Apparatus and method for testing the permeability of materials to chemicals - Patents.com

Abstract

The present invention relates to a permeation test cell (4) for permeation testing of materials to chemicals. The permeation test cell (4) includes an upper body (20) with a first vent (40, 42, 44) and a lower body (28) with a second vent (46, 48, 50) for passing a first and a second gas stream. A perforated polytetrafluoroethylene (PTFE) grid (32) on a sample support plate (26) is placed under the test sample (24) to allow the passage of the contaminant (31) to the adsorbent tube. The test sample (24) with the contaminant (31) is placed in the permeation test cell (4). A second vent (50) is configured to be attached to the adsorbent tube for accumulation of the contaminant (31) permeating through the test sample (24). The permeation test cell (4) is configured to receive a weight (29) on the test sample (24) to force the permeation of the contaminant (31) through the test sample (24).

Description

[Technical field]

[0001] The invention herein relates generally to an apparatus and method for permeation testing of materials, and more particularly to an apparatus and method for permeation testing of materials used for protective ensembles against toxic chemicals, particularly chemical warfare agents or simulants thereof. [Background technology]

[0002] Toxic chemicals, especially chemical warfare agents (CWAs), are used in asymmetric warfare across borders and even within civilian populations. Many concerns exist regarding the exposure of personnel involved in handling these agents to CWAs or accidental incidents related to the exposure of personnel to these dangerous chemicals in vapor or liquid form. Efforts are being made continuously to advance the protective ensembles required for individuals to protect against toxic chemicals, especially CWAs. Evaluation of the functional performance of these protective ensembles needs to be carried out in different modes and configurations for the chemicals of interest.

[0003] There are many methods for measuring the permeation of toxic chemicals. One method for measuring the permeation of toxic chemicals, particularly CWAs or their simulants, is US Army Test Operating Procedure 08-2-501 (TOP). After testing with TOP, the contaminants that permeate through the protective material must then be measured using other conventional techniques. There are various techniques for measuring quantitative permeation density. Techniques include the use of chemical agent monitors (CAMs) or by desorption of sorbent tubes placed at the outlet in the lower body of the permeation test cell followed by evaluation by chromatographic or spectroscopic techniques.

[0004] TOP specifies the equipment and protocols for permeation measurements according to the permeation mode and configuration. The different permeation modes include static diffusion mode, dual flow mode and convective flow mode, which correspond to realistic permeation scenarios under the action of air flow. The permeation configurations include either liquid contamination vapor detection (L / V) configuration or vapor contamination vapor detection (V / V) configuration or liquid contamination liquid detection (L / L) configuration. The permeation configuration is based on the physical state of the chemicals for all the aforementioned modes.

[0005] FIG. 1A illustrates a sealed schematic diagram of the permeation test cell (1) as described in TOP. FIG. 1B illustrates an unassembled diagram of the permeation cell (1) for L / V and V / V configurations in static diffusion and dual flow modes. FIG. 2A illustrates an unassembled diagram of the permeation test cell (2) as described in TOP. FIG. 2B illustrates a sealed diagram of the permeation test cell (2) for L / V and V / V configurations in convective flow mode as described in TOP. FIG. 3 illustrates the test conditions in the L / V configuration according to TOP, and FIG. 4 illustrates the test conditions in the V / V configuration according to TOP. One of the disadvantages of TOP is that different devices and methods are required for the evaluation of permeation depending on the different modes and configurations of permeation operation.

[0006] TOP also covers permeation test methods for protective materials in a liquid contaminant / liquid detection (L / L) configuration that uses an exclusion test mode to evaluate the resistance of protective materials to toxic chemicals, especially CWA or their simulants, under external pressure. The exclusion method is important to evaluate protective materials under external pressures that are realistic scenarios in which a person wearing protective gear touches a contaminated surface or holds a contaminated object. According to TOP, there are contamination density differences between permeation tests in the traditional L / V, V / V and L / L exclusion permeation modes. According to TOP, the contamination density is 10 g / m in the L / V configuration for all three modes. 2 This is 10 cm 2In the L / L configuration in qualitative exclusion mode, a single drop of a single chemical agent of 4 μL (for HD) or 5 μL (for GA / GB / GD / VX) is applied to the center of the swatch sample. In the L / L exclusion mode, the area is approximately 1.0 in due to the contact area of ​​the weight. 2 is defined as 1 psi or 70.2 g / cm 2 Approximately 7.75 g / m 2 In both modes, the contamination density is sufficient to mimic a real transmission scene.

[0007] In the exclusion test mode, an external pressure of 1 psi is applied to material contaminated with a single chemical agent droplet (5 mg neat or 8 mg concentrated). Figure 5 illustrates the exclusion test apparatus and method. The apparatus consists of a cylindrical stainless steel weight (10) (454 gms, 2.87 cm diameter) applied onto a test sample (14) carrying a chemical agent droplet (16). Colorimetric detection paper (12) (M8 chemical agent detection paper) is placed under the test sample (14) to determine the breakthrough time. The main disadvantage of using the TOP method is that the evaluation of materials using the exclusion method is purely qualitative in nature. Furthermore, the TOP method measures breakthrough time in contrast to the penetration density of the chemical agent.

[0008] Therefore, in view of the aforementioned limitations, a need exists for an apparatus and method to enable quantified testing of contaminant permeation through protective materials in a variety of configurations and modes representing different environmental controls. Summary of the Invention [Problem to be solved by the invention]

[0009] A general object of the present invention is to devise an apparatus and method for permeation testing of protective materials in different modes to allow quantification of the permeation density of chemical contaminants.

[0010] Another object of the present invention is to provide an apparatus and method for permeation testing that provides high confidence in the protective capabilities of the material being tested while minimizing variability in test results on the same specimen at low testing costs.

[0011] Another object of the present invention is to provide an apparatus and method for permeation testing to determine the resistance of materials used in protective ensembles, such as body suits, gloves, shoes, masks, haversacks, body bags, etc., to toxic chemicals, particularly chemical warfare agents or simulants thereof.

[0012] It is yet another object of the present invention to provide an apparatus and method for permeation testing by utilizing the same apparatus under different configurations and modes to simulate different environmental scenarios that affect the permeation of contaminants through protective materials. [Means for solving the problem]

[0013] This Summary is provided to introduce aspects related to an apparatus and method for permeation testing of materials for chemical contaminants, which aspects are further described in the Detailed Description below. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0014] In order to achieve the above-mentioned object, in one aspect of the present invention, a permeation test cell is disclosed. The permeation test cell may be designed to include an upper body and a lower body. The upper body may be provided with one or more first vents for passing a first gas flow, and the lower body may be provided with one or more second vents. A contaminant may be placed on the upper side of the test sample, and the test sample may be disposed between the upper body and the lower body. In one aspect of the present invention, one of the second vents of the lower body may be configured to have an adsorbent tube attached thereto for accumulating the contaminant permeated through the test sample. For accumulation of the test sample in the adsorbent tube, a second gas flow may be passed through one of the second vents and released through the other one of the second vents.

[0015] In one embodiment, the permeation test cell may include a sample support plate positioned above the lower body for placement of a test sample, and a compression plate positioned below the upper body to hold the test sample in place.

[0016] In another embodiment, the permeation test cell may include a plurality of O-rings positioned in contact with the sample support plate and the compression plate to prevent leakage of contaminants from the edge of the test sample. A first O-ring may be positioned in contact with the compression plate from above, a second O-ring may be positioned in contact with the compression plate from below, a third O-ring may be positioned in contact with the sample support plate from above, and a fourth O-ring may be positioned in contact with the sample support plate from below.

[0017] In one embodiment of the invention, all of the first vents may be closed to determine the permeability of the contaminant through the test sample in the absence of air flow, and a second gas flow may be fed across one of the second vents used as an inlet and released through one of the second vents used as an outlet for the purpose of accumulating the contaminant in the adsorbent tube.

[0018] In one embodiment, when an air stream flows along the test sample, a first vent may be closed and a first gas flow may be provided through one of the first vents used as an inlet and released through one of the first vents used as an outlet for purposes of determining the permeability of a contaminant through the test sample. A second gas flow may be provided across one of the second vents used as an inlet and released through one of the second vents used as an outlet for purposes of accumulating contaminants in the sorbent tube.

[0019] In another embodiment of the invention, when an air flow flows across the test sample, two of the first vents positioned parallel to one another may be closed and a gas flow may be supplied through the other first vent used as an inlet and released through one of the second vents used as an outlet, for the purpose of accumulating contaminants in the adsorbent tube to determine the permeability of the contaminants through the test sample.

[0020] According to another embodiment of the invention, when an air flow flows along the test sample, one of the first vents positioned at the top of the upper body may be closed and a first gas flow may be supplied through two of the first vents positioned parallel to each other for the purpose of determining the permeability of a contaminant through the test sample.

[0021] According to another embodiment of the present invention, the permeation test cell may include a weight positioned on the test sample for the purpose of exerting pressure on the contaminant to force the permeation of the contaminant through the test sample.

[0022] In another embodiment of the invention, the permeation test cell may include a perforated polytetrafluoroethylene (PTFE) grid placed under the test sample to allow passage of contaminants to the adsorbent tube.

[0023] In another embodiment of the present invention, the permeation test cell may include a first PTFE layer placed between the weight and the test sample for the purpose of isolating contaminants from the weight.

[0024] In another embodiment of the invention, the permeation test cell may include a ring of colorimetric detection paper placed around the periphery of the test sample between the perforated PTFE grid and the test sample to determine leakage of contaminants from the edges of the test sample.

[0025] In another embodiment of the invention, the permeation test cell may include a second PTFE layer placed between the test sample and the perforated PTFE grid to block permeation of contaminants through the test sample and determine leakage of contaminants from the edge of the test sample into the adsorbent tube.

[0026] These and other aspects of the embodiments herein will be better understood and appreciated when considered in conjunction with the following description and the accompanying drawings. It should be considered, however, that the following description, while indicating preferred embodiments and details thereof, is given for purposes of illustration and not for purposes of limitation. Changes and modifications can be made within the scope of the embodiments described herein without departing from the spirit thereof. The embodiments herein include all such modified embodiments.

[0027] The accompanying drawings are used to provide a further understanding of the present invention. Such accompanying drawings illustrate embodiments of the present invention which are used to explain the principles of the present invention. The embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numbers indicate similar elements. It should be noted that reference to "an" or "one" embodiment in the present invention does not necessarily refer to the same embodiment, but rather means at least one. [Brief description of the drawings]

[0028] [Figure 1(A)]FIG. 1(A) illustrates a sealed schematic diagram of a conventional test cell for measuring permeation in L / V configuration for dual-flow and static diffusion modes and V / V configuration in dual-flow mode according to the prior art. [Figure 1(B)] FIG. 1(B) illustrates an unassembled schematic diagram of a conventional test cell for measuring permeation in L / V configuration for dual-flow and static diffusion modes and V / V configuration in dual-flow mode according to the prior art. [Figure 2(A)] FIG. 2(A) illustrates an unassembled schematic diagram of a conventional test cell for measuring permeation in L / V and V / V configurations for convective flow mode, according to the prior art. [Figure 2(B)] FIG. 2(B) illustrates a sealed schematic diagram of a conventional test cell for measuring permeation in L / V and V / V configurations for convective flow mode, according to the prior art. [Diagram 3] FIG. 3 illustrates test conditions for a prior art L / V configuration according to TOP. [Figure 4] FIG. 4 illustrates test conditions in a V / V configuration according to the prior art according to TOP. [Diagram 5] FIG. 5 illustrates a schematic diagram of a conventional test setup for measuring transmission in the L / L configuration for exclusion mode, according to the prior art. [Figure 6(A)] FIG. 6(A) illustrates a sealed schematic diagram of a permeation test cell according to one embodiment of the present invention. [Figure 6(B)] FIG. 6(B) illustrates an unassembled schematic diagram of a permeation test cell for measuring permeation in L / V and V / V configurations for static diffusion, dual flow and convective flow modes according to one embodiment of the present invention. [Figure 6(C)] FIG. 6(C) illustrates a sealed schematic diagram of a permeation test cell in L / V configuration for static diffusion mode, according to one embodiment of the present invention. [Figure 6(D)] FIG. 6(D) illustrates a sealed schematic diagram of a permeation test cell in L / V and V / V configuration for dual flow mode according to one embodiment of the present invention. [Figure 6(E)] FIG. 6(E) illustrates a sealed schematic diagram of a permeation test cell in L / V and V / V configurations for convective flow mode according to one embodiment of the present invention. [Figure 7(A)] FIG. 7(A) illustrates a schematic diagram of a permeation test cell in an L / L configuration for quantitative exclusion mode in different implementations according to an embodiment of the present invention. [Figure 7(B)] FIG. 7(B) illustrates a schematic diagram of a permeation test cell in an L / L configuration for quantitative exclusion mode in different implementations according to an embodiment of the present invention. [Figure 7(C)] FIG. 7(C) illustrates a schematic diagram of a permeation test cell in L / L configuration for quantitative exclusion mode in different implementations according to an embodiment of the present invention. [Figure 7(D)] FIG. 7(D) illustrates a schematic diagram of a permeation test cell in L / L configuration for quantitative exclusion mode in different implementations according to an embodiment of the present invention. [Figure 8] FIG. 8 illustrates test conditions for a quantitative exclusion test according to one embodiment of the present invention. [Figure 9] FIG. 9 illustrates the properties of an activated carbon sphere (ACS) based three-ply composite and an activated carbon fabric (ACF) based three-ply composite tested against chemicals of interest in accordance with one embodiment of the present invention. [Figure 10] FIG. 10 illustrates the average permeation and standard deviation results for a number of replicates of ACS and ACF test samples, according to one embodiment of the present invention. [Figure 11] FIG. 11 illustrates average permeation results obtained from a quantitative exclusion method for a fixed number of replicates of ACS and ACF test samples, according to one embodiment of the present invention. [Figure 12] FIG. 12 illustrates a flow diagram illustrating a method for permeation testing of materials to chemicals under pressure in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Various features of the present invention are fully described with reference to non-limiting embodiments. The embodiments described herein do not include details of commercial and well-known components and their methods of use in order to simplify the description. The examples described herein should not be considered as limiting the scope of the embodiments described herein, but are intended to facilitate an understanding of how the embodiments may be practiced by those skilled in the art.

[0030] The present invention relates to an apparatus and method for permeation testing materials against chemicals in different permeation modes and configurations to simulate different environmental controls. Figure 6(A) illustrates a sealed view of a permeation test cell (4). As shown in Figure 6(A), the permeation test cell (4) may include an upper body (20) and a lower body (28). The upper body (20) and the lower body (28) may be provided with one or more first vents (40, 42, 44) for passing a first gas flow through the upper body (20). The lower body (28) may be provided with one or more second vents (46, 48, 50) for passing a second gas flow through the lower body (28).

[0031] FIG. 6(B) illustrates an unassembled schematic diagram of the permeation test cell (4). The permeation test cell (4) may include a compression plate (22) positioned below the upper body (20) and a sample support plate (26) positioned above the lower body (28). A contaminant (31) may be placed on the upper side of the test sample (24). The test sample (24) may be placed on the sample support plate (26). The test sample (24) is held in place by the compression plate (22). The permeation test cell (4) may further include a number of O-rings (21, 23, 25, 27) positioned between the upper body (20) and the lower body (28). The O-rings may be used to prevent leakage of the contaminant (31) from the edge of the test sample (24). A first O-ring (21) may be positioned in contact with the compression plate (22) from above. A second O-ring (23) may be positioned in contact with the compression plate (22) from below. A third O-ring (25) may be positioned in contact with the sample support plate (26) from above. A fourth O-ring (27) may be positioned in contact with the sample support plate (26) from below.

[0032] 6(A), the upper body (20) and the lower body (28) of the permeation test cell (4) may be sealed with cell lugs after the test sample (24) with contaminant (31) is placed between the upper body (20) and the lower body (28). In one implementation, the permeation test cell (4) is made of stainless steel 316 to reduce the risk of corrosion resulting from the use of highly corrosive and toxic chemicals, particularly chemical warfare agents or simulants.

[0033] 6(C) illustrates a sealed view of the permeation test cell in the L / V configuration for static diffusion mode. The first vents (40, 42, 44) of the permeation test cell (4) may be closed to determine the permeability of the contaminant (31) through the test sample (24) in the absence of airflow. The permeation density of the material can then be quantified for scenarios in which airflow does not affect the permeation of the contaminant (31) through the test sample (24).

[0034] FIG. 6(D) illustrates a sealed view of the permeation test cell in the L / V and V / V configuration for the dual flow mode. The first vents (40) of the permeation test cell (4) may be closed. A first gas flow may be fed through one of the first vents (42, 44) used as an inlet and discharged through one of the first vents (42, 44) used as an outlet for the purpose of determining the permeability of the contaminant (31) through the test sample (24) when the air flow flows along the test sample (24). One of the second vents (50) of the lower body may be configured to have an adsorbent tube attached. The adsorbent tube accumulates the contaminant (31) that has permeated through the test sample (24). A second gas flow can be provided across one of the second vents (46, 48) used as an inlet and released through one of the second vents (46, 48) used as an outlet for the purpose of accumulating the contaminant (31) within the adsorbent tube, and the permeation density of the material can be quantified for scenarios in which air flowing past the test sample (24) affects the permeation of the contaminant (31).

[0035] FIG. 6(E) illustrates a sealed view of the permeation test cell in the L / V and V / V configurations for convective flow mode. The first vents (42, 44) of the permeation test cell (4) may be closed. A first gas flow may be provided through the first vent (40) which is used as an inlet for the purpose of determining the permeability of the contaminant (31) through the test sample (24) when the air flow impinges on the test sample (24). One of the second vents (46, 48, 50) of the lower body may be configured to receive an adsorbent tube. The adsorbent tube accumulates the contaminant (31) that has permeated through the test sample (24). The permeation density of the material can then be quantified for scenarios in which air flowing across the test sample (24) affects the permeation of the contaminant (31).

[0036] The test parameters depicted in Figures 3 and 4 with the TOP may be used in different configurations for the various modes of the invention as illustrated in Figures 6(C), 6(D) and 6(E). The contamination density may also be maintained in a similar manner to that in a conventional TOP. Additionally, the contamination density may be varied depending on the requirements of the permeation test conditions.

[0037] The permeation test cell (4) may be used in a quantitative exclusion mode to measure permeation under the action of an external pressure. Figures 7(A), 7(B), 7(C) and 7(D) illustrate the permeation test cell in an L / L configuration for the quantitative exclusion mode in different implementations. For use in the exclusion mode, the permeation test cell (4) may include a weight (29) placed on a contamination (31) present on the test sample (24). The weight (29) applies pressure to the contamination (31) to force the permeation of the contamination (31) through the test sample (24). The weight may be made of stainless steel grade 316 to reduce the risk of corrosion resulting from the use of highly corrosive and toxic chemicals, particularly chemical warfare agents or simulants.

[0038] As illustrated in FIG. 7(A), the permeation test cell (4) may include a perforated polytetrafluoroethylene (PTFE) grid (32) placed under the test sample (24). The perforated PTFE grid allows the passage of the contaminant (31) into the adsorbent tube. A stainless steel weight (29) may be placed on the test sample (24) to apply external pressure on the contaminated protective material. The permeation cell (4) may be sealed to allow the permeation of the contaminant in a liquid contaminant vapor detection (L / V) configuration for a quantitative exclusion mode. The permeated contaminant vapor swept by the dry air flow in the lower body may be adsorbed in an adsorbent tube attached to one of the second vents (50) of the lower body. A quantitative determination of the permeation may be measured by desorption of the contaminant from the adsorbent material inside the adsorbent tube with a solvent and analyzed using chromatography or any other quantitative technique. FIG. 8 illustrates the test conditions for the quantitative exclusion test.

[0039] Some of the test methods performed to measure the permeation of contaminants through materials are described below in the non-limiting examples. Figure 9 illustrates the testing of two materials, namely an activated carbon sphere (ACS) based three-layer composite and an activated carbon fabric (ACF) based three-layer composite, against one compound of interest that is a CWA, Sarin (GB). The permeation test was carried out for 6 hours. More than 20 replicates of each composite were tested, along with a minimum of 10 control samples. The test method used was based on the developed quantitative exclusion test in L / V configuration as described above. The test parameters mentioned in Figure 8 were utilized. Figure 10 illustrates the average permeation and standard deviation results for the tested test samples. It was observed that the standard deviation (SD) of the amount of contaminant permeated was large, especially for the ACS composite, which is believed to be due to the non-uniformity within the replicate test samples. It is clear that the present invention provides an improvement over conventional test methods to allow for the quantification of the amount permeated.

[0040] There is a possibility that contaminants (31), instead of passing through the test sample (24), will travel around the edge of the test sample (24) and reach the lower body (28) despite the O-ring clamping on the edge. This leakage will invalidate the test method. To prevent this situation, the integrity of the permeation test cell (4) can be checked to ensure that there is no leakage of contaminants (31) through the edge of the test sample (24) into the sorbent tube.

[0041] As illustrated in FIG. 7(B), the permeation test cell (4) may include a first PTFE layer (33) disposed between the weight (29) and the test sample (24). The first PTFE layer (33) isolates the contaminant (31) from the weight (29). The first PTFE layer (33) prevents any chemical reaction between the weight (29) and the contaminant (31). The first PTFE layer (33) may also allow the contaminant (31) to be spread evenly over the test sample (24).

[0042] As illustrated in Figure 7(C), a ring of colorimetric detection paper (35) may be placed between the perforated PTFE grid (32) and the test sample (24). The colorimetric detection paper (35) may be placed around the periphery of the test sample (24). The colorimetric detection paper determines leakage of contaminant (31) from the edge of the test sample (24). If the contaminant passes into the edge instead of through the swatch sample, the colorimetric detection paper will change color.

[0043] Additionally, a characterization sample may be included before every batch of test samples to verify the integrity of the permeation test cell (4), i.e., for a given contaminant and protective material, the contaminant permeates through the test sample (24) and not through the edge of the test material (24). The purpose of this characterization sample is to demonstrate that the contaminant (31) is not wicked through the edge of the test sample (24). As illustrated in FIG. 7(D), the permeation test cell (4) may include a second PTFE layer (34). The second PTFE layer (34) may be placed between the test sample (24) and the perforated PTFE grid (32). The second PTFE layer (34) may block the permeation of the contaminant (31) through the test sample (24) and allow for the determination of leakage of the contaminant (31) from the edge of the test sample (24) into the sorbent tube. If any contamination is measured in the adsorbent tube, the test will fail for that material and contaminant combination.

[0044] Various quality controls were incorporated into the test protocol for the permeation test, including contamination purity analysis, sorbent tube efficiency, positive control samples, negative control samples, contamination load verification, leakage testing through the edges of the test samples, and analytical controls, which are described in the non-limiting examples below.

[0045] The swatches were cut with a sharp steel die and press. For the protective body suit, equal numbers of swatches are taken from the front, back, sleeves and legs. A gas-tight syringe may be used to spike the liquid contaminant onto the sample swatch. A calibrated balance may be used for verification of the weight of the spiked contaminant. Solvents used in the test were of chromatographic grade.

[0046] As part of the quality control of the system, the efficiency of Fluka ORBO™ 609 Amberlite® XAD®-2 (20 / 50) 400 / 200 mg sorbent tubes was determined. To determine the efficiency of the sorbent tubes for a particular chemical, solutions of 5 μg, 10 μg, 100 μg, 500 μg, and 5 mg of the chemical in 100 μL of solvent were spiked separately onto the sorbent material in the sorbent tube. The larger area of ​​the sorbent tube was wetted. The total mass adsorbed fit within the calibration curve of the analytical instrument and was within the range of concentrations that the sorbent tube was expected to perform at. A stream of dry air at a rate of 300 mL / min was passed through the sorbent tube for 6 hours at approximately 32° C. After 6 hours, the sorbent material was removed from the sorbent tube and extracted with 20 mL of ethyl acetate for approximately 30 minutes, and a quantitative determination was performed by fitting the data within the calibration curve based on a standard solution of the chemical. Other solvents may be used as appropriate for the particular contaminant and / or analytical technique. The extractant was analyzed using a gas chromatography-mass spectrometry (GC-MS) (not shown) with a quantification limit of approximately 1 μg / mL. Other analytical tools may be used to achieve improved detection limits.

[0047] Another quality control parameter is the purity of the contaminants. The use of low purity contaminants can lead to incorrect results. In another embodiment of the invention, the purity of the contaminants can be checked using analytical techniques such as Nuclear Magnetic Resonance (NMR) spectroscopy (not shown).

[0048] In another implementation of the invention, the reproducibility of the gas-tight syringe can be checked using a gravimetric method: the target amount to be drawn into the gas-tight syringe can be accurately weighed by drawing into a vial using a calibrated electronic balance (not shown) and the dispersion can be recorded.

[0049] In another implementation of the invention, the temperature of an incubator (not shown) may be set to approach 32°C or any other desired value and verified using a calibrated temperature recorder (not shown). The stainless steel permeation test assembly may be allowed to equilibrate for at least 24 hours prior to each test. Temperatures may be recorded every minute and dispersion noted. Other temperatures may be used as required by the test conditions.

[0050] Positive control samples may be required before or at the same time as testing the actual samples. The purpose of the positive control sample is to ensure the performance of the test method and equipment used. Under controlled conditions, materials with known permeation density / butyl rubber for HD and materials with known permeation density / neoprene for nerve gases (GB, GD, GA, VX) can be employed as positive control samples.

[0051] Negative control samples may also be required to be run prior to or at the same time as testing the actual samples. The negative control sample could be the same as the positive control sample, but should be completely free of contamination. The purpose of the negative control is to demonstrate the proper functioning of the test apparatus and method, as well as the absence of any cross-contamination that may arise from the tool or other test cells. No contaminants are measured above the limit of quantification in any of the negative control samples.

[0052] The analytical method used herein includes a calibration curve generated by quality control samples to increase the reliability of the data. The limit of quantification is determined by the standard sample with the lowest concentration in the calibration curve. The calibration curve is expressed as R 2 The values ​​must be linear within the range 0.995 to 0.999.

[0053] In another implementation of the invention, to assess the upper limit of bias and to account for sample loss due to the interaction of contaminants with the first PTFE layer (33), the second PTFE layer (34), and the perforated PTFE grid (32).... The second PTFE layer (34) can be spiked with contaminants and placed on the perforated PTFE grid (32). The contaminants can be covered with the first PTFE layer (33) and a weight (29) placed on it. The sample goes through the same testing process, but without the sorbent tube or air flow. After a certain duration, both the PTFE layers (33, 34) and the perforated PTFE grid (32) can be extracted independently and the sample loss can be checked by comparing the quantity of extracted contaminants with the original contaminant amount. The sum of the extraction results of both the PTFE layers (33, 34) and the perforated PTFE grid (32) is expected to be equal to the original contaminant level. The difference is attributed to potential losses during the entire process.

[0054] In the second round of testing, the permeation of 5 mg of VX was measured through the 3-ply ACS and 3-ply ACF composites illustrated in Figure 9. Using the quantitative exclusion method described above, permeation measurements were calculated. Permeation in samples below the limit of quantification or not detected in the analysis is marked "ND." For each of these tests, the sorbent tubes were extracted in solvent for 30 minutes before GC-MS testing. Figure 11 illustrates the average permeation results obtained from the quantitative exclusion method for a fixed number of replicates of the ACS and ACF test samples.

[0055] The present invention may be used for permeation through any of air-impermeable, semi-permeable and air-permeable protective materials. The implementation of the present permeation test method with different accessories increases the reliability of the protective ability of the material and reduces operational testing costs by using the same device under different quantitative measurement configurations and modes. The method and device also evaluate performance under conditions that reflect more realistic use in different environmental scenarios, such as mimicking the forces associated with touching a contaminated surface or gripping a contaminated object. The present invention provides a quantitative exclusion test method to indicate that a material can provide suitable protection for approximately 6 hours under external pressure.

[0056] 12, a method for permeation testing of materials against chemicals under pressure is described with reference to flow chart 1200. The flow chart illustrates a method for permeation testing of contaminants in a liquid contaminant vapor detection (L / V) configuration for quantitative exclusion mode, according to an embodiment of the present invention. It should be noted that in some variant implementations, the steps may be performed in any order, or perhaps substantially simultaneously, or may be modified to perform methods that combine other components of the present invention, depending on the embodiment of the present invention.

[0057] In block 1202, to begin a permeation test of the test sample in the permeation test cell, a perforated PTFE grid may be placed on the sample support plate to allow passage of contaminants permeating through the test sample towards the sorbent tube mounted in the lower body. In block 1204, the test sample may be securely placed in the permeation test cell. The test sample may be placed on the perforated PTFE grid on the sample support plate. In block 1206, a contaminant may be applied onto the test sample, which may be held in place above the test sample by a compression plate. The contaminant may be present in liquid form. In block 1208, a weight may be applied to the test sample and the test cell may be sealed to apply pressure and determine the effect of external pressure on the permeation of the contaminant through the test sample. In block 1210, the contaminant permeating through the test sample may be accumulated in the sorbent tube and measured using chromatographic techniques for quantitative determination of the permeation density of the test sample.

[0058] The detailed description set forth above in connection with the accompanying drawings is intended as a description of various embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. Each embodiment described in the present disclosure is provided merely as an example or illustration of the present disclosure and should not necessarily be construed as preferred or advantageous over other embodiments.

[0059] Any combination of the above features and functionality may be used in accordance with one or more embodiments. In the above specification, the embodiments have been described with reference to many specific details that may vary from implementation to implementation. Therefore, the specification and drawings should be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indication of the scope of the present disclosure and what the applicant intends to be the scope of the present disclosure is the literal and equivalent scope of the set of claims originating from this application in the specific form from which such claims issue, including any subsequent amendments.

Claims

1. a permeation test cell (4) for testing the permeation of chemical contaminants through a material, an upper body (20) having one or more first vents (40, 42, 44) for passing a first gas flow and a lower body (28) having one or more second vents (46, 48, 50) for passing a second gas flow, the upper body (20) and the lower body (28) being sealed together after placing a contaminant (31) on the upper side of a test sample (24) placed between the upper body (20) and the lower body (28); A permeation test cell comprising: one of the second vents (50) of the lower body is configured to receive an adsorbent tube for accumulating the contaminants (31) permeated through the test sample (24); The permeation test cell comprises: a weight (29) on the test sample (24) for applying pressure on the contaminant (31) to force transmission of the contaminant (31) through the test sample (24); and a perforated polytetrafluoroethylene (PTFE) grid (32) placed under the test sample (24) to allow passage of the contaminant (31) into the adsorbent tube; a permeation test cell (4) configured to accommodate the

2. 2. The permeation test cell (4) of claim 1, comprising a compression plate (22) positioned below the upper body (20) and a sample support plate (26) positioned above the lower body (28), the test sample (24) being disposed between the sample support plate (26) and the compression plate (22).

3. 3. The permeation test cell (4) of claim 2, further comprising a plurality of O-rings (21, 23, 25, 27) positioned in contact with the sample support plate (26) and the compression plate (22), the plurality of O-rings (21, 23, 25, 27) preventing leakage of the contaminant (31) from the edges of the test sample (24).

4. 4. The permeation test cell (4) of claim 3, wherein the first O-ring (21) is positioned in contact with the compression plate (22) from above, the second O-ring (23) is positioned in contact with the compression plate (22) from below, the third O-ring (25) is positioned in contact with the sample support plate (26) from above, and the fourth O-ring (27) is positioned in contact with the sample support plate (26) from below.

5. 5. A permeation test cell (4) as claimed in any one of claims 1 to 4, wherein all of the first vents (40, 42, 44) are closed to determine the permeability of the contaminant (31) through the test sample (24) in the absence of air flow, and the second gas flow is supplied across one of the second vents (46, 48) used as an inlet and released through one of the second vents (46, 48) used as an outlet, for the purpose of accumulating the contaminant (31) in an adsorbent tube.

6. 5. A permeation test cell (4) according to any one of claims 1 to 4, wherein, when an air flow flows along the test sample (24), the first vent (40) is closed and the first gas flow is supplied through one of the first vents (42, 44) used as an inlet and released through one of the first vents (42, 44) used as an outlet, for the purpose of determining the permeability of the contaminant (31) through the test sample (24).

7. 5. The permeation test cell (4) of claim 1, wherein the first vents (42, 44) are closed and the first gas flow is supplied through the first vent (40) used as an inlet and released through one of the second vents (46, 48, 50) used as an outlet, for the purpose of accumulating the contaminant (31) in the adsorbent tube when an air flow flows across the test sample (24) to determine the permeability of the contaminant (31) through the test sample (24).

8. 5. A permeation test cell (4) according to any one of claims 1 to 4, comprising a weight (29) placed on the contaminant (31) on the test sample for the purpose of applying pressure on the contaminant to induce permeation.

9. 9. The permeation test cell (4) of claim 8, further comprising a first PTFE layer (33) disposed between the weight (29) and the test sample (24) for the purpose of isolating the contaminant (31) from the weight (29).

10. 2. The permeation test cell (4) of claim 1, including a ring of colorimetric detection paper (35) positioned around the test sample (24) between the perforated PTFE grid (32) and the test sample (24), the colorimetric detection paper determining leakage of the contaminant (31) from the edge of the test sample (24).

11. 11. The permeation test cell (4) of claim 10, including a second PTFE layer (34) positioned between the test sample (24) and the perforated PTFE grid (32), wherein the second PTFE layer (34) blocks permeation of the contaminant (31) through the test sample (24) and determines leakage of the contaminant (31) from an edge of the test sample (24) into the adsorbent tube.

12. A method for testing the permeation of a chemical contaminant through a material comprising: providing a permeation test cell (4) comprising an upper body (20) with one or more first vents (40, 42, 44) for passing a first gas flow and a lower body (28) with one or more second vents (46, 48, 50) for passing a second gas flow; providing a sample support plate (26) above said lower body (28) for placing a test sample (24) thereon, and a compression plate (22) below said upper body (20) for holding the test sample in place; placing the test sample (24) between the sample support plate (26) and the compression plate (22); applying a contaminant (31) to the top side of the test sample (24); attaching an adsorbent tube to the second vent (50) for accumulation of the contaminants (31) permeated through the test sample (24); sealing the upper body (20) of the test cell with the lower body (28); A method comprising:

13. 13. The method of claim 12, including providing a plurality of O-rings (21, 23, 25, 27) for preventing leakage of the contaminant (31) from the edges of the test sample (24).

14. 14. The method of claim 13, comprising: positioning the first O-ring (21) in contact with the compression plate (22) from above, positioning the second O-ring (23) in contact with the compression plate (22) from below, positioning the third O-ring (25) in contact with the sample support plate (26) from above, and positioning the fourth O-ring (27) in contact with the sample support plate (26) from below.

15. 13. The method of claim 12, comprising closing all of the first vents (40, 42, 44) to determine the permeability of the contaminant (31) through the test sample (24) in the absence of air flow, and supplying a second gas flow from one of the second vents (46, 48) used as an inlet and discharging it through one of the second vents (46, 48) of the lower body.

16. 13. The method of claim 12, comprising closing the first vents (40), supplying the first gas flow through one of the first vents (42, 44) used as an inlet, and releasing the first gas flow through one of the first vents (42, 44) used as an outlet, to determine the permeability of the contaminant (31) through the test sample (24) as an air flow flows along the test sample (24).

17. 17. The method of any one of claims 12 to 16, comprising closing the first vents (42, 44) and supplying the first gas flow through the first vent (40) used as an inlet and releasing it through one of the second vents (46, 48, 50) used as an outlet, for the purpose of accumulating the contaminant (31) in the adsorbent tube as an air flow passes across the test sample (24) to determine the permeability of the contaminant (31) through the test sample (24).

18. 16. The method of any one of claims 12 to 15, comprising positioning a perforated polytetrafluoroethylene (PTFE) grid (32) under the test sample (24) to allow passage of the contaminant (31) into the adsorbent tube.

19. 16. The method of any one of claims 12 to 15, comprising positioning a weight (29) on the test sample (24) for the purpose of applying pressure on the contaminant (31) to force transmission of the contaminant (31) through the test sample (24).

20. 20. The method of claim 19, including positioning a first PTFE layer (33) between the weight (29) and the test specimen (24) for the purpose of isolating contaminants (31) from the weight (29).

21. 19. The method of claim 18, comprising positioning a ring of colorimetric detection paper (35) around the periphery of the test sample (24) between the perforated PTFE grid (32) and the test sample (24) to determine leakage of the contaminant (31) from the edge of the test sample (24).

22. 21. The method of claim 20, comprising positioning a second PTFE layer (34) between the test sample (24) and the perforated PTFE grid (32) to block permeation of the contaminant (31) through the test sample (24) and determine leakage of the contaminant (31) from an edge of the test sample (24) into the adsorbent tube.

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