstructures of polymer surfaces. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47136.

Influence of ethanol vapor addition on the surface modification of polyethylene in a dielectric barrier discharge

In this paper, ethanol vapor up to 50% is added to an argon, air or nitrogen dielectric barrier discharge at medium pressure to profoundly investigate the effect of ethanol addition on the surface modification of low density polyethylene (LDPE). Water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS) measurements show that the ethanol vapor addition effect on the LDPE surface depends on the used carrier gas. Adding ethanol to an argon plasma has no significant effect on the wettability nor on the chemical composition of LDPE compared to a pure argon plasma treatment. Ethanol addition does however slightly increase the LDPE surface roughness. Addition of small amounts of ethanol vapor to an air plasma makes it possible to incorporate additional nitrogen and oxygen groups on the LDPE surface, resulting in an extra decrease of 11% in WCA value. Moreover, the LDPE surface roughness is slightly increased due to the ethanol vapor addition. The most significant effect of ethanol addition is however observed when nitrogen is used as carrier gas. After an N2/2% ethanol plasma treatment, an 85% reduction in WCA value to 8.5° is found compared to a pure N2 plasma treatment. This very hydrophilic LDPE surface is obtained due to a significantly high incorporation of oxygen and nitrogen groups on the surface with an O/C and N/C ratio reaching 32% and 53% respectively. FTIR measurements also reveal that the observed extremely high wettability of LDPE is not the result of plasma activation but is due to plasma polymerization effects occurring on the surface resulting into the deposition of a plasma polymer containing ketones, amides as well as CN groups. In addition, ageing studies have also been conducted and these studies reveal that for all carrier gases, ethanol addition to the discharge gas significantly suppresses the ageing effect. All the above mentioned conclusions therefore indicate that ethanol vapor based plasmas can be an excellent tool to increase the surface energy of polymers.

Surface modification of polyethylene in an argon atmospheric pressure plasma jet

The surface properties of polyethylene can successfully be altered using argon plasmas. In this work, the surface modification of low density polyethylene (LDPE) using an argon atmospheric pressure plasma jet (APPJ) is profoundly investigated. The surface modification is examined using different analysing techniques namely, water contact angle (WCA) measurements for the wettability and X-ray photoelectron spectroscopy (XPS) for the chemical composition. Particular attention is paid to the treatment distance between the plasma jet capillary and the LDPE foil and the applied treatment time. At treatment distances between 5 and 15mm, the WCA can be reduced with more than 70% within a treatment time of a few ms. XPS measurements reveal that this is due to the incorporation of oxygen containing groups and especially the increased implementation of the O–CO group has a big influence. At treatment distances above 15mm, the wettability decreases with increasing treatment distance. The wettability can however be enhanced by increasing the treatment time. Ageing considerations show that the loss in treatment efficiency is restricted to only 25%, meaning that even after 14days of ageing the WCA reduction upon plasma treatment is still more than 40%. Based on the above mentioned results, the most appropriate parameters can thus be selected to provide an efficient plasma treatment of LDPE using the argon APPJ.

Polyethylene Surface Modification by Side Chain Crystalline Block Copolymer

SummaryRecently, we found that Side Chain Crystalline Block Co‐Polymer (SCCBC), which has a long alkane side chain (>C10), can be used as a good dispersant for a concentrated polyethylene fine‐particle dispersion. We also found that the viscosity of this concentrated dispersion increased at high temperature and returned to normal at low temperature. We named this fluid Thermal Rheological Fluid (TR Fluid). The mechanism of this phenomenon involves the attachment and detachment of SCCBC. With the use of this mechanism, we examined whether it could be possible to modify the properties of a polyethylene (PE) surface. A PE film was dipped in a dilute SCCBC solution, and its surface was coated by SCCBC. The water contact angle changed from around 90° before coating to around 70° after coating. Thus, the surface of PE was made more hydrophilic. The adhesion strength was examined by a tensile test. The PE film elongated before the attached region broke. These results showed that SCCBC has a very high adhesion strength and can be used as a surface modifier or primer for attachment. Additionally, SCCBC could be easily removed from the PE film by hot water, and thus, it should be very easy to recycle or re‐use the PE.

Surface activation of polyethylene with an argon atmospheric pressure plasma jet: Influence of applied power and flow rate

Atmospheric pressure plasma technology offers attractive perspectives to alter the surface properties of polymers. Within this context, the surface modification of polyethylene (LDPE) by an argon atmospheric pressure plasma jet (APPJ) is profoundly investigated in this work. The influence of two different parameters (applied power and argon flow rate) on the plasma jet characteristics and the LDPE surface properties is examined in detail. In a first step, the APPJ is electrically and visually characterized and visual inspection of the afterglow clearly shows that mainly a variation in argon flow rate can result in a changing afterglow length. A maximum afterglow length is obtained at an argon flow rate of 1–1.25slm, while higher gas flows result in turbulence leading to a shorter afterglow. Secondly, the surface modification of LDPE is examined using different analyzing techniques namely water contact angle (WCA) measurements for the wettability, X-ray photoelectron spectroscopy (XPS) for the chemical composition and atomic force microscopy (AFM) for the surface morphology determination. WCA measurements show that by increasing the applied power the wettability of the LDPE increases. Increasing the argon flow rate up to 1.25slm gives a decrease in WCA value or in other words an increased wettability. From 1.25slm on, an increase in argon flow rate during plasma treatment decreases the LDPE wettability as can be concluded from the increased WCA values. An increased wettability can be explained by the incorporation of oxygen moieties. By increasing the discharge power, the concentrations of all oxygen containing groups such as CO, CO and OCO increase. Increasing the flow rate up to 1.25slm results mainly in an increase in OCO groups. However, from a flow rate of 1.25slm on, the concentration of all oxygen groups again decreases. Based on these results, the appropriate settings for an efficient plasma treatment can easily be selected.

Influence of Water Vapor Addition on the Surface Modification of Polyethylene in an Argon Dielectric Barrier Discharge

In this paper, water vapor up to 41% is added to an argon dielectric barrier discharge at medium pressure to profoundly investigate the effect of water vapor addition on the surface modification of polyethylene (PE). Contact angle measurements show that the wettability of PE significantly increases after a pure argon plasma treatment. However, the addition of water vapor to the argon feeding gas can give an extra 30% decrease in water contact angle. This extra decrease is due to the incorporation of additional oxygen containing groups such as CO, CO, OCO, and OCO. AFM results reveal that the surface roughness of PE only increases for plasma treatments with no or low water vapor concentrations. All this indicates that a water vapor based plasma can be an excellent tool for the surface activation of PE.

Photochemical modification of polyethylene surface with aryl azides

It has been shown that the formation of a covalently grafted modifying layer takes place during the photolysis of polycrystalline layers of 2-azidoanthraquinone and 4-azidobenzoyl azide on the surface of polyethylene. Its thickness is determined by the amount of the azide applied, and phenyl isocyanate groups formed by the photolysis of 4-azidobenzoyl azide are prone to further functionalization of the modified surface with primary amines.

Nitrogen Plasma Modification and Chemical Derivatization of Polyethylene Surfaces – An In Situ Study Using FTIR‐ATR Spectroscopy

AbstractChemical derivatization reactions of nitrogen plasma‐treated surfaces with aromatic aldehydes, such as the prototypic 4‐trifluoromethyl‐benzaldehyde (TFBA), have for a long time been considered selective for primary amines. Results of an in situ study using FTIR‐ATR spectroscopy challenge the validity of this assumption: Modification of polyethylene surfaces by afterglows of dielectric barrier discharges in nitrogen–hydrogen mixtures with subsequent hydrogen/deuterium exchange or TFBA derivatization suggests that the latter does not follow the commonly assumed reaction scheme.

Mussel- and Diatom-Inspired Silica Coating on Separators Yields Improved Power and Safety in Li-Ion Batteries

In this study, we developed an integrative bioinspired approach that improves the power and safety of Li-ion batteries (LIBs) by the surface modification of polyethylene (PE) separators. The approach involves the synthesis of a diatom-inspired silica layer on the surface of the PE separator, and the adhesion of the silica layer was inspired by mussels. The mussel- and diatom-inspired silica coating increased the electrolyte wettability of the separator, resulting in enhanced power and improved thermal shrinkage, resulting safer LIBs. Furthermore, the overall processes are environmentally friendly and cost-effective. The process described herein is the first example of the use of diatom-inspired silica in practically important energy storage applications. The improved wetting and thermal properties are critical, particularly for large-scale battery applications.

Surface modification of polyethylene by diffuse barrier discharge plasma

AbstractLow‐density polyethylene (LDPE) modified by atmospheric dielectric surface barrier discharge plasma in oxygen was investigated to improve surface properties and adhesion of LDPE to more polar polymers. The process of plasma modification was investigated using several methods—surface energy measurements, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR‐ATR), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The surface energy of LDPE increased significantly after activation by oxygen barrier plasma even at very short time of modification. The FTIR‐ATR spectra manifested the presence of carbonyl functional groups on the surface of polymer pre‐treated by oxygen barrier plasma. It was shown by SEM, and AFM, that the topography of modified LDPE was significantly changed and the surface of modified polymer exhibited higher roughness in comparison with unmodified polymer. The surface energy of treated LDPE diminished in the course of ageing especially during the first 10 days after modification by barrier plasma. Hydrophilicity of the modified LDPE surface was stabilized by photochemical post‐functionalization with 2,2,6,6‐tetramethylpiperidin‐4‐yl‐diazoacetate. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Surface modification of polyethylene by Ag+ and Au+ ion implantation observed by phase imaging atomic force microscopy

High density polyethylene (HDPE) has been modified by Ag+ and Au+ ion implantation with the energy of 60 and 200keV, respectively. The doses of implanted silver and gold ions were as follows: 1×1015, 5×1015 and 1×1016 ions/cm2. The surface topography was observed using atomic force microscopy (AFM), while the surface composition changes were detected using phase imaging AFM. Phase analysis of AFM images shows that both physical and chemical changes occur on the surface of HDPE and that these changes depend on the nature of implanted ions and on the implantation dose. Silver ion implantation causes a higher degree of chemical changes, while the implantation of gold ions causes a higher degree of physical changes. Breakpoints were observed for the implantation doses of 0.6×1015 and 4.4×1015 ions/cm2 for silver and gold ions, respectively. Physical changes are confirmed by the analysis of mean square roughness and power spectral density slopes as functions of the implantation dose. The position and half-width of peaks in histograms of phase AFM images confirmed the changes in surface composition.

Surface Modification of Polyethylene with Multi-End-Functional Polyethylene Additives

We have prepared and characterized a series of multifluorocarbon end-functional polyethylene additives, which when blended with polyethylene matrices increase surface hydrophobicity and lipophobicity. Water contact angles of >112° were observed on spin-cast blended film surfaces containing less than 1% fluorocarbon in the bulk, compared to ~98° in the absence of any additive. Crystallinity in these films gives rise to surface roughness that is an order of magnitude greater than is typical for amorphous spin-cast films but is too little to give rise to superhydrophobicity. X-ray photoelectron spectroscopy (XPS) confirms the enrichment of the multifluorocarbon additives at the air surface by up to 80 times the bulk concentration. Ion beam analysis was used to quantify the surface excess of the additives as a function of composition, functionality, and molecular weight of either blend component. In some cases, an excess of the additives was also found at the substrate interface, indicating phase separation into self-stratified layers. The combination of neutron reflectometry and ion beam analysis allowed the surface excess to be quantified above and below the melting point of the blended films. In these films, where the melting temperatures of the additive and matrix components are relatively similar (within 15 °C), the surface excess is almost independent of whether the blended film is semicrystalline or molten, suggesting that the additive undergoes cocrystallization with the matrix when the blended films are allowed to cool below the melting point.

Modification and bio‐testing of polyethylene films

AbstractNew azidobenzenesulfonamides were synthesized and their photochemical properties were investigated. The surface modification of polyethylene (PE) films was carried out by using new azidobenzenesulfonamides was carried out.Antimicrobial activity of PE films with sulfonamide moiety was screened for vitro in the following bacterial: Staphylococcus aureus, Escherichia coli, Mycobacterium luteum. Preliminary screening of PE films with sulfonamide moiety revealed their inhibitory action against some kinds of bacteria and fungi.

Surface modification of polyethylene by medium pressure microplasma generator

Polyethylene surface modification studies were performed in a new microplasma source using O2 and N2 gases. The degree of modification of polyethylene surface was qualitatively investigated through water contact angle measurements using distilled water. The influence of the plasma discharge parameters, such as gas nature, gas flow, power and exposure time, over the polyethylene contact angle was investigated. The obtained results indicate a decrease of the contact angle from 100° (for untreated sample) to 22·9°, when N2 plasma was used for 40 s and discharge power >2 W. The surface morphology of the samples was examined by atomic force microscope and a smoothing effect after the plasma treatment was found. These results are very promising because of the experimental set‐up which requires medium vacuum, exhibit low process temperature (50–100°C) leaving the surface intact. Other advantages are the very short processing time (60 s) and applicability to large area substrates.

Surface modification of PE film by DBD plasma in air

In this paper, surface modification of polyethylene (PE) films is studied by dielectric barrier discharge plasma treatment in air. The treated samples were examined by water contact angle measurement, calculation of surface free energy, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The water contact angle changes from the original value of 93.2° to the minimum value of 53.3° and surface free energy increases from 27.3 to 51.89 J/m 2 after treatment time of 50 s. Both ATR and XPS show some oxidized species are introduced into the sample surface by the plasma treatment and that the change tendencies of the water contact angle and surface free energy with the treatment time are the same as that of the oxygen concentration on the treated sample surface. Cu films were deposited on the treated and untreated PE surfaces. The peel adhesive strength between the Cu film and the treated sample is 1.5 MPa, whereas the value is only 0.8 MPa between the Cu film and the untreated PE. SEM pictures show that the Cu film deposited on the plasma treated PE surface is smooth and the crystal grain is smaller, contrarily the Cu film on the untreated PE surface is rough and the crystal grain is larger.

Grafting of Acrylamide and Acrylic Acid onto Polyethylene Fiber for Improved Adhesion to Epoxy Resin

Surface modification of polyethylene (PE) fiber via 2-stage grafting to improve its adhesion to epoxy resin was studied. The PE fiber was first functionalized by thermal decomposition of potassium peroxydisulfate to create grafting sites. In the second stage, functionalized fiber was grafted with acrylamide (AAm) and acrylic acid (AAc) monomer by Ceric (IV) ion technique. The adhesion of grafted fibers to epoxy resin was studied by a single fiber pull out test. Pull out strength increases about 2 folds after functionalization and 3.5 and 4.8 folds after grafting with AAm and AAc, respectively. The improvement in pull out strength after functionalization and grafting are due to physical interaction and the formation of chemical bonding, respectively. Traces of transfering materials on the surface of pulled out fiber suggested that failure could be due to cohesive failure of either epoxy resin or grafted layer. Preliminary study of surface grafted fiber/epoxy composite showed significant improvement in flexural and impact strength over unreinforced resin and untreated fiber reinforced composite.

Diamond-like carbon films for polyethylene femoral parts: Raman and FT-IR spectroscopy before and after incubation in simulated body liquid

In artificial prosthetics for knee, hip, finger or shoulder joints, ultrahigh molecular weight polyethylene (UHMW-PE) is a significant material. Several attempts to reduce the wear rate of UHMW-PE, i.e. the application of suitable coatings, are in progress. A surface modification of polyethylene with wear-resistant hydrogenated diamond-like carbon is favourable, owing to the chemical similarity of polyethylene (-C-H(2)-)(n) and C:H or amorphous C:H (a-C:H) coatings with diamond-like properties. In the present study, the microstructure of a-C:H coatings on UHMW-PE substrates was investigated by Raman and Fourier transform infrared (FT-IR) spectroscopy. FT-IR spectroscopy shows very broad absorption lines, which point to the disorder and diversity of different symmetric, asymmetric aromatic, olefin sp(2)-hybridized or sp(3)-hybridized C-H groups in the amorphous diamond-like carbon coating. Following a long incubation of 12 months in a simulated body liquid, the structural investigations were repeated. Furthermore, fractured cross-sections and the wetting behaviour with polar liquids were examined. After incubation in simulated body liquid, Raman spectroscopy pointed to a reduction of the C-H bonds in the diamond-like carbon coatings. On the basis of these findings, one can conclude that hydrogenated diamond-like carbon is able to interact with salt solutions by substituting the hydrogen with appropriate ions.

Modification of polyethylene surface using plasma polymerization of silane

AbstractIn the present study plasma polymerization of tetraethylorthosilicate and hexamethyldisiloxane was carried out on polyethylene film with an aim of enhancing barrier properties. The glow discharge was obtained at 0.2 mbar using 13.56 MHz radio frequency source capable of giving power out put up to 100 W. The monomer vapors were passed in the system at the rate of 15 SCCM. The extent of deposition was determined from the weight gain study and the morphology was studied using SEM. Films were further characterized by surface energy measurement, ATR‐FTIR and ESCA analysis. Since PE is widely used for packaging and in this process a thin layer of glass‐like transparent SiOx was deposited, therefore it was thought necessary to study permeability to water vapors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007