Coated Polypropylene Films Research Articles

Original antifouling strategy: Polypropylene films modified with chitosan‐coated silver nanoparticles

ABSTRACTA new coating strategy of polypropylene (PP) films with silver nanoparticles (AgNPs) is proposed to obtain surfaces with antifouling properties. As a first step, the photograft polymerization is used to produce polyacrylic acid‐grafted PP (PAA‐grafted PP) films. A green AgNP synthesis is used by thermal reduction of AgNO3 with amino groups of chitosan (CS), which controls ion diffusion and stabilizes nanoparticles. AgNP/CS complexes are adsorbed on PAA‐grafted PP by electrostatic interactions, yielding AgNP/CS‐coated PP films. These films show an excellent antimicrobial activity, even for AgNP contents as low as 0.08 wt %, reducing more than 4 log units in the viable Staphylococcus aureus concentration or inducing Escherichia coli death. This trend is consistent with an adequate amount of small AgNP adsorbed in an organized manner within a thin surface layer. Therefore, the antimicrobial activity of this film seems to be more than promising, used as an active surface for a wide range of applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48448.

Design of UV-Absorbing Polypropylene Films with Polymeric Benzotriaziole Based Nano- and Microparticle Coatings.

UV-absorbing nanoparticles (NPs) and microparticles (MPs) were prepared by emulsion and dispersion copolymerization of the vinylic monomer 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole (Norbloc (NB)) with the crosslinking monomer divinylbenzene. The effect of the initiator concentration on the size and size distribution of the polyNB (PNB) particles was elucidated. Thin coatings of the formed PNB NPs or MPs of 19 ± 2 and 200 ± 25 nm dry diameter, respectively, onto polypropylene (PP) films were then prepared and characterized. Increasing the concentration or thickness of the PNB NP or MP thin coatings on the PP films decreased their UV transmittance, up to complete UV blocking with just 2 μm of a 4% NP coating. Migration of the UV-absorbing agents from the coated PP films was not observed during three years of storage at room temperature, offering a unique solution to current problems of migration of UV-absorbing additives. The thin coatings obtained by the PNB NPs were superior to those of the PNB MPs, in that no UV transmittance or loss of optical properties of the PP films were observed for the NP coatings, while the coatings produced by the PNB MPs resulted in damaged optical properties, particularly increasing the haze, and achieved incomplete UV blocking.

Influence of non-thermal TiCl4/Ar + O2 plasma-assisted TiOx based coatings on the surface of polypropylene (PP) films for the tailoring of surface properties and cytocompatibility

The superior bulk properties (corrosion resistance, high strength to weight ratio, relatively low cost and easy processing) of hydrocarbon based polymers such as polypropylene (PP) have contributed significantly to the development of new biomedical applications such as artificial organs and cell scaffolds. However, low cell affinity is one of the main draw backs for PP due to its poor surface properties. In tissue engineering, physico-chemical surface properties such as hydrophilicity, polar functional groups, surface charge and morphology play a crucial role to enrich the cell proliferation and adhesion. In this present investigation TiOx based biocompatible coatings were developed on the surface of PP films via DC excited glow discharge plasma, using TiCl4/Ar+O2 gas mixture as a precursor. Various TiOx-based coatings are deposited on the surface of PP films as a function of discharge power. The changes in hydrophilicity of the TiOx/PP film surfaces were studied using contact angle analysis and surface energy calculations by Fowke's approximation. X-ray photo-electron spectroscopy (XPS) was used to investigate the surface chemical composition of TiOx/PP films. The surface morphology of the obtained TiOx/PP films was investigated by scanning electron and transmission electron microscopy (SEM &TEM). Moreover, the surface topography of the material was analyzed by atomic force microscopy (AFM). The cytocompatibility of the TiOx/PP films was investigated via in vitro analysis (cell viability, adhesion and cytotoxicity) using NIH3T3 (mouse embryonic fibroblast) cells. Furthermore the antibacterial activities of TiOx/PP films were also evaluated against two distinct bacterial models namely Gram positive Staphylococcus aureus (S.aureus) and Gram negative Escherichia coli DH5α. (E.coli) bacteria. XPS results clearly indicate the successful incorporation of TiOx and oxygen containing polar functional groups on the surface of plasma treated PP films. Moreover the surface of modified PP films exhibited nano structured morphology, as confirmed by SEM, TEM and AFM. The physico-chemical changes have improved the hydrophilicity of the PP films. The in-vitro analysis clearly confirms that the TiOx coated PP films performs as good as the standard tissue culture plates and also are unlikely to impact the bacterial cell viability.

Polyglycerol coated polypropylene surfaces for protein and bacteria resistance

Polyglycerol coated polypropylene films were prepared in two steps by plasma bromination and grafting of polyglycerol. Films were characterized and their bioinertness against proteins and bacteria was investigated.

Antibacterial effectiveness of chitosan–propolis coated polypropylene films against foodborne pathogens

Antibacterial properties of chitosan are well documented in the literature. However its antibacterial effectiveness in the film form is controversial due to the methodological differences in test methods used. In this study, antibacterial effectiveness of chitosan-coated polypropylene films alone and incorporating ethanolic extract of propolis (EEP) were evaluated against six foodborne pathogens (Bacillus cereus, Cronobacter sakazakii, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus) using the ISO 22196 method designed for the antibacterial treated plastic products. The results demonstrated that chitosan coated film exhibited the broad-spectrum antibacterial activity. Incorporation of EPP to coating at 10% (propolis resin/chitosan) enhanced antibacterial activity against all pathogens tested. Results of this study revealed that chitosan has antibacterial activity in the film form and that propolis is a promising antimicrobial for the food packaging applications.

Barrier properties of corn zein nanocomposite coated polypropylene films for food packaging applications

The feasibility of corn zein nanocomposite (CZNC) coatings as an alternative to synthetic polymer barrier layer on polypropylene (PP) films was examined. The effect of layered silicate content in the CZNC layers on the barrier and surface hydrophobicity of the CZNC-PP films were investigated. Incorporation of organomodified montmorillonite (OMMT) by solution intercalation into zein matrix significantly improved oxygen and water vapor barrier of coated PP films. The barrier properties were also investigated theoretically by using various phenomenological permeability models. Tortuous permeation path formed by the fine delamination of nanoclays was found to be responsible for the barrier improvements in zein layers. In conclusion, durable CZNC-PP laminates were developed. CZNC coating of PP films has reduced the oxygen permeability nearly four times, while water vapor permeability reduced by 30% with 5wt.% OMMT content in 5.9μm corn zein coating.

Plasma Surface Functionalization of Biaxially Oriented Polypropylene Films with Trimethyl Borate

The radiofrequency plasma (13.56 MHz) was employed to polymerize trimethyl borate (TMB) monomer/N2 gas mixture on the surface of biaxially oriented polypropylene (BOPP) films. Plasma polymer coated polypropylene films were examined by flame retardancy test (limiting oxygen index, LOI). The highest LOI value calculated for the untreated BOPP sample was 18.4 (v/v O2%) and 24.2 (v/v O2%) for the 55 W 30 minutes treated sample. The plasma polymers were characterized by FTIR spectroscopy and AFM. According to the FTIR results, the -OH, B-CH3, B-O, and BH2 functional groups were detected. It was found that the highest surface roughness belonged to 40 W 30 min treated BOPP sample which was calculated as 9.78 nm (10 μm × 10 μm). Moreover, the wettability of the modified BOPP film surfaces was characterized via contact angle measurements. The water contact angle values have decreased from 109.6? to the lowest value of 68.2? after the plasma treatment. The results showed that TMB/N2 plasma modification could be used as an alternative method for the enhancement of flame retardancy and hydrophilicity of BOPP film.

Behavior of Ink Jet Printed Drops on a Corona-Treated Polymeric Film Substrate

The effects of corona discharge treatment (CDT) on ink drop impact and spreading on a coated polypropylene film substrate were investigated. Substrate surface energies were determined from static contact angles with water and ethylene glycol. The polar component increased with increasing CDT. Drops 39 μm in diameter of an acrylate-based UV-curable ink were printed on to the substrate, and the spreading process studied by high-speed photography. No changes occurred during the initial stages, but the wetting phase was shorter for higher doses of CDT. Drops spread further on substrates with low doses of CDT than with higher doses. White light interferometry was used to determine the final heights of drops after UV-curing. The height was significantly affected by CDT, with minimum height at low doses. The relationship was investigated between the static contact angle for large sessile drops and the equilibrium contact angle for printed drops after spreading. Contact angle measurements with millimeter-sized sessile drops of ink provide a reliable method to determine the effects of corona treatment on wetting by ink jet printed drops.

Effect of corn‐zein coating on the mechanical properties of polypropylene packaging films

AbstractIn this study, a novel film structure of corn zein coated on polypropylene (PP) synthetic films for food packaging applications was developed, and the mechanical properties of the resulting coated film, as affected by the coating formulation, were investigated. Composite structures of PP films coated with corn zein were obtained through a simple solvent casting method. Different amounts of corn zein (5 and 15%) were dissolved in 70 and 95% aqueous ethanol solution at 50°C. Solutions of corn zein plasticized with poly(ethylene glycol) and glycerol (GLY) at various levels (20 and 50%) were applied on corona‐discharge‐treated PP. A statistical analysis based on full factorial design was performed to examine the influence of the coating formulation on the final properties of the corn‐zein‐coated PP films. A significant (p < 0.05) improvement in the coated film's mechanical properties was observed compared to those of the uncoated PP. The effect of the plasticization of the coating solutions was also quite significant. In general, GLY provided better improvements in the mechanical properties of the corn‐zein‐coated PP films. The statistical analysis of the results showed that the corn‐zein and plasticizer concentrations and plasticizer type used in the coating formulations were more effective parameters and had significant effects on the mechanical behavior of the coated PP films. In conclusion, corn‐zein coatings could have potential as alternatives to conventional synthetic polymers used in composite multilayer structures for food packaging applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Water vapor and oxygen-barrier performance of corn–zein coated polypropylene films

A novel corn–zein coating structure on polypropylene (PP) films was developed to examine its feasibility as an alternative water vapor and oxygen-barrier for flexible packaging industry. The barrier properties of the resulting films were evaluated as affected by coating formulation (solvent, corn–zein, plasticizer concentration and plasticizer type). Corn–zein with different amounts (5% and 15%) was dissolved in 70% and 95% aqueous ethanol solution at 50 °C, respectively. Solutions of corn–zein plasticized by polyethylene glycol (PEG) and glycerol (GLY) with various levels (20% and 50%) were applied on corona-discharged-treated PP by using solvent-casting method. The significant improvements in water vapor and oxygen-barrier properties of uncoated PP films were obtained with corn–zein coating. Water vapor permeability (WVP) of the coated films decreased significantly with increasing corn–zein concentration. The application of plasticized corn–zein coating on PP films showed nearly more than three order of reduction in oxygen permeability (OP). The high water vapor and oxygen-barriers were obtained for films coated with coating formulation consisting of higher amounts of corn–zein plasticized by GLY. The statistical analysis defined the key parameters of coating formulation that had major effect on the final properties of coated PP films as corn–zein, plasticizer concentration, and plasticizer type.

Effects of different sealing conditions on the seal strength of polypropylene films coated with a bio‐based thin layer

AbstractThis paper presents the results of an investigation through the design of experiment technique regarding the influence of temperature, dwell time and bar pressure on the heat seal strength of oriented polypropylene films coated with a gelatin‐based thin layer. This chemometric approach allowed achieving a thorough understanding of the effect of each independent factor on the two different responses (maximum force and strain energy) considered in this work as a measure of the strength necessary to break the bond across the sealed interface. Surprisingly, the factor affecting both responses the most was the bar pressure rather than the sealing temperature. Moreover, whereas the bar pressure negatively affected the seal strength of coated polypropylene films, the sealing temperature had a positive effect. Dwell time did not have any significant influence as a main factor, while influencing negatively the seal strength as an interaction term (i.e. time × pressure), together with the further interaction temperature × pressure. The mathematical models obtained for the two responses provided different results in terms of fitting capability (R2) and prediction ability (Q2). In particular, for the maximum force response, R2 and Q2 were equal to 0.571 and 0.405, respectively, whereas the model supporting the strain energy response gave R2 = 0.932 and Q2 = 0.937, highlighting that for quantifying the seal strength, the energy necessary to break a seal is a better measure than the maximum force. The highest seal strength values obtained during this work were of 0.6615 N and 19.6 N·mm for maximum force and strain energy, respectively. Copyright © 2009 John Wiley & Sons, Ltd.

Water vapour barrier performance of corn-zein coated polypropylene (PP) packaging films

The novel film structure of corn-zein coated on polypropylene (PP) synthetic film for packaging industry was developed to examine the feasibility of resulting coated films as an alternative water barrier performance for food packaging. The effects of coating formulation (solvent, corn-zein, plasticizer concentration and plasticizer type) on final properties of films were observed. Corn-zein is the most important protein of corn and has good film forming property. Composites structures of PP films coated with corn-zein were obtained through a simple solvent casting method. Polyethylene glycol (PEG) and glycerol (GLY) were used as plasticizer to increase film flexibility. Statistical analysis based on full factorial design was performed to observe coating formulation effects. The high water vapour barriers were obtained for films coated with coating formulation consisting of higher amounts of corn-zein plasticized by GLY. The lower glass transition temperatures (Tg) of films were obtained by plasticization of films and Tg decreased by increasing plasticizer content. The statistical analysis defined the key parameters of coating formulation that had major effects on the final properties of coated PP films as corn-zein, plasticizer concentration and plasticizer type. In conclusion, corn-zein coatings could have potential as an alternative to conventional synthetic polymers used in composite multilayer structures for food packaging applications.

Characterisation of flame retardant plasma polymer deposited BOPP film

Flame retardancy of polypropylene films was studied by plasma polymerisation technique. The surface of BOPP film was modified by boron containing plasma polymers at different plasma conditions. Plasma polymer coated polypropylene films were examined by flame retardancy test (limiting oxygen index, LOI) and TGA. Boron containing plasma polymer deposition on the film surface showed an improvement of flame retardancy. Furthermore, TGA thermograms pointed out that the first degradation temperature of treated polypropylene film was increased from 331 to 396°C, and the second degradation temperature was shifted from 401 to 455°C. Also, the plasma polymers were characterised by FTIR spectroscopy and XPS. According to XPS results, the BOPP surfaces treated with TMB showed significant difference in the composition with respect to the untreated sample. The FTIR spectra of plasma polymers obtained indicated that when the treatment time was increased to 60 min with a constant discharge power at 80 W, the absorption intensities of all the functional groups increased. As a result, boron containing plasma polymer treatment was found to be an effective method in enhancing the flame retardancy of BOPP film.

Wettability of polypropylene films coated with SiO x plasma deposited layers

Surface wettability of polypropylene (PP) films has been significantly improved by the deposition of thin SiO x layers, elaborated from a mixture of hexamethyldisiloxane (HMDSO) and oxygen in a microwave DECR (distributed electron cyclotron resonance) plasma reactor (2.45 GHz, 400 W). Contact angle measurements, Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to study, respectively, the change in surface free energy, surface topography and chemical composition due to the deposition of thin SiO x layers. Contact angle measurements revealed that the water contact angle value is reduced from about 99° for untreated PP surface to nearly 30° for coated PP film. The polar component of the surface energy is considerably increased from 0.5 to 35 mJ/m 2. For films deposited in the presence of VUV photons, AFM images showed the growth of irregular structure due to substrate etching effect and the deconvolution results of the Si 2p XPS peaks indicated that the proportion of the partly oxidized silicon environment was the major component. However, for films deposited without the presence of VUV radiation, typical SiO 2 agglomerates can clearly be seen on PP surface at a thickness of about 29 nm and the proportion of the silicon dioxide was the major component.

暮らしの中のガス透過膜とガスバリア膜 ガスバリア性フィルム包材・ＰＥＴボトルの技術動向

Gas-barrier property is a most important factor for food packaging. Now polyvinylidene chloride (PVDC) resins are still in wide use as gas-barrier films. However, PVDC resins as packaging materials have been declining in face of various environmental problems they pose. Under these circumstances, ethylene vinyl alcohol co-polymer (EVOH) films, polyvinyl alcohol (PVA) -coated polypropylene films, MXD6 nylon resins, and silica-or alumina-coated PET films are becoming the mainstream for gas-barrier purposes.Recently, various types of oxygen scavengers have been developed and applied as active packaging materials. PET bottles having oxygen barrier or scavenging properties are now used for plastic beer bottles in Europe and United States. EVOH and MXD6 nylon are used as the oxygen barrier materials. As the oxygen scavenging materials, the blend of MXD6 nylon and cobalt salt are used for PET bottles.In Japan, oxygen scavenging PET bottles are used for plastic tea bottles.

On‐going solutions to environmental issues in plastic packaging

AbstractRecently, the consumption of polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) resins as packaging materials has been declining in the face of various environmental problems they pose. To replace PVC containers, the use of PET bottles and A‐PET containers is on the increase, but PVDC resins are still in wide use as gas‐barrier materials. For gas‐barrier purposes, however, ethylene vinyl alcohol co‐polymer (EVOH) films, polyvinyl alcohol (PVA)‐coated polypropylene films, and MX nylon or silica‐ or alumina‐coated PET films are becoming mainstream. The weight reduction of plastic bottles is considered to play an important role in tackling the waste disposal problem. Recently, a new type of stretch‐blow moulding system has been developed, which is effective in reducing the weight of PET bottles. This system is called COSMOS (complete stretch‐blow moulding system) or the two‐blow system. COSMOS PET bottles are now used to hold carbonated drinks containing fruit juice or lactic acid. Copyright © 2001 John Wiley & Sons, Ltd.

Recycling of vinylidene chloride copolymer coated polypropylene film: a study of the thermal degradation of VDC copolymer

Thermogravimetric analysis has been used to study the dehydrochlorination of VDC copolymer. Dynamic and isothermal methods have been compared and the problem of active mass considered. Results indicate that whilst useful information can be rapidly obtained from a single dynamic analysis, consistency and accuracy are often compromised compared to isothermal studies.

A System for Continuous Monitoring of Whole Shoot CO2Exchange as an Adjunct to Growth Analysis Experiments in Controlled Environments

A multichannel system is described in which continuous CO2 exchange measurements of whole shoots can be made on plants grown in controlled environments such as growth cabinets, glasshouses, or plastic houses. The shoot enclosure is made from a coated polypropylene film which not only combines excellent light transmittance with poor permeability to CO2 but can also be tailored easily to individual shoot systems of various sizes ensuring a rapid response time for CO2 exchange measurements. Air speeds within the enclosure are regulated precisely; temperature and relative humidity are also controlled to within narrow limits, during daylight hours and at night. Thus, the aerial environment of enclosed shoots parallels closely that of non-enclosed plants. The system compliments a root respiration chamber designed earlier; used in conjunction with growth analysis data, the two systems facilitate quantitative determinations of the carbon economy of entire plants throughout all stages of growth.