Surface Of Polyethylene Films Research Articles

Study of the aging process of corona discharge plasma effects on low density polyethylene film surface

A study of the durability of corona discharge plasma effects on a polymer surface was investigated in this work. We used the corona discharge plasma technique to modify the wettability properties of low density polyethylene (LDPE) film and evaluated the influence of relative humidity and temperature on the aging process with three different storage conditions. The effects of the aging process on the plasma-treated surface of LDPE film were quantified by contact angle measurements, Fourier-transformed infrared spectroscopy, and X-ray photoelectron spectroscopy. The results obtained with these techniques have allowed us to determine how the aging process promotes changes in the plasma-treated surface by decreasing its wettability and taking place a remarkable hydrophobic recovery process.

Polyethylene film surface functionalized with chitosan via γ-ray irradiation in aqueous system: An approach to induce copper(II) ion adsorptivity on PE

Functionalization of the surface of polyethylene (PE) film with chitosan via γ-ray irradiation technique followed by copper ion immobilization on this surface is proposed. The solubilization of chitosan in water by forming an organic salt with hydroxybenzyl triazole is a key factor in accomplishing the surface functionalization of PE with chitosan by γ-ray irradiation. The chitosan induces the metal ion adsorptivity on PE film surface resulting in the successful copper ion immobilization. The work demonstrates an approach to convert a commodity polymer, such as PE, to a functional polymer with chitosan.

Application of hydrophilic starch‐based coatings on polyethylene surfaces

AbstractCoatings were applied to polyethylene (PE) film surfaces by spraying formulations prepared from a jet cooked dispersion of waxy cornstarch, a water‐born epoxy resin, a wax emulsion, and a fluorinated surfactant. The air‐dried coatings were comprised of discontinuous areas of polymer that adhered tightly to the PE surface. Although the starch component separated rapidly from the coating when the film was placed in water at room temperature, heating the coated film for 24 h at 80°C increased the adhesion of starch and produced a surface coating that remained uniformly wet when the film was placed in water. Most of the starch, however, could be still be removed by gently rubbing the wet surface. If melamine‐formaldehyde resin was added to the formulation as a crosslinking agent for starch, and the coated film was then heated for 24 h at 80°C, most of the starch remained bonded to the wet coating, even after the surface was gently rubbed. Identification of successful spray application techniques and formulations will allow the development of commercial production methods for starch‐coated PE films and similar products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Wetting behavior of modified vinylester resins on the surface of UHMWPE materials

A new testing method was used to observe on-line the dynamic wetting course of liquid resins on PE fabric. The measure procedures and data processing were introduced in detail. To aim at some applications of vinylester resins/polyethylene fiber composites, vinylester resins (VRs) were at first modified by three kinds of additives, including elastomer, liquid rubber and isocyanate-terminated prepolymer. Then the wetting behaviors of these modified resins on the surface polyethylene (PE) materials were observed. After they were modified by six kinds of elastomers, the infiltrate-steady-times of these resins on the surface of PE fabric all increased; only the contact angle of natural rubber-modified VR on the surface of PE film decreased. After VRs were toughened by three kinds of liquid rubbers, their wetting velocities all became slower and the contact angles on the surface of PE film all decreased. In addition, VRs were also modified by three kinds of isocyanate-terminated prepolymers, which were the products of different hydroxyl-terminated polymers reacted with methylene bisphenyl isocyanate and whose structures were characterized by means of GPC, DSC and FT-IR, respectively. The wetting state of these modified resins on the surface of PE materials suggested that the interfacial compatibility of modified VRs and PE fabric did not decrease at the same time when the other properties of vinylester resins changed.

Photoactive nanocoating for controlling microbial proliferation on polymeric surfaces

A novel antimicrobial polymeric surface coating involving photo-activated generation of the well-known microbiocidal agent hydrogen peroxide was investigated. Modified poly(ethylene imine) (PEI) polymers were prepared containing anthraquinone (AQ) moieties attached covalently to the amino functional groups of the PEI chains. These AQ-modified PEI polymers were applied from solution to the surface of corona-treated low-density polyethylene (LDPE) films. Photoreduction of the PEI-bound anthraquinone derivatives occurred on exposure to low energy UV light, resulting in efficient production of hydrogen peroxide from the coated film on exposure to air.

Determination of Amine and Aldehyde Surface Densities: Application to the Study of Aged Plasma Treated Polyethylene Films

The aim of this work was to test and to compare different methods reported in the literature to quantify amine and aldehyde functions on the surface of polyethylene (PE) films treated by ammonia plasma and to specify their stability against time. A low pressure ammonia plasma reactor was used to functionalize PE films with amine groups, which could be subsequently used for further immobilization of biomolecules. In order to determine the density of amine groups on the surface of treated films, various molecule probes and spectrophotometric analytical methods have been investigated. Two methods using (i) sulfosuccinimidyl 6-[3'-(2-pyridyldithio)-propionamido] hexanoate (sulfo-LC-SPDP) and (ii) 2-iminothiolane (ITL) associated with bicinchoninic acid (BCA) have been proved to be reliable and sensitive enough to estimate the surface concentration of primary amine functions. The amount of primary amino groups on the functionalized polyethylene films was found to be between 1.2 and 1.4 molecules/nm2. In a second step, the surface concentration of glutaraldehyde (GA), which is currently used as a spacer arm before immobilization of biomolecules, has been assessed: two methods were used to determine the surface density of available aldehyde functions, after the reaction of GA with the aminated polyethylene film. The concentration of GA was found to be in the same range as primary amine concentration. The influence of aging time on the density of available amino and aldehyde groups on the surfaces were evaluated under different storage conditions. The results showed that 50% of the initial density of primary amine functions remained available after storage during 6 days of the PE samples in PBS (pH 7.6) at 4 degrees C. In the case of aldehyde groups, the same percentage of the initial density (50%) remained active after storage in air at RT over a longer period, i.e., 15 days.

Efficacy of Two Acidic Sanitizers for Microbial Reduction on Metal Cans and Low‐Density Polyethylene Film Surfaces

This study investigated 2 sanitizer formulations and compared them with hydrogen peroxide (H(2)O(2)). Formulation number 1 contained citric acid and sodium dodecylbenzene sulfonate (SDBS). Formulation number 2 contained SDBS, citric, lactic, phosphoric acids, and benzoic acid. Low concentration levels of the sanitizers (1.0% for formulation 1 and 0.5% for formulation 2) were compared with 35% H(2)O(2) for their efficacies on Escherichia coli, Listeria innocua, and Saccharomyces cerevisiae inoculated onto low-density polyethylene (LDPE) films and metal cans at room temperature (23 +/- 1 degrees C) and 40 degrees C. The results showed that both formulations 1 and 2 required >120 s to sanitize both materials from microbial populations at room temperature, while <15 s was needed for the H(2)O(2). Except for formulation 1 on the E. coli inoculated LDPE film surface, the sanitizers completely eliminated the bacterial populations on both materials in 60 s at 40 degrees C. In general, the formulations were more effective for reduction of the microbial numbers on the can material when compared with the LDPE film. The E. coli showed greater tolerance for the sanitizers when exposed to the process conditions in this study. All sanitizers completely eliminated the test organisms in </=36 s at 40 degrees C when tested on a commercial Benco Aseptic packaging machine.

Intracellular Calcium Response and Adhesiveness of Chick Embryonic Retinal Neurons to Photoelectric Dye‐coupled Polyethylene Films as Prototypes of Retinal Prostheses

Photoelectric dyes, which absorb light and convert photon energy to electric potentials, were shown to stimulate retinal neurons in culture. One of these dyes coupled with polyethylene film surface, as a prototype of retinal prostheses, could induce intracellular calcium elevation in chick embryonic retinal tissues. In this study, we used retinal cells from chick embryos in which no photoreceptor outer segments yet developed, and assessed cell adhesiveness and response to the original and modified types of our retinal prostheses. Extruded-blown film of high density polyethylene was used as the original polyethylene film. Polyethylene film surface was modified either by coupling with type 1 collagen or by crystallization from the melt of the original polyethylene film. A photoelectric dye, 2-[2-[4-(dibutylamino)phenyl]ethenyl]-3-carboxymethylbenzothiazolium bromide, was coupled to these different types of polyethylene films through amide linkage. Retinal cells from chick embryos at the 12-day embryonic stage were cultured on the surface of dye-coupled films. The response of retinal cells to the dye-coupled films was observed by calcium imaging. Cell types, either neurons or glial cells, were detected by immunocytochemical staining and also observed by scanning electron microscopy (SEM). Intracellular calcium elevation was observed in cells, including both neurons and glial cells, on the surface of the original dye-coupled film, collagen-coated dye-coupled film, and dye-coupled recrystallized film, in contrast with no response of cells cultured on the dye-uncoupled plain film. Retinal neurons grew upon colonies of glial cells settling on the surface of all different types of the films. The number of retinal neurons on the collagen-coated dye-coupled film and dye-coupled recrystallized film was significantly larger than the number of neurons on the dye-uncoupled plain film (P = 0.0004, analysis of variance; P < 0.05, Tukey-Kramer test). With SEM, Muller cell-like large cells covered the original dye-coupled film and collagen-coated dye-coupled film, while neuron-like small cells settled directly on the dye-coupled recrystallized film and also formed large colonies on Muller-like cells. Retinal neurons and glial cells were cultured directly on the different types of dye-coupled polyethylene films. Photoelectric dye-coupled polyethylene films could be used as prototypes of retinal prostheses.

New composite membranes based on crosslinked poly(acrylic acid) and porous polyethylene films

A process for the preparation of new composite membranes via free-radical copolymerization of acrylic acid with a macromolecular crosslinker (allyloxyethylcellulose) on the surface of porous polyethylene films was proposed. To reveal the effect of the porous matrix on the properties of the composites, homogeneous hydrogel membranes based on crosslinked poly(acrylic acid) were studied. The swelling ratio and transport characteristics of the membranes during separation of ethanol-water mixture by pervaporation were determined depending on the ethanol concentration. It was found that all membranes at low ethanol concentrations (0–30 vol %) exhibited high swelling ratios, which drastically decreased in the range 30–40 vol % as a result of gel collapse. The composite membranes had a higher selectivity for water over a broad range of ethanol concentrations than homogeneous membranes, but a lower flux. It was found that the strength and elasticity of porous matrices was retained in the composite membranes, which became mechanically more isotropic owing to the presence of the crosslinked component.

Surface oxidation of polyethylene using an atmospheric pressure glow discharge with liquid electrolyte cathode

This study investigated the action of an atmospheric pressure air glow discharge (APGD) with aqueous electrolyte cathode onto the surface of polyethylene (PE) films. Distilled water and aqueous solutions of KCl and HCl were utilized as a cathode. The surface properties of PE were characterized by contact angle measurement followed by surface free energy calculation, Fourier transform infrared by attenuated total reflectance (FTIR-ATR), and XPS. After treating the PE surface, we observed OH groups, C O groups in ester, ketone, and carboxyl groups, and C O groups in unsaturated ketones and aldehydes. For a treatment time of 20 min and a discharge current of 40 mA, atomic concentrations of O and N were 12% and 2%, respectively, under distilled water application. Modification processes were able to improve the surface free energy of PE.

STUDIES ON PHOTOGRAFTING OF TRIMETHYLOL PROPANE TRIACRYLATE ONTO THE SURFACE OF LDPE FILMS

Photografting (λ300 nm) of trimethylol propane triacrylate (TMPTA) onto the surface of low-density polyethylene (LDPE) films was investigated at room temperature in a mixed solvent composed of acetone and water,using benzophenone (BP) as an initiator.It seems that the polyfunctional monomer could be grafted easily onto the surface,forming a cross-linked structure, and as confirmed by IR spectroscopy there were still some double bonds un-reacted.Influences on the photografting of TMPTA were examined and the experimental results indicated that longer irradiation time and higher monomer concentration were useful for the increase of grafted polymer conversion.At a certain concentration of BP,a maximum grafted polymer conversion was obtained,and the decrease of grafted conversion at higher BP concentrations was probably due to the absorption effect of initiator.The increase of grafted polymer conversion was observed with increasing the water contents.SEM images showed that a lot of small particles appeared on the surface of grafted films, and water contact angle measurements noted that the surface hydrophobicity was improved.

Properties of Conducting Composite Systems Containing Polypyrrole Layers on Porous Polyethylene Films

Conducting composite systems containing polypyrrole layers were prepared by in situ polymerization of pyrrole on the surface of porous polyethylene films. The polymerization was performed in the gas phase, in a monomer solution, and in supercritical CO2. The chemical structures, electrical conductivities, and mechanical, thermodeformational, and morphological characteristics of the composites obtained were compared.

Immobilization of soluble eggshell membrane protein on polyethylene film surface: Effect on the culture of NIH3T3 in vitro

AbstractPolyethylene (PE) film surface is modified by combining plasma treatment and soluble eggshell membrane protein (SEP) immobilization. Contact angle measurements, attenuated total reflectance infrared spectroscopy, and X‐ray photoelectron spectroscopy confirm that SEP adheres tightly to the PE film surface. Mouse 3T3 fibroblasts are used as model cells to evaluate the biocompatibility of PE film surfaces before and after modification. Plasma pretreatment can incorporate polar groups onto the surface, benefitting tight immobilization of SEP. The hydrophilicity of the PE film surface modified by combining plasma treatment and SEP immobilization is increased as evidenced by contact angle measurements, and the biocompatibility of the surface is greatly improved as shown by cell culture. The surface of the modified material can endure rinsing with 10% acetic acid (a good solvent of SEP), which would be an advantage for further application as a biomaterial. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1340–1345, 2006

Micro- and nanofiltration membranes on the base of porous polyethylene films

Polyethylene (PE) microfiltration films and composite nanofiltration membranes on their base have been elaborated. Microporous films are formed by melt extrusion process of linear PE without any heterogeneous admixtures. PE membranes of 10–15 microns in thickness are characterized by a large number of through flow channels with 0.01–0.50 μm in size, overall porosity 40–50%, mean size of pores is 0.045 microns. Specific properties of relief-like surface of PE membranes provide a very high adhesion of these films to any coatings. Composite membranes were prepared by deposition of polyacrylonitrile (PAN) layers onto the surface of PE films. Phase inversion method was used to form PAN layer. As a result the initial microporous hydrophobic film transforms into hydrophilic ultra-filtration and nanofiltration membrane. Polymer concentration of the casting solution has been varied. The preparation of composite membranes by phase inversion gives a possibility to form PAN layers onto PE porous films for effective cut-off of bovine serum albumin (BSA).

Enzymatic grafting modification of polyethylene film in nonaqueous solvents

Modification of the surface of polyethylene film was performed in aqueous organic solvents in the presence of horseradish peroxidase. The affecting factors such as solvents composition, initiator, reaction time and reaction temperature were investigated. It was found that the grafting efficiency is higher in dioxane than that in the other solvents used and the initiators substituted by electron donating group facilitates the grafting reaction. And the optimum reaction condition was determined to be reacting in the 40% dioxane solution at 40 °C for 2 hours. The treated film was characterized with scanning electron microscopy (SEM), UV-Vis spectra, FT-IR, and contact angle measurements. Polar groups such as –CO and –NH2 were found to appear on the treated surface and the surface of treated film become rougher than the untreated film. The contact angle with water decreased from 80 to 50 and the absorption of the treated film in ultraviolet area increased significantly, which indicates that the hydrophilicity of PE film had been increased.

Electrophysical Properties and Thermal-Deformation Stability of Composites Containing Polyaniline Layers Deposited on Porous Polyethylene Films

The conducting properties of composites prepared by deposition of polyaniline layers on the surface of porous polyethylene films from dispersions and by polymerization in situ were studied.

Cutaneous and Sensory Effects of Two Sanitary Pads with Distinct Surface Materials: A Randomized Prospective Trial

ABSTRACTBackground: Cutaneous and sensory effects of sanitary pads with a novel “fabric-like” polyethylene film surface (topsheet) were assessed. Methods: Cutaneous erythema and subjective sensory effects of a test pad with fabric-like film topsheet (group size: 53) and a commercial pad with a conventional nonwoven fabric topsheet (group size: 55) were compared in a randomized, examiner-blind, prospective trial lasting two menstrual cycles. Only the assigned pads were used menstrually. An assigned panty liner brand was worn intermenstrually at participant discretion. Primary outcome measures were 1) the frequency and severity of erythema of the vulva, perineum, buttocks, and upper thighs, as visually scored by using a standard scale postmenstrually (16–84 hours after flow cessation) and intermenstrually (days 12–16); 2) sensory irritation frequency as reported on daily diaries; and 3) product preference ratings. Results: The frequency and severity of erythema did not differ between groups except for cycle 2, when a statistically higher mean erythema score (in the barely perceptible range) occurred postmenstrually on the right thigh (commercial pad group) and intermenstrually on the buttocks (test pad group). The frequency of rubbing, itching, or burning sensations declined from about 2% after cycle 1 to less than 1% after cycle 2, with no consistent difference between groups. The test pad was preferred overall, especially for absorbency and soiling protection. Conclusions: The test pad was well tolerated and comparable in skin compatibility to a commercial pad with a history of acceptable use.

Photoelectric Dye‐coupled Polyethylene Film as a Prototype of Retinal Prostheses

Photoelectric dyes, which absorb light and convert photon energy to electric potentials, have been previously shown to stimulate retinal neurons in culture. In this study, a photoelectric dye was coupled to a polyethylene film surface and tested in vitro using retinal tissues from chick embryos at the 12-day embryonic stage, at which time outer segments of retinal photoreceptor cells have not yet developed. Carboxyl moieties were introduced to a polyethylene film surface by fuming nitric acid, and then a photoelectric dye, 2-[2-[4-(dibutylamino)phenyl]ethenyl]-3-carboxymethylbenzothiazolium bromide, was coupled to the film through amide linkage. Intracellular calcium elevation was observed with Fluo-4 in retinal tissues placed on the dye-coupled polyethylene film, in contrast to retinal tissues which had no contact with the film. The response was inhibited by calcicludine, a voltage-gated calcium channel blocker, and also by extracellular calcium depletion. The photoelectric dye, coupled to the polyethylene film surface, absorbed light under a dissecting microscope and stimulated neurons in retinal tissues, showing that the dye-coupled film could be used as a prototype of retinal prostheses.

Surface modification of polyethylene by plasma pretreatment and UV‐induced graft polymerization for improvement of antithrombogenicity

AbstractThe purpose of this study was to enhance blood compatibility of polyethylene (PE) films. Glycidyl methacrylate (GMA) was grafted onto the surface of PE by Ar plasma pretreatment and UV‐induced graft polymerization without photo‐initiator, then heparin was immobilized onto the poly (glycidyl methacrylate) segments. The surface compositions and microstructure of GMA graft polymerized PE films were studied by X‐ray photoelectron spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transfer Infrared (ATR‐FTIR) spectroscopy. It was confirmed that heparin was successfully immobilized onto the surface of PE films by XPS analysis. The antithrombogenicity of the samples was determined by the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and plasma recalcification time (PRT) tests and platelet adhesion experiment. Results indicated that the antithrombogenicity of modified PE was improved remarkably. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2014–2018, 2004

Surface Photografting Polymerization of Methyl Methacrylate in N,N‐dimethylformamide on Low Density Polyethylene Film

AbstractSummary: It was found that without additional photoinitiator, methyl methacrylate (MMA) dissolved in common solvent N,N‐dimethylformamide (DMF) could be photografted steadily on low‐density polyethylene (LDPE) film surface under UV irradiation. In short irradiation time (4 min) and at room temperature, high grafting efficiency (approaching 100%) and remarkable graft polymer amount (grafting percent is about 4.6%) was obtained. The possible reaction mechanism was based on the photosensitivity of DMF, which induced this photografting polymerization. This finding is useful to develop photoinitiator‐free grafting or photopolymerization system. Using SEM, special discrete globular structure was found on the MMA‐grafted LDPE film surface, and a possible model was proposed to interpret it.image