Antimicrobial polyethylene terephthalate (PET) treated with an aromatic N‐halamine precursor,m‐aramid

A commercial m‐aramid as N‐halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad‐dry‐curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m‐aramid solution, drying at 150°C for 3 min, and curing at 230°C for 3 min. The PET surface coated with m‐aramid was characterized using fourier transform infrared‐attenuated total reflection (FTIR‐ATR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm^?1 regions as characteristic of m‐aramid bands, which indicate the PET fabric coated with m‐aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m‐aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m‐aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N‐halamine moieties from the N‐halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram‐negative and Gram‐positive bacteria. The chlorinated PET coated with 10% m‐aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The mechanism of air/oxygen/helium atmospheric plasma action on PVA

The effect of the air/oxygen/helium atmospheric plasma treatment on desizing polyvinyl alcohol (PVA) on cotton fabric was discussed as compared with the conventional H2O2 desizing. The possible change mechanism of PVA during atmospheric plasma exposure was induced through a combination of weight loss of PVA after plasma, PVA dissolving rate in water at room temperature, X‐ray photoelectron spectroscopy, and Fourier Transform infrared spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Novel surface modification of high‐density polyethylene films by using enzymatic catalysis

The surface of high‐density polyethylene (HDPE) films was modified by an enzyme, soybean peroxidase (SBP). The enzymatic surface modification was performed using a peroxidase as catalyst and hydrogen peroxide as oxidizing agent. The chemical composition and morphology of HDPE surfaces were characterized by X‐ray photoelectron spectroscopy, infrared spectroscopy, and scanning electron microscopy. Results showed that after enzymatic treatment, the O/C atomic ratio of HDPE surfaces increased, and new functional groups such as –CO– appeared. Moreover, the surface of treated HDPE films became rougher than untreated surfaces. The hydrophilicity of treated and untreated HDPE films was analyzed by UV–vis spectroscopy and contact angle measurements. The decreased contact angle of the HDPE with water and increased adsorption ability of the surface to a water‐soluble dye clearly indicated that enzymatic treatment can significantly increase the hydrophilicity of the surfaces of HDPE films. The catalytic mechanism of SBP was also discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3673–3678, 2004     

Modification of poly(octadecene‐alt‐maleic anhydride) films by reaction with functional amines

Thin films of poly(octadecene‐alt‐maleic anhydride) on top of Si wafers and glass plates were modified by reactions with different functional amines to be used in future studies on the relevance of certain molecular surface properties for the covalent immobilization of proteins. For that aim, a strategy was developed and applied to convert the anhydride moieties of the copolymer by functional amines into side chains bearing hydrophilic groups of acidic (carboxylic acid, sulfonic acid), basic (amines), or neutral (poly(ethylene oxide) (PEO), glucose) character. The modification of the copolymer films was achieved through the two‐step formation of a cyclic imide, which was very stable in aqueous solution. Depending on the reactivity of the applied amine, the adjustment of the reaction time was suitable for the preparation of partially converted surfaces of the polymer film. Degrees of modification between 5 and 30% (according to X‐ray photoelectron spectroscopy data) were obtained. Annealing the modified polymer films induced efficient back‐formation of the anhydride groups. By reaction of the layered polyanhydrides with highly crosslinked diamines, amine‐functionalized polymer films were produced that were capable of binding secondary polyanhydride layers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1255–1266, 2003     

Micromechanical modeling of roll‐to‐roll processing of oriented polyethylene terephthalate films

In this article, the thermo‐mechanical time‐dependent behavior of oriented polyethylene terephthalate (PET) films, which are used as a substrate material for flexible Organic Light‐Emitting Diode (OLED)s, is analyzed. These films are subjected to conditions that are representative for the industrial manufacturing process. Effects of creep and thermal shrinkage are experimentally observed simultaneously. The aim of the article is to demonstrate the ability of the micromechanically‐based model, which was previously used to separately describe both creep and thermal shrinkage of the polyethylene terephthalate film, to simulate experimentally observed anisotropic behavior of the film under complex loading conditions. This anisotropic behavior results from the microstructure, the internal stress state, and differences in constitutive behavior of the phases. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43384.     

Structural investigations of poly(ethylene terephthalate)‐graft‐polystyrene copolymer films

Structural investigations of poly(ethylene terephthalate)‐graft‐polystyrene (PET‐g‐PS) films prepared by radiation‐induced grafting of styrene onto commercial poly(ethylene terephthalate) (PET) films were carried out by FTIR, X‐ray diffraction (XRD), and differential scanning calorimetry (DSC). The variation in the degree of crystallinity and the thermal characteristics of PET films was correlated with the amount of polystyrene grafted therein (i.e., the degree of grafting). The heat of melting was found to be a function of PET crystalline fraction in the grafted films. The grafting is found to take place by incorporation of amorphous polystyrene grafts in the entire noncrystalline (amorphous) region of the PET films and at the surface of the crystallites. This results in a decrease in the degree of crystallinity with the increase in the degree of grafting, attributed to the dilution of PET crystalline structure with the amorphous polystyrene, without almost any disruption in the inherent crystallinity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1949–1955, 2002; DOI 10.1002/app.10515     

Study of sulfonation mechanism of low‐density polyethylene films with fuming sulfuric acid

Sulfonation of low‐density polyethylene (LDPE) films with fuming sulfuric acid was studied by X‐ray photoelectron spectroscopy (XPS) and attenuated total reflectance (ATR) infrared spectroscopy. The ATR spectra showed the formation of C?C double bonds and multiple sulfur atom containing groups for the sulfonation of LDPE films. This led us to propose that the abstraction reaction of hydride ion by sulfur trioxide (SO₃) in fuming sulfuric acid might account for the formation of the C?C double bonds. It was considered that after the abstraction reaction, these double bonds react with SO₃, resulting in the production of alkene sulfonic acids and sultones, along with the formation of sulfate groups as a result of reaction of the double bonds with sulfuric acid. Experimental data by treatment of the sulfonated LDPE films with KOH and thiourea supported the proposed idea, estimating the approximate molar ratio of the products. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2435–2442, 2004     

Ferroelectric nanodot formation from spin‐coated poly(vinylidene fluoride‐co‐trifluoroethylene) films and their application to organic solar cells

We demonstrated a facile route to the preparation of self‐assembled poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐TrFE)] nanodots from spin‐coated thin films. We found that the initial film thickness would play an important role in the formation of such P(VDF‐TrFE) nanodots. Interestingly, the electric dipoles of such nanodots were self‐aligned toward the bottom electrode and their ferroelectric properties were determined by using piezoresponse force microscopy. In addition, the self‐polarized ferroelectric nanostructures were introduced to small molecular organic photovoltaic devices and allowed for enhancing the short circuit current density (J_sc) from 9.4 mA/cm² to 10.2 mA/cm² and the power conversion efficiency from 2.37% to 2.65%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41230.     

Surface modification of linear low‐density polyethylene film by amphiphilic graft copolymers based on poly(higher α‐olefin)‐graft‐poly(ethylene glycol)

In this article, a series of amphiphilic graft copolymers, namely poly(higher α‐olefin‐co‐para‐methylstyrene)‐graft‐poly(ethylene glycol), and poly(higher α‐olefin‐co‐acrylic acid)‐graft‐poly(ethylene glycol) was used as modifying agent to increase the wettability of the surface of linear low‐density polyethylene (LLDPE) film. The wettability of the surface of LLDPE film could be increased effectively by spin coating of the amphiphilic graft copolymers onto the surface of LLDPE film. The higher the content of poly(ethylene glycol) (PEG) segments, the lower the water contact angle was. The water contact angle of modified LLDPE films was reduced as low as 25°. However, the adhesion between the amphiphilic graft copolymer and LLDPE film was poor. To solve this problem, the modified LLDPE films coated by the amphiphilic graft copolymers were annealed at 110° for 12 h. During the period of annealing, heating made polymer chain move and rearrange quickly. When the film was cooled down, the alkyl group of higher α‐olefin units and LLDPE began to entangle and crystallize. Driven by crystallization, the PEG segments rearranged and enriched in the interface between the amphiphilic graft copolymer and air. By this surface modification method, the amphiphilic graft copolymer was fixed on the surface of LLDPE film. And the water contact angle was further reduced as low as 14.8°. The experimental results of this article demonstrate the potential pathway to provide an effective and durable anti‐fog LLDPE film. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface and adhesion properties of poly(ethylene glycol) on polyester(polyethylene terephthalate) fabric surface: Effect of air‐atmospheric plasma treatment

The surface and adhesion properties of different molecular weight poly(ethylene glycol) (PEG) (400, 1500, and 3000 g/mol) on untreated and air‐atmospheric plasma‐treated PET woven fabrics were studied, with the aim of developing durable hydrophilic PET fibrous structures. PEG application was carried out by padding of the PET fabric in aqueous solution of PEG followed by curing and drying. The surface properties of the PEG‐coated PET fabrics were then characterized using wicking test to measure the water contact angle (θ°) and capillary weight (W_c), and using atomic force microscopy (AFM) images in the tapping mode. Results showed that without a prior air‐atmospheric plasma treatment of the PET fabric, the water contact angle decreased and capillary weight increased with the three PEGs, implying an increase in the hydrophilicity of both inner and outer PET fabric fiber surface. Air‐plasma treatment of the PET fabrics before PEG coating increases further the hydrophilicity of the inner fabric fiber surface: the capillary weight was almost doubled in the case of the three PEGs. Best results were obtained with PEG 1500: water contact angle decreasing from 82° to 51°, and the capillary weight increasing from 11 mg to 134 mg. Moreover, wash fastness test at room temperature and at 80°C confirms improved adhesion of PEG‐1500 to the plasma‐treated PET woven fabric surface, while under the same conditions the plasma‐treated PET without PEG loses completely its hydrophilic character. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Improvement of the water selectivity of ULTEM poly(ether imide) pervaporation films by an allylamine‐plasma‐polymerized layer

The wettability and surface energy of extruded ULTEM poly(ether imide) films strongly increased (the water contact angle varied from 75 to 38° and the surface energy varied from 45.3 to 59.5 mJ m^?2, respectively) with the deposition of an allylamine‐plasma‐polymerized layer and were characterized with X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy according to the experimental parameters. Pervaporation tests for dehydrating the water/ethanol azeotropic mixture were performed at 40°C with nontreated and plasma‐treated ULTEM films for 15, 30, 60, and 120 min. No significant difference was noticed in the total flow (ca. 2.5 g/m² h) among the various films. However, for the 30‐min duration, a great increase in the water selectivity from 850 to 10,850 was measured, and it was related to the higher N/C ratio and the presence of amide groups on the surface. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2088–2096, 2005     

Surface modification of ultra‐high‐molecular‐weight polyethylene. II. Effect on the physicomechanical and tribological properties of ultra‐high‐molecular‐weight polyethylene/poly(ethylene terephthalate) composites

We performed surface modification of ultra‐high‐molecular‐weight polyethylene (UHMWPE) through chromic acid etching, with the aim of improving the performance of its composites with poly(ethylene terephthalate) (PET) fibers. In this article, we report on the morphology and physicomechanical and tribological properties of modified UHMWPE/PET composites. Composites containing chemically modified UHMWPE had higher impact properties than those based on unmodified UHMWPE because of improved interfacial bonding between the polymer matrix and the fibers and better dispersion of the fibers within the modified UHMWPE matrix. Chemical modification of UHMWPE before the introduction of PET fibers resulted in composites exhibiting improved wear resistance compared to the base material and compared to unmodified UHMWPE/PET composites. On the basis of the morphological studies of worn samples, microploughing and fatigue failure associated with microcracking were identified as the principle wear mechanisms. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Crystallographic texture, amorphization, and recrystallization in rolled and heat treated polyethylene terephthalate (PET)

This study is about crystallographic texture, deformation-induced decrystallization (disaggregation, amorphization), and subsequent recrystallization in rolled and heat treated semi-crystalline (triclinic) PET. Experiments are based on quantitative wide angle X-ray diffraction using an area detector. The change in crystallinity during rolling deformation and heating is analyzed in terms of X-ray data (peaks and background) that are integrated over the entire pole sphere. This method eliminates texture effects in the analysis of crystallinity. The rolling texture consists of a {100}〈001〉 component and an incomplete fiber (〈001〉‖rolling direction). The texture is explained by crystallographic shear mainly on {100}〈001〉 intralamellar shear systems. The X-ray analysis reveals that crystallinity drastically decreases during rolling. We suggest that amorphization (disaggregation, decrystallization) is a deformation mechanism which takes place as an alternative to crystallographic intralamellar shear depending on the orientation of the lamellae. Heat treatment (373, 473 K) leads to the recrystallization of amorphous material and to an enhancement of the original deformation texture. We explain the recrystallization texture in terms of an oriented nucleation mechanism where amorphous material aligns along existing crystalline lamellae.     

Lamination of polyethylene composite films by ultrasonic welding: Investigation of peel behavior and identification of optimum welding parameters

The lamination of different polyethylene (PE) composite films by ultrasonic welding to fabricate peelable seals that open at defined burst pressures is investigated. The sealing time, pressure, and amplitude were varied within the range of 100–400 ms, 50–250 kPa, and 12–24 µm, respectively. T‐peel tests and electron micrographs revealed four different peel regimes, depending on the parameter combination: (I) Interlaminar peeling at low‐peel strength with uniform peeling along a weakly bonded PE lamination layer; (II) transition tearing at intermediate peel strength showing areas of interlaminar peeling and translaminar tearing; (III) translaminar tearing at high‐peel strength showing tears through the entire film; and, (IV) undefined tearing at varying tear strength occurring when vibration effects during welding lead to insufficient contact of the films or high pressures lead to a displacement of PE. This study will allow the systematic adjustment of ultrasonic welding parameters for PE films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40291.     

Carbon nanotube surface-induced crystallization of polyethylene terephthalate (PET)

The crystallization of polyethylene terephthalate (PET) and its effect on the electrical behavior of nanocomposites of PET and carbon nanotubes (CNTs) was studied. A series of nanocomposites composed of polyethylene terephthalate/carbon nanotubes (PET/CNTs) containing 0, 1 and 2% wt/wt carbon nanotubes were prepared by melt extrusion. The morphology developed by the nanocomposites during non-isothermal crystallization at different cooling rates was evaluated using various experimental techniques. Thermal analysis showed an increase in the crystallization temperature of the nanocomposites, which was associated with the nucleation ability of the CNTs, and confined growth that resulted in a 3D-to-1D reduction in the crystallite geometry of the nanocomposites. X-ray diffraction indicated that the crystal structure of the nanocomposites was not affected by the presence of carbon nanotubes or the cooling rate. However, the crystallinity of PET and the nanocomposites increased as the cooling rate decreased. The electrical conductivity of the materials as a function of the cooling rate, at a constant CNT content, showed a marked (two orders of magnitude) increase in passing from the amorphous state to the crystalline state. The results of theoretical calculations indicated self-assembly between the surface of the nanotubes and the aromatic ring of PET; it was proposed that the stacking of aromatic rings on the surface of the nanotubes has an effect on the rearrangement of electric charge.     

Deposition of silicon oxide hard coatings by low‐temperature radio‐frequency plasmas

In this study, the deposition of silicon oxide (SiOx) hard coatings on polycarbonate (PC) substrates was attempted with low‐temperature radio‐frequency (RF) plasmas from tetramethyldisiloxane (TMDSO) with the addition of oxygen. The coating uniformity and deposition rate were investigated in terms of substrate size, glow uniformity, and RF power input. The hardness of the resulting SiOx plasma coatings was examined by the ASTM pencil hardness test method. The hardness of the resulting SiOx plasma coatings was mainly determined by the TMDSO–O₂ ratio in the plasma gas mixture. Ultraviolet–visible transmission spectra showed that these plasma coatings were transparent in the visible light region. Fourier transform infrared–attenuated total reflection analysis results indicated that the resulting SiOx plasma coatings were inorganic in nature. The interfacial adhesion, which is a common problem in the deposition of hard protective coatings on polymeric substrates, was also significantly improved by the deposition of an ultrathin plasma polymer interlayer from TMDSO before the deposition of the SiOx plasma coatings on the PC substrates. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Plasma‐induced graft polymerization of acrylic acid onto poly(ethylene terephthalate) films

The graft polymerization of acrylic acid was carried out onto poly(ethylene terephthalate) films that had been pretreated with argon plasma and subsequently exposed to oxygen to create peroxides. The influence of synthesis conditions, such as plasma treatment time, plasma power, monomer concentration, temperature, and the presence of Mohr's salt, on the degree of grafting was investigated. The observed initial increase in grafting with monomer concentration accelerated at about 20% monomer. The grafting reached a maximum at 40% monomer and subsequently decreased with further increases in monomer concentration. The reaction temperature had a pronounced effect on the degree of grafting. The initial rate of grafting increased with increasing temperature, but the degree of grafting showed a maximum at 50°C. The activation energy of the grafting obtained from an Arrhenius plot was 29.1 kJ/mol. The addition of Mohr's salt to the reaction medium not only led to a homopolymer‐free grafting reaction but also diminished the degree of grafting. The degree of grafting increased with increasing plasma power and plasma treatment time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2993–3001, 2001     

Investigation of plasma polymerized benzene and furan thin films for application in opto‐electronic devices

Conjugated polymers are among the most promising organic materials for opto‐electronic devices. In such applications, the main fabrication problem is to get uniform, defect‐free, and reproducible thin films of these materials. In this investigation, an RF plasma reactor was used to produce cross‐linked organic thin films from benzene and furan precursors. Uniform thin films of desired thickness were fabricated using this plasma polymerization technique. The composition of the plasma‐polymerized films was determined with X‐ray photoelectron spectroscopy. Fourier transform infrared spectra of the monomers and plasma‐polymerized thin films prepared were compared to analyze the chemical structure of the films. Ultraviolet–visible absorption spectroscopy shows a red shift of 45 nm in λ_max for the case of plasma‐polymerized benzene films and 52 nm in the case of plasma‐polymerized furan films when compared to their respective monomer spectra. Photo luminescence spectra of these films show a blue emission with a broad peak at 460 nm for the plasma‐polymerized benzene films and 445 nm for the plasma‐polymerized furan films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 523–528, 2003     

Contact angle determination on plasma‐treated poly(ethylene terephthalate) fabrics and foils

The surfaces of polyester (PET) fabrics and foils were modified by low‐pressure RF plasmas with air, CO₂, water vapor as well as Ar/O₂ and He/O₂ mixtures. To increase the wettability of the fabrics, the plasma processing parameters were optimized by means of a suction test with water. It was found that low pressure (10–16 Pa) and medium power (10–16 W) yielded a good penetration of plasma species in the textile structure for all oxygen‐containing gases and gaseous mixtures used. While the wettability of the PET fabric was increased in all cases, the Ar/O₂ plasma revealed the best hydrophilization effect with respect to water suction and aging. The hydrophilization of PET fabrics was closely related to the surface oxidation and was characterized by XPS analysis. Static and advancing contact angles were determined from the capillary rise with water. Both wetting and aging demonstrated a good comparability between plasma‐treated PET fabrics and foils, thus indicating a uniform treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1452–1458, 2006     

Surface characterization of low‐temperature cascade arc plasma–treated low‐density polyethylene using contact angle measurements

Low‐density polyethylene (LDPE) was treated with a low‐temperature cascade arc plasma torch (LTCAT) of argon with or without adding a reactive gas of oxygen or water vapor. The static sessile droplet method and the dynamic Wilhelmy balance method were employed to perform surface contact angle measurement in order to investigate and characterize the effects of LTCAT treatment on LDPE surfaces. These treatment effects included changes in surface wettability and surface stability and possible surface damage that would create low‐molecular‐weight oligomers on the treated surface. Experimental results indicated that the combination of static and dynamic surface contact angle measurements enabled a comprehensive investigation of these effects of plasma treatment on a polymer surface. Without the addition of a reactive gas, a 2‐s argon LTCAT treatment of LDPE resulted in a stable hydrophilic surface (with a water contact angle of 40°) and little surface damage. The addition of oxygen into argon LTCAT produced a less stable LDPE surface and showed more surface damage. Adding H₂O vapor into argon LTCAT produced an extremely hydrophilic surface (with a water contact angle < 20°) of LDPE but with pronounced surface damage. When compared with conventional radio frequency (13.56 MHz) plasmas, LTCAT treatment provides a much more rapid, effective, and efficient method of surface modification of LDPE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2528–2541, 2006