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Polyethylene Films (polyethylene + film)

Distribution by Scientific Domains

Polymers and Materials Science	45%
Chemistry	27%

Selected Abstracts

The Characteristics of Polyethylene Film for Stretch and Cling Film Applications

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2004
C.M. Small
Part I. A range of polyethylene films were prepared from metallocene linear low density polyethylene (m-LLDPE), linear low density polyethylene (LLDPE) and ultra low density polyethylene (ULDPE) resins, containing 0 and 8% polyisobutylene (PIB). FTIR, DSC and mechanical analysis techniques were used to investigate the effect of co-monomer type, density and melt flow index (MFI) on the mechanical performance, orientation and crystallinity of these films. The study established that co-monomer type and MFI were the greatest factors influencing mechanical performance and crystallinity. Crystallinity was found to be the most influential factor governing PIB migration in these films and this in turn was related to polymer type, density and MFI, High MFI, octene co-monomer films exhibited the highest orientation, tear resistance and tack strength and would therefore be suitable for stretch film applications. Ultra low-density polymers gave relatively low tack strength and poor overall mechanical performance. Part II. A range of ethyl vinyl acetate (EVA)/m-LLDPE/EVA co-extruded films was manufactured, with vinyl acetate (VA) co-monomer content of 6, 12 and 18% and PIB content from 0,20%. The films were aged at 45d,C for up to 28 days, to enable tack (cling) development. The results show that film tack strength improved significantly with ageing. Increased VA concentration in the surface layer also showed significant improvement in film tack strength. The film tensile strength, elongation and tear properties in both machine direction (MD) and transverse direction (TD) were not significantly affected by increase in PIB concentration. However, increased VA content showed slight improvement in MD mechanical performance of the films, TD properties were relatively unaffected. Films with 12 to 18% VA in the surface layers produced high surface tack film and the mechanical performance of these films were comparable to mono-layer polyethylenes. These films are suitable for stretch wrap applications and have reduced the overall concentrations of tack additives, though high VA films were more difficult to process. [source]

Chiroptical Properties of Terthiophene Chromophores Dispersed in Oriented and Unoriented Polyethylene Films

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 6 2004
Andrea Pucci
Abstract Summary: Two new chiral terthiophene chromophores II and III were prepared with 99% enantiomeric excess. Chiroptical properties of these dyes dispersed in ultra high molecular weight polyethylene (UHMWPE) films were determined and compared with the same properties in solution. In the solid state, the optical activity strongly depends on the interaction mechanisms within small crystalline aggregates of chromophores. The film morphology and chromophore dispersion were also investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The good correlation between chromophore aggregation and chiroptical activity of the binary films promotes circular dichroism (CD) as an effective technique for monitoring the phase dispersion behaviour of dichroic dyes into polymer matrices. By mechanical stretching of the film a linearly dichroic orientation of the chromophores is obtained which results in a high degree of linear dichroism. The influence of the uniaxial orientation of terthiophene molecules along the drawing direction of UHMWPE on the chiroptical properties of the films, and the possible application of the oriented devices as linear polarizers are discussed. Absorption and CD spectra of unoriented UHMWPEII film at different rotation angles ,. [source]

Morphology and High Modulus of Laminated Ultra-Drawn Polyethylene Films with Biaxial Orientation Prepared by Microwave Heating

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007
Mami Azuma
Abstract To improve the poor mechanical properties of uniaxially ultra-drawn films along the transverse direction, lamination of two ultrahigh molecular weight polyethylene/ethylene dimethylaminoethyl methacrylate copolymer blend films was carried out in the rectangular elongation direction by a microwave heating method. The characteristics of the successful laminated films were analyzed theoretically and experimentally. The original orientation of the crystallites for the blend films was maintained perfectly after lamination, and the preferential directions intersected each other. The Young's modulus increased symmetrically with respect to the 45 ° direction. This is the first report concerning a drastic improvement of the Young's modulus in the transverse direction for films ultra-drawn along one direction. [source]

Luminescent properties of PP and LDPE films and rods doped with the Eu(III)-La(III) complex

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2006
Roman Pogreb
Abstract The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene films and polypropylene-rods, both doped with these complexes, were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)-thenoyltrifluoroacetone-1,10-phenanthroline complex (1) and Eu(III)-La(III)-1,10-phenanthroline complex (2). Absorption, excitation, emission spectra and lifetime of luminescence were studied. The impact of the polymer matrix on the emission spectra was investigated. Emission spectra of the films were studied at room and helium temperatures. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) surface mapping showed that in the Eu(III)-La(III) complex europium forms islands (clusters) with a dimension of 1,µm, whereas lanthanum was dispersed more uniformly in the polymer matrix. Dependence of emission intensity on the excitation was determined. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Distribution of acrylic acid grafted chains introduced into polyethylene film by simultaneous radiation grafting with water and ethanol as solvents

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007
Zhengchi Hou
Abstract The graft copolymerization of acrylic acid onto low-density polyethylene films by simultaneous ,-ray irradiation was carried out. The effect of water and ethanol as grafting solvents on the distribution of grafted poly (acrylic acid) in the low-density polyethylene films was studied with optical microscopy observations of dyed and sliced samples and attenuated total reflection/Fourier infrared spectroscopy analysis. When no vigorous homopolymerization occurred, both polyethylene and poly(acrylic acid) existed in the grafted layer, and the thickness of the grafted layer and the poly(acrylic acid) concentration in the grafted layer increased with an increasing degree of grafting, regardless of the grafting conditions, the former increasing faster than the latter. In comparison with water as the solvent, in the absence of the inhibitor, homopolymerization could be suppressed to a certain degree in the ethanol solvent system, whereas in the presence of the inhibitor, obvious homopolymerization occurred at a lower monomer concentration, and both the degree of grafting and the thickness of the grafted layer were lower. Such differences could be explained by the chain transfer and the relatively low solubility of poly(acrylic acid) in ethanol. In addition, an experimental scheme using optical microscopy to observe the dyed and sliced polymers was optimized. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1570,1577, 2007 [source]

Active Packaging of Fresh Chicken Breast, with Allyl Isothiocyanate (AITC) in Combination with Modified Atmosphere Packaging (MAP) to Control the Growth of Pathogens

JOURNAL OF FOOD SCIENCE, Issue 2 2010
Joongmin Shin
ABSTRACT:,Listeria monocytogenes,and,Salmonella typhimurium,are major bacterial pathogens associated with poultry products. Ally isothiocyanate (AITC), a natural antimicrobial compound, is reportedly effective against these pathogenic organisms. A device was designed for the controlled release of AITC with modified atmosphere packaging (MAP), and then evaluated for its ability to control the growth of,L. monocytogenes,and,S. typhimurium,on raw chicken breast during refrigerated storage. In order to obtain controlled release during the test period, a glass vial was filled with AITC and triglyceride. It was then sealed using high-density polyethylene film. The release of AITC was controlled by the concentration (mole fraction) of AITC in the triglyceride and by the AITC vapor permeability through the film. The fresh chicken samples were inoculated with one or the other of the pathogens at 104 CFU/g, and the packages (with and without AITC-controlled release device) were flushed with ambient air or 30% CO2/70% N2 before sealing, and then stored at 4 °C for up to 21 d. The maximum reduction in MAP plus AITC (compared to MAP alone) was 0.77 log CFU/g for,L.,monocytogenes,and 1.3 log CFU/g for,S.,typhimurium. The color of the chicken breast meat was affected by the concentration of AITC. Overall, a release rate of 0.6 ,g/h of AITC was found to not affect the color, whereas at 1.2 ,g/h of AITC the surface of the chicken was discolored. [source]

1-Methylcyclopropene Counteracts Ethylene-Induced Microbial Growth on Fresh-Cut Watermelon

JOURNAL OF FOOD SCIENCE, Issue 6 2006
Bin Zhou
ABSTRACT:, The effects of exogenous ethylene, 1-methylcyclopropene (1-MCP), or both on microbial growth on watermelon fruit and watermelon slices were investigated. Freshly harvested seedless watermelons (Citrullus lanatus, cv. Sugar Heart) were treated with 0.5 or 1.0 ppm 1-MCP, 10 ppm ethylene, 1-MCP + ethylene, or left untreated as controls. Fruits were processed into wedge-shaped slices, packaged into rigid trays sealed with a polyethylene film with a 29.2 pmol s,1 m,2 Pa,1 oxygen transmission rate. The slices were evaluated after 0-, 6-, and 12-d storage at 5 °C. Ethylene treatment alone increased the populations of aerobic bacteria, lactic acid bacteria, and yeasts and molds on the packaged slices during storage compared to those on corresponding control slices and resulted in extensive juice leakage from the slices. The ethylene treatment also resulted in high aerobic bacterial counts throughout the flesh of whole melons compared to the controls. Treating watermelons with 0.5 or 1.0 ppm 1-MCP prior to ethylene exposure counteracted the deleterious effects of ethylene. Extending the time from harvest to 1-MCP treatment increased the population of aerobic bacteria, but had no detectable effect on the growth of lactic acid bacteria or yeasts and molds. The results indicate that low concentrations (0.5 or 1.0 ppm) of 1-MCP can be used on whole watermelon to avoid deleterious effects of exogenous ethylene to which the melons could be exposed during shipping or storage. [source]

Effect of benzyl isothiocyanate on tomato fruit infection development by Alternaria alternata

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2005
R Troncoso-Rojas
Abstract Benzyl isothiocyanate (BITC) is known to be a strong antifungal compound in vitro against different fungi. The effectiveness of benzyl isothiocyanate to control Alternaria alternata growth in vitro and in vivo was tested. BITC in vitro activity was evaluated in A alternata growing on potato dextrose agar and exposed to 0.025, 0.05, 0.1, 0.2 or 0.4 mg ml,1. In vivo activity was evaluated by exposing A alternata -inoculated tomato fruits for either 18 or 36 h to 0.28 or 0.56 mg ml,1 BITC packed on low-density polyethylene film (LDPF) bags. Additionally, the effect of BITC on post-harvest physiology and tomato quality throughout storage at 20 °C was evaluated daily by monitoring respiration rate and ethylene production, whereas total soluble solids, pH, titratable acidity and fresh weight loss were measured every 3 days. Results showed that the minimal inhibitory concentration of BITC in vitro was 0.1 mg ml,1. A combined use of 0.56 mg ml,1 BITC with LDPF for 18 h was the optimum treatment to control Alternaria rot in packed tomato fruit. No effect of BITC on respiration rate, ethylene production, total soluble solids, pH, weight loss and titratable acidity was observed. Results suggest that BITC can be used as a post-harvest treatment to control Alternaria rot in tomato fruit without detrimental effects on the tomato post-harvest quality. Copyright © 2005 Society of Chemical Industry [source]

Introducing a Flat Model of the Silica-Supported Bis(imino)pyridyl Iron(II) Polyolefin Catalyst

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 4 2006
Wei Han
Abstract Summary: A well-defined flat model of a supported homogeneous polyolefin catalyst is prepared on the basis of an immobilized bis(imino)pyridyl iron complex on a super flat silica surface. The amount of supported catalyst precursor is quantified using XPS. This model catalyst remains active over extended periods, i.e., an average activity of 0.25,×,103 kg PE,·,(molCat,·,h,·,bar),1 is obtained for 24 h of ethylene polymerization. The morphology of the nascent polyethylene film is investigated by SEM. A side-view SEM image of the PE produced from the supported bis(imino)pyridyl Fe catalyst. [source]

UV stabilising synergies between carbon black and hindered light stabilisers in linear low density polyethylene films

MACROMOLECULAR SYMPOSIA, Issue 1 2003
A. Richard Horrocks
Abstract The combined effects of selected carbon black pigments and hindered light stabilisers (HALS) on the UV stabilities of linear low density polyethylene film have been studied under UVA and UVB fluorescent radiation sources. While the presence of HALS do not change the chemistry of film photodegradation, whether they are low or high molecular variants, their presence significantly extends film lifetime relative to the sum of the effects of carbon black and HALS individually. These lifetime extensions may be defined in terms of a synergy factor defined with respect to film time to lose a specific percentage of a tensile property, namely t20, the time to lose 20% of initial elongation-at-break, or the carbonyl index associated with this condition. It is proposed that possible causes of this synergy are a result of the UV screening effect of the carbon black particles which provide lower concentrations of polymer radicals for the HALS component to interact with and/or an accompanying thermal stabilising effect by the latter as a consequence of the higher polymer local temperature during irradiation of pigmented films. [source]

Evaluation of plastic packages for guava refrigerated preservation

PACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2001
Angelo Pedro Jacomino
Abstract Guavas cv. ,Kumagai' were packed in several plastic materials and stored at 10°C and 85,90% relative humidity (RH) for 7, 14, 21 and 28 days (+3 days at 25°C). The plastic materials studied were: multilayer co-extruded polyolephine film with selective permeability (PSP), low-density polyethylene film (LDPE), LDPE film with mineral incorporation (LDPEm) and heat-shrinkable polyolephine film (SHR). Guavas not packed were taken as control samples. The physicochemical characteristics of the fruits, O2 and CO2 transmission rates of the packaging materials and gas composition at the package headspace were evaluated. The LDPE film, 69,µm in thickness, with the lowest permeability to both O2 and CO2, led to anaerobiosis and high CO2 concentration inside the packages and promoted physiological disturbances and changes in fruit flavour. The SHR film, 15,µm in thickness, was the most permeable to CO2 and had quite high O2 transmission, which modified the inner atmosphere of the packages slightly. The fruits packed in this film showed a poorer quality than the controls, possibly due to the heat produced during the shrinking of the film. The LDPEm film, 24,µm in thickness, was almost as permeable to CO2 but had reduced O2 transmission, promoting an atmosphere of equilibrium of 3% O2 and 4.5% CO2. Fruits packed in this film kept their skin colour and pulp firmness, suitable for consumption up to 14 days. The PSP film, 35,µm in thickness, had the greatest O2 transmission but just over half of the CO2 transmission of LDPEm, promoting an atmosphere of equilibrium of 0.5% O2 and 4.5% CO2 inside the packages. Fruits packed in such packages kept their physicochemical characteristics up to 21 days. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Distribution of acrylic acid grafted chains introduced into polyethylene film by simultaneous radiation grafting with water and ethanol as solvents

FLAVORS OF GREEN TEA CHANGE LITTLE DURING STORAGE

JOURNAL OF SENSORY STUDIES, Issue 4 2010
JEEHYUN LEE
ABSTRACT The objective of the current study was to determine how flavor changes in green teas that are stored over a period of 2 years (a commonly noted shelf life for green tea products in loose leaf form). Two Korean green teas were packaged in metalized multilayer polyethylene films and stored at an ambient temperature of,20C. Both green tea samples were evaluated by six highly trained descriptive panelists at 3, 6, 12, 18 and 24 months after their original packaging dates. The intensity of the major attributes changed minimally among the samples as they were evaluated over the 2-year period. The green tea samples that were stored for 6 months did not change, up to 12 months they changed little, and after 12 months the samples sometimes developed low levels of off-flavors such as medicinal, musty/new leather or grain flavors, or they became higher in characteristics such as tooth-etch. Overall, the findings of this study indicate that green tea will change minimally during the first year of storage and will change slightly more during the second of 2 years of storage. However, these changes appear to be minimal when the samples are packaged in metalized multilayer polyethylene films. PRACTICAL APPLICATIONS This research provides the first evidence that, even though the flavors of green tea may change, the change will be minimal during the first 1,2 years of storage in metalized multilayer polyethylene films. This research indicates that green tea leaves do have an extended storage time, at least in terms of sensory quality, and can be held for extended periods of time at room temperature. [source]

UV stabilising synergies between carbon black and hindered light stabilisers in linear low density polyethylene films

Antimicrobial efficiency and sorbic acid migration from active films into pastry dough

PACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2007
M. F. A. Silveira
Abstract Antimicrobial films of 25 and 70¯m thickness, incorporated with 7 and 3% sorbic acid, respectively, were layered with pastry dough without additive and evaluated for sorbic acid migration and antimicrobial efficiency. Pastry dough containing potassium sorbate layered with low-density polyethylene films (LDPE) was used as a control. The films/pastry sandwiches were stored in LDPE bags at 8 ± 1°C. After 40 days of storage, the dough layered with 25¯m/7% films showed a reduction of 2log cycles in the aerobic mesophilic count; however, there were no significant differences (p , 0.05) for the psychotropic and Staphylococcus spp. counts. For the dough layered with 70¯m/3% films there were reductions of 2 and 1.5log cycles in the mesophilic and psychotropic counts, respectively. In the control dough, the aerobic mesophilic, psychotropic and Staphylococcus spp. counts increased by 1.5, 1 and 2log cycles, respectively. Regardless of the film, the counts of filamentous fungi, yeasts and coagulase-positive staphylococcus were <1.0 ¥ 102CFU/g, whereas the coliform counts at 35 and 45°C, and Escherichia coli were <3.0 ¥ 100NMP/g. The diffusion coefficients of the sorbic acid from the films into the dough had values in the order of 10 -18m2/s. There were no differences (p , 0.05) between migration values among the films. The maximum additive release from the 25¯m/7% film into the dough after 20 days was 0.07%, and from the 70¯m/3% film after 9 days was 0.09%. Both values are below the maximum limit allowed by current legislation. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Development of electronic nose method for evaluation of residual solvents in low-density polyethylene films ,

PACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2007
Isinay E. Yüzay
Abstract Flexible packaging films containing high levels of residual volatile organic compounds (VOCs) can alter the flavour and odour of packaged foods. Currently, a range of gas chromatographic techniques and sensory evaluations are used for assessing the residual VOCs in packaging films. An objective method for assessing the residual solvents from low-density polyethylene (LDPE) was developed using an Alpha MOS Fox 3000 electronic nose (e-nose) equipped with 12 metal oxide semiconductor sensors. Three VOCs, ethyl acetate, ethyl alcohol and toluene, were chosen as models for solvents of interest in flexible food packaging analysis. LDPE film samples were spiked with single and binary mixtures of solvents and analysed using the e-nose and by GC,FID (HP 6890; Hewlett-Packard Co., Wilmington, DE). The responses obtained from the e-nose were processed using principal component analysis (PCA) and discriminate factorial analysis (DFA) in order to identify the residual solvents. Partial least squares analysis (PLS) was also used to quantify the amount of residual solvent and to correlate the e-nose results with gas chromatography, which is currently the standard method for determining residual VOCs in packaging films. There was good agreement between the e-nose responses and gas chromatography results for single solvents (r = 0.90,0.98). The technique also worked for binary solvent mixtures (r = 0.84,0.99). The electronic nose can be a viable alternative to traditional techniques while providing simplicity and objectivity, which would be extremely advantageous in routine quality control of residual solvents. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Effects of ozone exposure on the structural, mechanical and barrier properties of select plastic packaging films

PACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2002
Banu F. Ozen
Abstract The effects of ozone (O3) gas exposure at various concentrations and treatment times on structural, mechanical and barrier properties of polyethylene and polyamide films were investigated. Changes in the structure of the films were monitored using an FT-IR spectrometer. The results showed that O3 treatment affected polyethylene and polyamide films differently. While O3 treatment caused formation of oxygen-containing functional groups and degradation of polymeric chains in polyethylene films, O3 treatment of polyamide films significantly increased the ,C,N, stretch observed at 1125,cm,1 in the FT-IR spectra. The changes in the mechanical properties of polyethylene films depended on the O3 treatment conditions (temperature and O3 concentration were the most significant), but an increase in tensile strength of polyamide films was observed regardless of the treatment conditions. Permeability to O2 for both types of films decreased with increasing O3 treatment time. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Multilayered antimicrobial polyethylene films applied to the packaging of ground beef

PACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2001
Jung-Uk Ha
Abstract A natural antimicrobial agent, grapefruit seed extract (GFSE), was incorporated in a 0.5% or 1.0% concentration on the food-contact surface of multilayered polyethylene (PE) film by a co-extrusion or solution-coating process. The fabricated films were tested in their antimicrobial activity against several food spoilage microorganisms, and then applied to the packaging of ground beef. During the storage of the packaged beef at 3°C, changes in microbial counts, pH, TBA value and meat colour were monitored in order to see the effect of the packaging film on meat quality changes. Coating the PE film with GFSE with the aid of a polyamide binder resulted in a more effective level of antimicrobial activity on the agar plate medium than did its incorporation by a co-extrusion process. The film co-extruded with a 1.0% GFSE layer showed antimicrobial activity only against Micrococcus flavus ATCC 10240, while the film coated with 1.0% GFSE showed activity against several microorganisms, such as Escherichia coli IFO 3301, Staphylococcus aureus IFO 3060 and Bacillus subtilis IFO 12113. Both types of GFSE-incorporated multilayer PE films contributed to a reduction of the growth rates of aerobic and coliform bacteria on the ground beef, when compared to plain PE film. The film coated with a higher concentration (1.0%) of GFSE had a more pronounced effect than did the other films in inhibiting spoilage bacterial growth. They could also slow down chemical changes of the packaged beef. The GFSE-coated film was more effective in preserving beef quality, but the level of GFSE addition did not affect the quality changes of the beef. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Comparisons of Photo-Fries Rearrangements of 4-Dodecylphenyl Phenylacetate and Two Structurally Related Esters in Hexane and Polyethylene Cages.

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2006
How Important Are Anchoring Chains?
ABSTRACT Photo-Fries rearrangements of 4-dodecylphenyl phenylacetate have been investigated in polyethylene films with 0,71% crystallinity and in hexane over a range of temperatures. The results are compared to those reported previously from phenyl phenylacetate and 1-naphthyl tetradecanoate to assess the influence of a long alkyl chain on the in-cage motions of the intermediate singlet radical pairs. It is demonstrated that the reactivity and selectivity of intimate singlet radical pairs can be tuned by judicious placement of long-chain substituents and selection of a specific polyethylene type as the reaction matrix. [source]

Haze of polyethylene films,effects of material parameters and clarifying agents

POLYMER ENGINEERING & SCIENCE, Issue 5 2002
Erik Andreassen
Effects of material parameters on the haze of blown films were analyzed. Four linearlow-density polyethylenes (two metallocene grades and two Ziegler-Natta grades) were studied in combination with three additives (two sorbitol-based clarifying agents and a low-molecular-weight long-chain branched polyethylene). One of the sorbitol-based additives reduced the haze of both the metallocene materials in this study, but did not have any positive effect on the two Ziegler-Natta materials. The variation in haze among the four base materials was directly related to the root-mean-square surface roughness (,). When considering all 16 material/additive combinations, the link between haze and surface topography was not a simple ,-haze relationship, but the haze was correlated with the average distance between adjacent surface profile peaks, the average slope, and the power spectral density at high lateral frequencies. Both of the mechanisms referred to in the literature, extrusion-induced haze and crystallization-induced haze, were probably active for the films in this study. [source]

Study of oxidation after monoacrylate grafting on polyethylene

POLYMER INTERNATIONAL, Issue 8 2008
Ourida Iguerb
Abstract BACKGROUND: The surface properties of high-density polyethylene and linear low-density polyethylene were modified by grafting urethane monoacrylate monomer under UV irradiation. This graft polymerization was carried out on native substrates and on substrates pre-treated by wet oxidation, for different oxidation times. RESULTS: As the urethane monacrylate layer is crosslinked, its grafting efficiency was checked by dissolving the polyethylene substrates in hot toluene. Grafting was evidenced by Fourier transform infrared spectroscopy of the obtained residues, which showed that both the characteristic urethane acrylate (3350 cm,1) and polyethylene (2920, 730 and 720 cm,1) bands were observable for any polyethylene oxidation time. For an oxidation time longer than 10 hours, acrylate grafting was homogeneous and the grafted surface was smooth with a roughness of less than 10 nm. In addition, X-ray photoelectron spectroscopy analysis of the residues revealed that O/C had an average value of 0.19, which is lower than the value corresponding to pure acrylate (0.42), whereas N/C had an average value of 0.068, also lower than that of pure acrylate (0.09), thus confirming the grafting. CONCLUSION: A urethane monoacrylate layer was grafted on native and oxidized polyethylene films. For highly oxidized films, the grafted surfaces are smooth and homogeneous. Copyright © 2008 Society of Chemical Industry [source]