Evaluation and optimization of seal behaviour through solid contamination of heat‐sealed films

A method is presented to apply solid powder/granulate contamination (ground coffee and blood powder) in between the heat conductive seals of flexible packaging materials. A response surface method is tested and validated to optimize seal strength of heat conductive sealing with and without solid contamination. In this study, a maximal seal strength is defined as optimal. Using these methods, three typical packaging films with varying seal layer composition (metallocene linear low‐density polyethylene (LLDPE), plastomer, and sodium ionomer) are maximized towards contaminated seal strength. Contamination caused a decrease in seal strength and narrowed down the process window (seal temperature and time combinations) in which at least 90% of the maximal strength is obtained. The influence of seal layer composition on the clean and solid (ground coffee and blood powder) contaminated seal performance (seal strength, process window, and leak tightness) was evaluated. The film with the plastomer‐based seal layer outperformed the other films with respect to the width of the process window. It also reached a higher seal strength and a higher amount of leak tight seals (evaluated with the dye penetration test) after optimization. The hot tack test was evaluated as predictive test for the contaminated seal strength. The results of this study do not support an indicative relationship.     

Thermal transitions and heat‐sealing of glycerol‐plasticized whey protein films

Transparent, flexible whey protein‐based edible films plasticized with glycerol were produced by wet (solution‐casting) and dry (twin‐screw extrusion followed by compression‐molding) processes. The relationship between the thermal transitions and the heat‐sealability of the whey protein‐based edible films was investigated. Differential Scanning Calorimetry showed the existence of endothermic peaks with an onset transition temperature of 156.3 ± 1.4°C for both the solution‐cast and extruded films. Films were heat‐sealed using an impulse heat‐sealer at an effective jaw pressure of 293.31 kPa, a voltage of 15 V and a cooling time of 4 s. Various impulse times, ranging from 1.5 to 2.5 s, were used to heat‐seal the films. A thermocouple was used to measure the heat‐sealing temperatures at each impulse time. Heat‐sealing temperatures ranged between 126.1 ± 9.0 and 204.0 ± 5.4°C for the shortest and longest impulse times, respectively. Seal strengths were determined using an Instron Universal Testing Machine. Film thickness appeared to have an effect on seal strength; higher strengths were achieved for thinner films, which, in this case, were the solution‐cast films. Thicker (extruded) films required a longer minimum impulse time to achieve a heat‐seal. The highest seal strength (433.07 ± 39.37 N/m) was obtained with solution cast films (thickness of 0.13 ± 0.01 mm) sealed with an impulse time of 2 s (164.6 ± 5.1°C). Impulse times above 2.5 s (204.0 ± 5.4°C) resulted in degradation of both solution‐cast and extruded films. Copyright © 2009 John Wiley & Sons, Ltd.     

Practical Approach in Developing Desirable Peel–Seal and Clear Lidding Films Based on Poly(Lactic Acid) and Poly(Butylene Adipate‐Co‐Terephthalate) Blends

In this research, poly(lactic acid) (PLA) blend with poly(butylene adipate‐co‐terephthalate) (PBAT) were selected to fabricate peelable lidding films. In general, blending PLA with PBAT results in hazy films; however, desirable low haze films (<10%) could be achieved in this study by designing proper blend composition and cast film process under optimum conditions. Based on various blends containing PBAT ranging from 15 to 30% by weight, it could be seen that a PBAT/PLA blend of 20/80 showed desired optical and peel–seal property, which had a haze of <10% and low peel strength in an easy‐peel characteristic. It was also observed that not only the blend composition but also the film thickness could influence both optical and peel–seal behaviours because the bulk morphology and surface irregularities of the films could vary by changing films' thicknesses. Thus, cast extruded pristine and PBAT/PLA (20/80) blend films of three different thicknesses (20, 35 and 50 μm) were studied. Peel–seal behaviour and optical properties of these films were examined. An I‐peel test (180°) of films sealed on PLA sheet (thickness of ~350 μm) with different interfacial sealing temperature illustrated failure mechanism of four types, i.e. tearing, partial tearing, cohesive and adhesive failure. Based on this study, the PBAT/PLA of 20/80 wt% films with thickness of 20 μm can be used as easy‐peel lidding film sealed with PLA container. Such PBAT/PLA blend films possess a low haze of ~4% and a low peel strength of 8–10 N/15 mm at a broad range of interfacial sealing temperature of 76–105°C. Copyright © 2017 John Wiley & Sons, Ltd.     

Non‐destructive packaging seal strength analysis and leak detection using ultrasonic imaging

This study investigated the effectiveness of ultrasonic imaging for non‐destructive assessment of seal strength in 335 ml polymeric trays. In the first part of this study, the experimental procedures involved filling sample trays with beef enchilada, then sealing at temperatures of 170–260°C for 5 s at 3 bar. Ultrasonic measurements were conducted using an immersion technique in pulse/echo mode. The captured signal amplitudes of the reflections from the samples were digitized and analysed to construct high‐resolution C‐scan ultrasonic images of the seals. The acquired data were statistically analysed for each sample and used as a basis for comparison with the seal (peel) strength, measured as the energy at break. The energy at break was obtained from destructive peel strength analysis, performed using a tensile testing frame. In the second part of this study, ultrasonic imaging was used to predict the performance of the heat sealer used to fabricate the test trays by comparing the seal quality of each of the four quadrants of the samples trays. This study also investigated the minimum channel leak size that could be detected using this ultrasound system. The results of the peel strength analyses showed that a direct correlation exists between seal strength and sealing temperature (170–227°C). Results of the ultrasonic imaging showed that the statistical scatter in the signal amplitude decreased as the sealing temperature increased. This reduction in the scatter of the signal amplitudes indicated a trend of increasing uniformity in the fusion of the two seal faces. Between 170°C and 193°C, sharp changes in the scatter were observed; however, little change was noted for sealing temperatures greater than 193°C, indicating that 204°C could be a minimum recommended sealing temperature. To confirm this result, a drop test analysis was performed on trays filled with beef enchilada and sealed at temperatures of 170–260°C for 5 s at 3 bar. Results of this drop test confirmed that 204°C was the minimum critical sealing temperature. Based on these results, ultrasonic imaging appeared to offer a promising non‐destructive method for the prediction of seal quality in polymeric trays, sealing equipment monitoring and identification of channel leaks ?20 µm in diameter, and is comparable with the more established destructive peel strength analytical method. Copyright © 2003 John Wiley & Sons, Ltd.     

The influence of defect and temperature on the fatigue behaviours of Al‐Si‐Cu‐Mg‐Ni alloy

High‐cycle fatigue (HCF) properties of two Al‐Si‐Cu‐Mg‐Ni alloys with different defect sizes named as alloys A (smaller ones) and B (bigger ones) were investigated at 350°C and 425°C, respectively. The results indicate that fatigue strengths of both alloys decrease as the temperature increases. Fatigue cracks originated from pores and oxide films at both temperatures. They propagated preferentially through cracked matrix at 350°C and debonded interface and grain boundary at 425°C. Alloy A exhibits higher fatigue life and fatigue strength than alloy B at 350°C due to its smaller pore sizes. However, it has slightly worse fatigue properties than alloy B at 425°C because the fatigue crack initiation is controlled by oxide film at this temperature and is not affected by its size. This indicates that there is a transition of predominant initiation site from pores to oxide films when the temperature increases. The fatigue strength estimated through defect size is consistent with the experimental results at 350°C, while unsuitable at 425°C.     

Heat Sealing measurement by an innovative technique

To obtain a proper heat seal is an important requirement in packaging, since seal failure is a more frequent cause of product deterioration than the package itself. Different kinds of seal, such as peelable or non‐peelable, can be obtained by changing the conditions under which a material is sealed. Therefore, identifying these conditions is very important. A new technique, the m ethod for m easuring t emperature of m elting s urface (MTMS), was used to predict the strongest peelable seal on various packaging commercial films. The temperature of the seal interface was measured using a thermocouple. The time–temperature profile, which was obtained by means of a thermocouple, was electronically processed so as to obtain the derivatives of the profile. The inflection point, also called the fusion point, was located on these profiles. This inflection point is associated with the physical change of the state of the material being sealed. The inflection point analysis was done using two different methods: (a) the MTMS method, based on the second derivative of temperature data with time; (b) ‘Table Curve’ software, based on non‐linear regression. This technique was successfully used to evaluate widely used packaging films such as LDPE, HDPE, LLDPE and CPP. The inflection point for these films was identified and the seal strength was verified using a universal testing machine. This method appears to be applicable to design the strongest peelable heat seals for many packaging materials. It also seems to have promise as a method of process measurement and validation for heat seal processes. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of film tension and contamination on the seal quality of flexible food packaging films made of polypropylene and low density polyethylene blends containing talc filler

Seal integrity and seal strength are important requirements in the heat sealing of flexible packaging. In this article, the influence of talc compounds and different process parameters, such as film tension and contamination on the sealant films consisting of polypropylene and low-density polyethylene blend were investigated. According to the results, increasing the talc ratio from 0% wt to 30% wt positively influenced both hot and cold seal strength. Among different polymer blends having same talc ratio, the sample having the lowest melt flow index (2.84 dg/min at 230°C and 2.16 kg) showed the highest cold seal strength with 9.07 N/25 mm. On the other hand, in the samples with higher melt flow indexes, less seal integrity issues were observed in the presence of contaminants. Elevated film tensions from 0 to 0.4 N/mm² enhanced the seal strengths significantly at the seal initiation temperatures of each film. However, this situation changed at higher operating temperatures due to the increased orientation and brittleness. Besides, in the presence of contaminant coffee particles at the seal interphase, high film tensions adversely affected the seal integrity since the average leakage increased 2.7% for samples A and B, and 7.4% for sample C. In summary, it has been shown that talc incorporation can improve seal strength, high MFI can fill the gaps at the seal interphase and the high levels of film tension (above 0.16 N/mm²) during sealing as well as the contamination need to be avoided to ensure integrity sealing.     

Seal bond characterization of laminated plastic food cups by scanning electron and optic microscopes

Heat seals of laminated semi‐rigid food cups were evaluated to characterize the seal bond. Laminated lidding material was sealed at temperatures of 160–180°C to thermoformed cups. Various seal regions of the cups with different ultrasonic signal strengths (%) were sectioned at the rim and examined using optical and scanning electron microscopes (SEM). Ultrasonic signals were able to pinpoint seal defects; however, the magnitude of the signals did not relate to the actual seal condition or seal quality affected by the sealing process. This was attributed to the very short seal width and non‐parallel surface of the heat seal, which possibly resulted in signal loss by reflection and scattering from the seal surface. C‐scan of ultrasound, SEM and optical microscopic images provided the information that the heat‐sealing process was unstable, due to insufficient and non‐uniform heat‐seal temperature or pressure, misalignment of the sealing jaws or non‐parallel sealing or cutting unit configuration. Copyright © 2004 John Wiley & Sons, Ltd.     

An Empirical Investigation into the Influence of Sealing Crimp Geometry and Process Settings on the Seal Integrity of Traditional and Biopolymer Packaging Materials

This article presents the results of investigations to determine how process settings and crimp geometry affect the seal strength and integrity of traditional polyolefin and biopolymer flexible packaging materials. The results show agreement with previous studies where temperature and dwell time are found to be the dominant factors for both polyolefin and biopolymer films. Pressure and crimp geometry are shown to be secondary factors in the process, up to the point of squeezing the film into molecular contact. In general, it is shown that biopolymers exhibit similar sealing characteristics to more traditional films. Regarding the sealing crimp geometry, it is shown that the crimp pitch has little or no effect on sealing integrity for films with gauges between 25 and 40 µm. However, for the same gauge material, crimp angles more than 80° offer the greatest potential to gain higher seal strengths. It is further shown that with the cellulose and polylactic acid films tested, a higher seal strength can be produced with crimp pitches of 2 mm and lower. Also presented are some more general implications for guiding the selection of sealing crimp geometry and their usage with biopolymers. Copyright © 2012 John Wiley & Sons, Ltd.     

Stress Evolution With Temperature in Titanium‐Rich NiTi Shape Memory Alloy Films

Abstract: The effect of deposition temperature on residual stress evolution with temperature in Ti‐rich NiTi films deposited on silicon substrates was studied. Ti‐rich NiTi films were deposited on 3″ Si (100) substrates by DC magnetron sputtering at three deposition temperatures (300, 350 and 400 °C) with subsequent annealing in vacuum at their respective deposition temperatures for 4 h. The initial value of residual stress was found to be the highest for the film deposited and annealed at 400 °C and the lowest for the film deposited and annealed at 300 °C. All the three films were found to be amorphous in the as‐deposited and annealed conditions. The nature of the stress response with temperature on heating in the first cycle (room temperature to 450 °C) was similar for all three films although the spike in tensile stress, which occurs at ～330 °C, was significantly higher in the film deposited and annealed at 300 °C. All the films were also found to undergo partial crystallisation on heating up to 450 °C and this resulted in decrease in the stress values around 55–60 °C in the cooling cycle. The stress response with temperature in the second thermal cycle (room temperature to 450 °C and back), which is reflective of the intrinsic film behaviour, was found to be similar in all cases and the elastic modulus determined from the stress response was also more or less identical. The three deposition temperatures were also not found to have a significant effect on the transformation characteristics of these films such as transformation start and finish temperatures, recovery stress and hysteresis.     

Influence of substrate temperature and film thickness on the structure of reactively evaporated In2O3 films

Indium oxide films 25–550 Å thick were reactively evaporated at an oxygen pressure of about 0.27 Pa and at a substrate temperature between room temperature and 400°C. The dependence of the structure of the films on the substrate temperature and on the film thickness was studied using transmission electron microscopy and electron diffraction. It was found that thick films (about 550 Å) were amorphous at room temperature, partially crystallized at 50–125°C and crystalline at 150–400°C. The crystallinity of the films deposited at 150–250°C also depended markedly on the film thickness. Very thin films about 25 Å thick were quasi-amorphous, but with increasing film thickness the amorphous phase transformed into a crystalline phase.The thermal transformation of the amorphous films after deposition was also studied. Amorphous films about 550 Å thick deposited at room temperature and 100°C crystallized at 230°C and 210°C respectively.     

Attenuated total reflection fourier transform infrared spectroscopy towards disclosing mechanism of bacterial adhesion on thermally stabilized titanium nano-interfaces

Titanium is widely used as medical implant material and as condenser material in the nuclear industry where its integrity is questioned due to its susceptibility to bacterial adhesion. A systematic investigation on the influence of thermally (50–800 °C) stabilized titanium (TS-Ti) nano oxide towards bacterial adhesion was carried out. The results showed that below 350 °C significant bacterio-phobicity was observed, while above 500 °C significant affinity towards bacterial cells was recorded. Conventional characterization tools such as HR-TEM and XRD did not provide much insight on the changes occurring on the oxide film with heat treatment, however, attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) of the surface showed significant changes in the spectral pattern as a function of increasing heat treatment. It was observed that elevated OH, N–H and C=O groups and rutile titania on the TS-Ti oxide films led to higher affinity for bacterial adhesion. On the other hand low temperature TS-Ti nanooxide films (<350 °C) showed high C–H groups and decreased OH groups on their surface, which possibly contributed towards their bacterio-phobicity. The TS-Ti nanooxide film grown at 50 °C was observed to be the most efficient anti-bacterial adhesion interface, while the 800 °C interface was the one showing highest affinity towards bacterial adhesion. This study confirms the successful application of ATR-FTIR technique for nano-oxide film characterization and towards understanding the variations in bacterial interaction of such nano interfaces.     

Preparation of ceria films by spray pyrolysis method

The deposition of CeO₂ films on fused-silica substrates by spray pyrolysis of a water–ethanol solution of a cerium nitrate precursor has been studied. Polycrystalline films have been obtained at a substrate temperature of 300–450°C after annealing of the deposit in air at temperatures in the range 350–500°C. It has been established that the best uniform ceria films with nanometric scale grains are prepared at a substrate temperature of 400°C with 0.5 h annealing of the deposit at 500°C. At lower spraying temperatures large CeO₂ crystallites have been observed on the film surface along with the fine grains. When the substrate temperature exceeds 400°C, numerous cracks caused by thermal stresses appear in the films.     

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

This 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.     

Evaluation of a laboratory‐scale pressure differential (force/decay) system for non‐destructive leak detection of flexible and semi‐rigid packaging

This study evaluated the capabilities of a bench‐top non‐destructive pressure differential leak tester using 355 ml polyethylene terephthalate/ethylene vinyl alcohol/polypropylene (PET/EVOH/PP) trays. This evaluation was done by monitoring the equipment's force/decay responses to leaks, changes in the package headspace volume and differences in the seal strength of 986 sample trays. Leak detection evaluation was done using artificially created channel leaks (10–200 µm) in the sealing areas and pinholes (5–50 µm) in the lids of the polymeric trays. Seal strength evaluation included the ability of the equipment to identify non‐leaking but weak seals and the extent to which the pressure differential unit affected good seals during a normal test run. The results showed that the equipment had a detection limit of 40 µm for channel leaks 6 mm in length and 15 µm for pinholes. The results also showed that the pressure differential unit caused a 9% reduction in the seal strength of the tested packages. However, peel strength analysis and distribution testing showed that this reduction in seal strength did not compromise the integrity of 99% of the packages tested. Results showed that the equipment could also detect weak but non‐leaking seals that had potential to lose integrity during transportation and retail handling. The results of this study could be used to determine the capabilities and limitations of a non‐destructive pressure differential bench‐top leak testing device intended for food packaging quality control. Copyright © 2002 John Wiley & Sons, Ltd.     

High‐Temperature Shape Memory Effect in Ti‐Ta Thin Films Sputter Deposited at Room Temperature

Ti‐Ta based alloys are potential high‐temperature shape memory materials with operation temperatures above 100 °C. In this study, the room temperature fabrication of Ti‐Ta thin films showing a reversible martensitic transformation and a high temperature shape memory effect above 200 °C is reported. In contrast to other shape memory thin films, no further heat treatment is necessary to obtain the functional properties. A disordered α″ martensite (orthorhombic) phase is formed in the as‐deposited co‐sputtered Ti₇₀Ta₃₀, Ti₆₈Ta₃₂ and Ti₆₇Ta₃₃ films, independent of the substrate. A Ti₇₀Ta₃₀ free‐standing film shows a reversible martensitic transformation, as confirmed by temperature–dependent XRD measurements during thermal cycling between 125 °C to 275 °C. Furthermore, a one‐way shape memory effect is qualitatively confirmed in this film. The observed properties of the Ti‐Ta thin films make them promising for applications on polymer substrates and especially in microsystem technologies.     

Effect of ovenproof plastic films on the quality of spotted rose snapper (lutjanus guttatus) fillets during frozen storage

Spotted rose snapper (Lutjanus guttatus) fillets packed in two polymer films, polyamide 6,6 (PA66) and polyethylene terephthalate (PET), were stored at ?20°C for a period of 120 days. Films were tested for melting temperature (PA66 253–257°C and PET 252–255°C), oxygen transmission rate [PA66 51.8 ± 12.9cm³/(m²·24h·atm) and PET 152.7 ± 0.2cm³/(m²·24h·atm)] and water vapor transmission rate [PA66 17.8 ± 1.7g/(m²·24h) and PET 6.5 ± 0.2g/(m²·24h)]. Sensory analyses (firmness, flavour and appearance) were performed at 0, 30, 60, 90 and 120 days of storage after baking the fillets in the same storage bags. For raw fillets, their water‐holding capacity (WHC), total aerobic counts (TAC), pH, trimethylamine (TMA) and shear‐force resistance were measured at the same periods. Sensory analyses after baking showed no differences between the fillets packaged in the two films. The WHC, TAC, pH and TMA values in both products were kept within accepted limits. The fillets packed in PET showed a significant increase in firmness (shear‐force resistance) during the first 60 days of storage and then a decrease at 90 days due to dehydration through the film seals. Over the same period, the fillets packed in PA66 showed no significant changes in firmness. In this study, it was demonstrated that it is possible to develop a ready‐to‐bake fish fillet product by using ovenproof films for packaging during storage. Copyright © 2006 John Wiley & Sons, Ltd.     

Paper‐derived stoneware ceramics: Improvement of properties by calendering and evaluation of pyroplastic deformation behaviour

Paper‐derived ceramics are a new approach to produce thin, lightweight ceramic structures. These ceramics are derived from preceramic papers produced in a paper technological process. The amount of inorganic filler (e. g. stoneware) in the paper is increased up to 85 wt‐%. By firing at high temperatures the cellulose fibres are pyrolized and the inorganic content is sintered. One part of the technological process to produce papers is calendering. A calender consists of two rolls, between which the paper is rolled under pressure. By calendering the paper thickness is reduced and the surface of the paper is improved. Different calender parameters (pressure and temperature) are applied to the preceramic paper and ceramic properties like strength, density and surface roughness are investigated. The strength of paper‐derived stoneware ceramics can be improved by 125% to over 185 MPa by optimizing the calender process. Additionally paper‐derived stoneware ceramics were fired at 1180°C, 1200°C and 1220°C for 1 and for 2 hours at different support distances (10–150 mm) in order to determine the dependence of pyroplastic deformation on support distance. The results show a linear increase between maximum deformation and support distance by 1 hour dwell and a polynomic at 2 hours dwell. Furthermore the Pyroplastic Index (PI) was evaluated according to recent literature. The Pyroplastic Index was correlated to the amorphous content of the differently fired samples. With longer dwell and/or higher temperature the content of amorphous phase increases which lowers the bulk viscosity and supports the pyroplastic deformation. These investigations should give a direction for using paper‐derived stoneware ceramics for special design applications. Paper‐derived ceramics can be systematically deformed in many possible ways to achieve specific shapes.     

Investigation of the resistance welding of multilayers aluminum-coated polymer complexes used as envelopes of vacuum insulation panels

Vacuum Insulation Panels (VIPs) are thermal insulators consisting of a core material enveloped by a high barrier film or envelope required to maintain the vacuum.Multilayered aluminum-coated polymer complex are the common barrier envelopes of VIPs used as high performance thermal insulation in building applications. The multilayer complex is sealed to maintain the vacuum for a long period of time. From a mechanical and barrier properties standpoint, sealed edges represent the weak point of the envelope assembly. This paper investigates the influence of sealing parameters on the properties of the weld. T-peel and tensile tests in combination with Optic Microscopy observations were used to characterize the heat seals. A minimum seal initiation temperature of 115 °C was identified for the studied complex. Peel strength increased sharply to reaching a maximum value at (140 °C–5 s), which considered as optimum temperature–time couple. Above and beyond these values, a gradual decrease was observed and microscopic images indicate the appearance of roll generated by the expelled polymer mass from the center to the edges of the weld which strongly impacts the morphology of the welded area.     

Development of a system for measurement of permeability of aroma compounds through multilayer polymer films by coupling dynamic vapour sorption with purge‐and‐trap/fast gas chromatography

A system for measurement of permeability of aroma compounds through laminated polymer films was constructed by combining dynamic vapour sorption (DVS) with purge‐and‐trap/fast gas chromatography (P&T–fGC). Data validation was achieved by measuring the permeability of limonene across an HDPE film (film C) and comparing the permeation data with the literature values. The general applicability of this system, as well as its potential for simultaneous measurement of permeability of multiple aroma compounds, was demonstrated by measuring the permeability of limonene and ethyl butyrate as single permeants or as co‐permeants under different environmental conditions (at 25°C, 30°C or 35°C and 0% or 75% RH) through three different multilayer polymer films (film A, HDPE/EVOH/HDPE/HDPE; film B, HDPE/nylon/HDPE/HDPE; film C, HDPE/HDPE). The results showed that the aroma barrier performance of plastic films was determined by the polymer composition and was affected by various factors, such as temperature and the presence of other co‐permeants. Simplicity, speed and accuracy were some of the attractive features of this system, which indicates its potential as a useful tool that could be applied in the food industry for screening or selection of appropriate packaging materials for specific applications. Copyright © 2004 John Wiley & Sons, Ltd.