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Packaging Films (packaging + film)
Selected AbstractsEvaluation of the Genotoxicity of Chitosan Nanoparticles for Use in Food Packaging FilmsJOURNAL OF FOOD SCIENCE, Issue 6 2010Renata De Lima Abstract:, The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the,Allium cepa,chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging. [source] Illegal Route Estimation of the Seized Illicit Drug, Methamphetamine, by the Comparison of Striation Marks on Plastic Packaging FilmsJOURNAL OF FORENSIC SCIENCES, Issue 6 2009Ritsuko Sugita Ph.D. Abstract:, In Japan, the most common illicit drug is methamphetamine. It is possible to trace the origin of this drug by analyzing its organic and inorganic impurities and/or byproducts using several methods, such as GC, GC/MS, and inductively coupled plasma-mass spectrometry (ICP-MS). As reported here, one other method includes comparison of the striation lines of polymer sheet layers from packaging using a polarized light method. Other alternative methods include analyzing the heat sealer pattern, layer thickness surface characteristics, and/or components of polymer sheet layers using infrared spectroscopy. Several of these alternative methods were used to analyze the origins of 29 packages confiscated from three regions over a 1000 km distance in Japan. Results indicated that packages seized from different regions had some polymer sheet layers which contained striation lines and heat sealer patterns that were similar. [source] Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical propertiesADVANCES IN POLYMER TECHNOLOGY, Issue 4 2009R. S. Jagadish Abstract In this investigation, modification of polypropylene (PP) with an objective to obtain packaging film with improved gas barrier properties has been studied. The chemical reaction of PP resin with hexamethylene diisocyanate and toluene diisocyanate was monitored by Fourier transform infrared spectroscopy, wherein the appearance of new peaks at 3333 cm,1 for NH stretching, 1620,1641 cm,1 for (CO)NH stretching and 1552,1578 cm,1 corresponding to NH bending in an amide moiety was observed for both the modified PP films. Films of excellent clarity and uniform thickness were obtained by the extrusion of cross-linked polypropylene. The barrier, mechanical, optical, and thermal properties of the modified PP films were studied. The results clearly indicated significant changes in gas barrier and mechanical properties. Food compatibility of the films was evaluated by overall migration in to different food simulants. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 28:233,245, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20168 [source] Ecophysiological attributes of a Lactobacillus sp. and a Pseudomonas sp. on sterile beef fillets in relation to storage temperature and film permeabilityJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2001E. Tsigarida Aims:,To determine the combined effect of packaging film and temperature on the rate and type of end-products caused by the growth of two main contrasting prevailing organisms in air and 100% CO2, Pseudomonas sp. and Lactobacillus sp., respectively. Methods and Results:,Pseudomonas sp. and Lactobacillus sp. were inoculated individually on sterile meat fillets. The samples were packed in air or 100% CO2, using a high and a low permeable film, and stored at 0 and 10°C. Pseudomonas sp. grew aerobically and in 100% CO2 using high permeable film at both storage temperatures, while film permeability significantly affected the growth of Lactobacillus sp. only at 10°C. Enzymatic kits and HPLC and GC analysis were used to determine the chemical changes of the samples throughout storage. Pseudomonas sp. presented a greater rate of consumption of glucose and lactate than Lactobacillus sp. in samples stored aerobically or with high permeable film. Propanol-1 and two unidentified organic acids were present only in samples inoculated with Pseudomonas sp., while acetaldehyde, ethanol, diacetyl and acetoin were detected in samples inoculated with Lactobacillus sp. Conclusions:,Since different microbial species and introduction of new packaging methods affect spoilage reactions of meat either qualitatively or quantitatively, a combination of several chemical indicators should be thoroughly investigated. Significance and Impact of the Study:,The present study provides information on how and when such potential indicators can be exploited for the benefit of the industry and consumer. [source] Blending of low-density polyethylene with vanillin for improved barrier and aroma-releasing properties in food packagingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009R. S. Jagadish Abstract Modification of low-density polyethylene (LDPE) with vanillin to obtain flavored packaging film with improved gas barrier and flavor-releasing properties has been studied. The modification of LDPE with vanillin was monitored by Fourier transform infrared spectroscopy, wherein the appearance of new peaks at 1704.7, 1673.6, and 1597.2 cm,1 indicates the incorporation of vanillin into LDPE matrix. Films of uniform thickness were obtained by the extrusion of modified LDPE. Modified LDPE was found to have significantly higher gas barrier properties and grease resistance. Sensory quality of food products viz, doodhpeda (milk-based solid soft sweet), biscuit, and skimmed milk powder packed in LDPE-vanillin film showed that the doodhpeda sample had clearly perceptible vanilla aroma, whereas biscuit had marginal aroma and skimmed milk powder did not have noticeable aroma. When viewed in the light of imparting desirable vanilla aroma, results of the study indicated that LDPE-vanillin film has better prospects as a packaging material for solid sweets with considerable fat content when stored under ambient conditions. The release of vanilla aroma was further confirmed by gas chromatography,mass spectrometery analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Mathematical Modeling of Microbial Growth in Packaged Refrigerated Orange Juice Treated with Chemical PreservativesJOURNAL OF FOOD SCIENCE, Issue 5 2001S.C. Andrés ABSTRACT Microbial flora of refrigerated orange juice was analyzed during storage at 10 °C and the effects of the following factors were discussed: 1) the previous washing process of the orange peel, 2) the different levels of the added preservatives (citric acid, ascorbic acid, potassium sorbate, sodium benzoate), 3) the gaseous permeabilities of the packaging film. Gompertz equation was applied to model molds and yeasts growth for the different treatments and packaging conditions. The washing procedure with sodium hypochlorite extend 2,3 d the storage life of the juice (time to reach microbial counts of 106 CFU/ml) in both packaging films. The use of organic acids and potassium sorbate or sodium benzoate (1.66,6.94 mM) led to storage life values > 11 d in polyethylene and > 20 d in the low gaseous permeability film, maintaining good sanitary conditions. [source] How to design perforated polymeric films for modified atmosphere packs (MAP)PACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2001Luciano ZanderighiArticle first published online: 12 APR 200 Abstract Increasing proportions of fresh produce are being sold in modified atmosphere packs (MAP) with the aim of preserving product quality longer and reducing freight costs. A rigorous theoretical analysis was made of the transport phenomena across packaging film (composite, perforated, etc.) in order to find out whether polymeric film will permit a stationary modified atmosphere (MA) inside the pack, and if so when, and to investigate the effect of the size and shape of the holes in the perforated film. The continuity equations of the pack, for all diffusing species, were written and solved for stationary conditions, with the boundary conditions that species not involved in metabolic processes do not diffuse across polymeric film. After a detailed analysis of the transport phenomena across both continuous and perforated film, and of the metabolic rate processes, it transpires that no stationary conditions compatible with any MA can be found for continuous film, owing to the permeation characteristics of the film and the rate of the metabolic processes. With perforated film it is possible to find, at least for certain metabolic process rates, a stationary state where a constant MA is maintained inside the pack. A proposal is given, provided the rate of the metabolic process is known, for the design of a pack in terms of polymeric materials and of the pinhole size. Two case studies, strawberry and cabbage, are presented and discussed, along with the optimization of the polymeric film and the size and length of the pinholes of the packs. Another point raised deals with the advantages of using perforated film and/or of making holes or openings along the edges where the polymeric film is welded. Copyright © 2001 John Wiley & Sons, Ltd. [source] Multilayered antimicrobial polyethylene films applied to the packaging of ground beefPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2001Jung-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] Effect of accelerated aging on the structure and properties of monolayer and multilayer packaging filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008P. A. Tarantili Abstract The effect of accelerated aging on the structure and properties of single, metalized, and multilayer films used in food packaging was studied through the exposure of specimens of those films to repeated aging cycles in a weather meter under the combined action of ultraviolet, humidity, and heat. The aged specimens were tested for their mechanical properties and water vapor transmission characteristics, and the results were compared to those obtained from the original specimens. The property changes introduced into the films by aging were further explored by attenuated total reflectance spectroscopy and differential scanning calorimetry in an attempt to correlate the changes in the properties with structural characteristics. The results showed that the films made of polypropylene (PP) underwent severe chain scission upon irradiation and lost mechanical properties but still retained their impermeability to water vapor. The metallic coating could not prevent PP from degrading, as it seemed to oxidize under the aging conditions. Therefore, the metalized film showed the same mechanical response as PP, but its water impermeability dropped dramatically. Polyethylene (PE) and poly(ethylene terephthalate) (PET) films showed modest decreases in their mechanical properties, which could be attributed to crosslinking reactions taking place with PE and to the increased ultraviolet stability of PET, respectively. On the other hand, the multilayer films presented a decrease in their mechanical properties according to those of their weak component, which would be expected for a composite structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] EFFECT OF POLYGODIAL ON MECHANICAL, OPTICAL AND BARRIER PROPERTIES OF CHITOSAN FILMSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2010L. MORENO-OSORIO ABSTRACT The mechanical, optical and barrier properties of chitosan films containing polygodial (0.0, 2.7, 13.9, 25.0 mg/g of chitosan) were studied. Water vapor permeability (WVP), tensile strength, percentage elongation at break, CIELab color parameters, hue angle and chroma of films were determined. Fourier transform infrared (FTIR) was also performed to determine functional group interaction between the matrix and polygodial added. The use of polygodial resulted in stronger films without losing their extensibility and with low WVP. Films became darker with yellow-green coloration with increasing polygodial concentration. Polygodial added to chitosan films did not have any interaction with the amino groups of chitosan as measured by FTIR. Polygodial as a natural dialdehyde can effectively be applied to enhance some physical properties of edible films prepared with chitosan. PRACTICAL APPLICATIONS There has been an increased interest in the study of edible,biodegradable packaging films during the last decade, offering an alternative and partial solution to the problem of accumulation of solid waste composed of synthetic inert polymers, and chitosan films has been studied with this purpose. Furthermore, replacing synthetic additives by natural compounds such us polygodial can be a suitable manner to improve some physical properties of those chitosan films. [source] Lethality of Listeria monocytogenes in Fully Cooked and Vacuum Packaged Chicken Leg Quarters During Steam PasteurizationJOURNAL OF FOOD SCIENCE, Issue 9 2003R. Y. Murphy ABSTRACT Fully cooked chicken leg quarters (160 g to 300 g) were injected to contain 107 to 108 colony-forming units (CFU)/g of a 5-strain Listeria monocytogenes culture. The inoculated leg quarters were vacuum-packaged in 0.08-mm-thick packaging films and then pasteurized at 96°C via steam. The heat transfer coefficient was about 760 W/m2 K in the steam cooker. Seven log10 (CFU/g) reduction of L. monocytogenes was achieved in about 22 min of steam treatment. Results from the inoculation tests agreed with the process lethality model prediction using the kinetic values that were obtained for the same product. This information helps industry to validate the lethality of L. monocytogenes in similar products during postcook pasteurization. [source] Mathematical Modeling of Microbial Growth in Packaged Refrigerated Orange Juice Treated with Chemical PreservativesJOURNAL OF FOOD SCIENCE, Issue 5 2001S.C. Andrés ABSTRACT Microbial flora of refrigerated orange juice was analyzed during storage at 10 °C and the effects of the following factors were discussed: 1) the previous washing process of the orange peel, 2) the different levels of the added preservatives (citric acid, ascorbic acid, potassium sorbate, sodium benzoate), 3) the gaseous permeabilities of the packaging film. Gompertz equation was applied to model molds and yeasts growth for the different treatments and packaging conditions. The washing procedure with sodium hypochlorite extend 2,3 d the storage life of the juice (time to reach microbial counts of 106 CFU/ml) in both packaging films. The use of organic acids and potassium sorbate or sodium benzoate (1.66,6.94 mM) led to storage life values > 11 d in polyethylene and > 20 d in the low gaseous permeability film, maintaining good sanitary conditions. [source] A comparative study of oxygen transmission rates through polymer films based on fluorescence quenchingPACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2010I. Siró Abstract Information on oxygen permeability through polymer films is essential for some applications, especially in food packaging where the control of oxygen levels can be critical in avoiding food spoilage. A permeability testing device using fluorescence-based optical oxygen sensing was developed as a potential new instrument for measuring the oxygen permeability of packaging films. The fluorescence-based permeability tester was validated against two existing commercial oxygen permeability measuring devices, the Mocon Ox-Tran 2/20 and PBI-Dansensor OPT-5000. Oxygen transmission rates (OTR) of polylactide (PLA) and nanoclay-reinforced PLA films, as well as polyethylene/poly(ethylene terephthalate) (PE/PET) and polypropylene/poly(ethylene terephthalate) (PP/PET) laminated films were determined at 23°C and 50% relative humidity using each of these instruments. No significant differences were observed between mean OTR values obtained by the fluorescence method and the corresponding values obtained using the OPT-5000 but significantly lower values were measured when using the Mocon Ox-Tran 2/20. In general, oxygen permeability data for the tested films were within the range of values found in the literature; however, in terms of further development, the fluorescence-based technique gave OTR with relatively high standard deviation compared to the commercial methods and equipment modifications to address this issue are considered desirable. Copyright © 2010 John Wiley & Sons, Ltd. [source] Mass transport studies of different additives in polyamide and exfoliated nanocomposite polyamide films for food industryPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2010David Antonio Pereira de Abreu Abstract The development of new food packaging films through the incorporation of nanoparticles, and the effect of the nanoparticles on the process of migration of the substances used in manufacturing the new films is expected to lead to an improvement in the shelf life of food and thus, consumer safety and health. In recent years, attention has focused on nanocomposites because these compounds often exhibit unexpected hybrid properties derived from synergistic reactions between nanoparticles and the polymeric matrix. The exfoliation of nanoclays in polyamide film provides a film with better barrier properties than that obtained through the intercalation of nanoclays. Migration of chemicals from food packaging into food may produce potential adverse health effects because of exposure to toxic compounds. The present study addressed the migration of caprolactam, 5-Chloro-2-(2,4-dichlorophenoxy)phenol (triclosan) and trans,trans-1,4-diphenyl-1,3-butadiene (DPBD) from polyamide and polyamide-nanoclays to different types of food simulants. The values for limit of detection (LOD) obtained for caprolactam, triclosan and DPBD was 0.5,mg/L, 0.02,mg/L and 0.01,mg/L, respectively. Furthermore, instrumental precision was evaluated through repeatability injections, resulting in relative standard deviations lower than 3.08%. Diffusion coefficients were calculated according to a mathematical model based on Fick's Second Law, and the results were discussed in terms of the parameters that may have the greatest effect on migration. The presence of polymer nanoparticles was found to slow down the rate of migration of substances from the matrix polymer into the food up to six times. Copyright © 2009 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 2007Isinay 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] The effect of high-pressure food processing on the sorption behaviour of selected packaging materialsPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2004C. Caner Abstract The sorption behaviour and flavour-scalping potential of selected packaging films in contact with food simulant liquids (FSLs) (ethanol and acetic acid solutions) were evaluated after high-pressure processing (HPP). The films used were monolayer polypropylene (PP), a multilayer (polyethylene/nylon/ethylene vinyl alcohol/polyethylene: PE/nylon/EVOH/PE), film and a metallized (polyethylene terephthalate/ethylene,vinyl acetate/linear low-density polyethylene: metallized PET/EVA/LLDPE) material. D-limonene was used as the sorbate and was added to each of the FSLs. After HPP treatment at 800,MPa, 10,min, 60°C, the amount of D-limonene sorbed by the packaging materials and the amount remaining in the FSL was measured. Untreated controls (1,atm, 60°C and 40°C) were also prepared. Extraction of the D-limonene from the films was performed using a purge/trap method. D-limonene was quantified in both the films and the FSL, using gas chromatography (GC). The results showed that D-limonene concentration, in both the films and the food simulants, was not significantly affected by HPP, except for the metallized PET/EVA/LLDPE. Significant differences in D-limonene sorption were found in comparison with the control pouches. The results also showed that changes in temperature significantly affected the sorption behaviour of all films. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development of a liquid extraction method and comparison with dynamic thermal stripping,thermal desorption (DTS,TD) method: sorption of D -limonene by flexible packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2004Cengiz Caner Abstract The sorption of D -limonene into polymeric structures in contact with food simulant liquids (ethanol and acetic acid solutions) was determined using two methods, liquid extraction (LE) and dynamic thermal stripping,thermal desorption (DTS,TD). The polymeric films studied were PP (polypropylene), PE/nylon/EVOH/PE (polyethylene/nylon/ethylene vinyl alcohol/polyethylene) and metPET/VA EVA/LLDPE (metallized polyethylene terephthalate/ethylenevinyl acetate/linear low density polyethylene). Our assessment showed that both LE and DTS,TD techniques are valuable procedures. LE was evaluated as an alternative method with the advantage of being a simplified process. It was possible to measure the amount of D -limonene in the polymers using both methods. Correlation between methods was >82% and for the single layer polymers >92%. The respective sorption values obtained by the two methods were also found to be in good agreement. LE is simple and rapid to perform and, in general, gives slightly lower results compared to DTS,TS sorption tests conducted with adequate food simulants. The results indicate that the liquid extraction method is an excellent technique for the determination of sorbate concentration in polymeric structures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effects of ozone exposure on the structural, mechanical and barrier properties of select plastic packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2002Banu 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] Influence of high-pressure processing on selected polymeric materials and on the migration of a pressure-transmitting fluidPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2002A. Schauwecker Abstract This study investigated the migration of 1,2-propanediol (PG) through selected food packaging films exposed to high-pressure processing (HPP). Pouches made from these materials were filled with 95% ethanol as a food-simulating liquid. These packages were then processed using a pilot-scale high-pressure food processor at 400, 600 and 827,MPa and 30, 50 and 75°C for 10,min. Controls were processed at similar temperatures and times, but at atmospheric pressure. To investigate any structural changes to these films during HPP, water was used as the food simulant at temperatures of 30, 75, 85, 90 and 95°C and at pressures of 200, 400, 690 and 827,MPa. No detectable PG migration into the polyester/nylon/aluminium (Al) polypropylene (PP) meal-ready-to eat (MRE)-type pouches was observed. PG migration into the nylon/ethylene vinyl alcohol (EVOH)/PE (EVOH) pouches was similar at 30, 50 and 75°C after 10,min under atmospheric pressure. However, PG migration into the EVOH pouches significantly decreased when treated with high pressure at 30, 50 and 75°C. At 75 and 50°C, the PG migration was significantly higher than the amounts detected at 30°C. Visible signs of delamination between the polypropylene (PP) and aluminum (Al) layers were observed in the MRE pouches processed at ,200,MPa and 90°C for 10,min. This delamination appeared to occur between the PP and Al layers. The differential scanning calorimetric analyses and Fourier transform infrared (FTIR) spectra were similar for the high-pressure treated pouches when compared to their respective controls. This indicated that there were no HPP-induced molecular changes to the treated pouches. Results from this study should be useful to HPP users for predicting PG migration trends and in deciding the selection of appropriate packaging materials for use under similar processing conditions. Copyright © 2002 John Wiley & Sons, Ltd. [source] Experimental and numerical study of sorption/diffusion of esters into polypropylene packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2002Laurent Safa Abstract The sorption and diffusion of four esters into polypropylene packaging films immersed in four different solutions have been studied by the FTIR method at 45°C. Kinetic curves have been generated for these systems to compute diffusion coefficients. The calculated results are discussed in terms of size and shape of diffusing molecules into a polymer film. Isovalues and profiles of liquid concentrations have been calculated by solving Fick's diffusion equation using a numerical method based on a two-dimensional finite element method. Copyright © 2002 John Wiley & Sons, Ltd. [source] Influence of co-monomer structure on properties of co-polyamide packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2002P. Scarfato Abstract In this work a series of co-polyamides were prepared by random polymerization of ,-caprolactam in presence of four different co-monomers at a percentage of 5% w/w, with the aim of verifying their suitability as film-forming materials. The effects of structural changes induced in the ,-caprolactam homopolymer by co-monomers were evaluated in both molten and solid states. Rheological tests in shear and elongational flow were performed to evaluate the processability of co-polyamides. Cast films were obtained and their thermal, mechanical and transport properties were evaluated to establish the performances of the co-polyamides in view of packaging applications. The results indicate that co-polyamide films having a partially aromatic structure display the best mechanical performances and show a significant improvement in barrier properties to gases compared to the homopolymer. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||