Oily Environment Research Articles

Barnacle-inspired amphipathic high strength adhesives under-water/oil

Adhesives designed for bonding in liquid environments have a broad application prospect. In general, amphiphilic polymer structures are important research objects for underwater bonding. And in the study of underwater adhesives, it was found that they can quickly dispel or absorb interfacial water and form reliable bulk strength and adhesion strength. However, achieving strong adhesion in both water-based and oily environments poses a significant challenge. In this work, an adhesive inspired by barnacles that can meet the bonding requirements in both water-based and oily environments has been prepared. Hydrophilic (polyethylene glycol (PEG)) main chains and hydrophobic (1-Octadecyl thiol (ODT)) side chains are simultaneously integrated into the polyurethane structure. Different from the past, hydrophobic and hydrophilic segments are included in the hard segment and soft segment microregion, respectively; At the same time, both hydrophilic and hydrophobic chain segments have strong crystallization, which greatly strengthens the driving force of molecular segments migration and phase separation compared with ordinary hydrophilic/hydrophobic structures. Water-based and oil-based solvents drive hydrophilic and hydrophobic molecular chains to diffuse to the surface, respectively, which enhances the adhesive strength to hydrophilic and hydrophilic surfaces, respectively. In comparison to the adhesion strength observed in air, the adhesion strength of the adhesive to polymethyl methacrylate (PMMA) increases by 1.72 times in oil environments (from 1.02 to 1.75 MPa). Similarly, the adhesion strength to aluminum (Al) increases by 2.23 times under water (from 1.82 to 4.04 MPa). These findings suggest that the regulation strategy for polymer chains employed in this study holds great potential for advancing adhesive performance in diverse environments.

Polar modification‐enhanced interfacial compatibility for high‐performance rubber blends

AbstractThe blending of different elastomers can greatly broaden the application range of rubber materials. However, due to the poor compatibility between polar elastomers and non‐polar elastomers, severe phase separation occurs during the blending process, which severely degrades their processing performance and mechanical properties. In this paper, we prepared SBR‐P/XNBR blends by emulsion blending polar modified styrene‐butadiene rubber (SBR‐P) latex with carboxylated nitrile rubber (XNBR) latex. The effects of the blending ratios on the vulcanization behavior, mechanical strength, dynamic mechanical properties, and oil resistance of the rubber compounds were studied. Experimental results showed that the mechanical strength and oil resistance of the modified SBR‐P/XNBR blends are significantly higher than the unmodified SBR and XNBR blends. The dynamic mechanical analysis curve results of the rubber compounds showed that SBR‐P has good compatibility with XNBR. With the increasing addition of XNBR, the oil resistance of the rubber compounds improves, and the solvent adsorption is reduced by over 60%.This study proposes a solution for utilizing non‐polar rubbers, which are typically not oil‐resistant, in oily environments. The proposed solution enables the preparation of composites with excellent mechanical properties in such environments.

Assessing BeO, MgO, and CaO nanocages for a facile detection of hazardous phosgene oxime along with DFT calculations

The current density functional theory (DFT) work was done for assessing beryllium oxide, magnesium oxide, and calcium oxide nanocages; assigned by BeO, MgO, and CaO, for a facile detection of hazardous phosgene oxime (CX) substance in order to approach novel materials developments for the hazardous substances detections. The results indicated meaningful formations of the complexes in an adsorption strength order; CX@BeO < CX@MgO < CX@CaO, resulting a suitable recovery time. Further conductance rate analyses were done to see the features of detection processes, in which measuring the molecular orbitals variations indicated the detectable formation of complexes. The values of energy gap could stand for managing the detection processes. Additionally, analyzing the impacts of watery and oily environments showed the suitability of watery medium for reaching a better stability of models in comparison with the oily medium.

Implement Industrial 4.0 into process improvement: A Case Study in Zero Defect Manufacturing

This study describes in detail step-by-step implementation of quality improve- ment activities in mechanical processing plants. Describe how to imple- ment quality 4.0 technologies in DMAIC (Define-Measure-Analysis-Improve- Control) phases. As well as using statistical formulas, experimental design in data analysis at each phase of DMAIC. This study proposes to use Quality 4.0 Technology in product quality improvement activities in mechanical product processing factories with the aim of becoming zero defect manufacturing. The results of the research found are repair rate reduced from 600 PPM monthly to 0 PPM, processing capacity increased from Cpk1.02 to Cpk2.56, reduce time for inspection product from 702 hours per year (calculated to save USD 2106 per year), reduce the amount of repair products by 196 products per year (calculated in terms of money is reduced by 917 USD per year) and reduce 1 roughing stage (calculated in terms of cost reduction about 171288 USD per year). The roughness dimension has reduced measurement time by about 364 hours per year (save 1092 USD per year). Processing digital signals from sen- sors in an oily environment is a big challenge for researchers. Improving the security of digital data is also a limitation of this study. This study proposes a model to apply statistical hypothesis testing methods to analyze real data collected from each machining stage and perform each job according to each corresponding DMAIC phase of the model. In addition, digital processing tech- niques and computer vision techniques are also deployed in the improve phase to complete the goal of improving the semiautomatic production stage to the automatic production stage.

Synergistic improvement on both the oil-resistance and heat-resistance performance of a single-component acrylic pressure-sensitive adhesive

Traditional pressure-sensitive adhesive (PSA) materials are prone to failure under oily and high-temperature environments. Herein, a new series of acrylate copolymers, poly(methoxyethyl acrylate - butyl acrylate - ethyl acrylate - acrylic acid - (N-methoxy acrylamide)), were developed as single-component acrylic PSAs. The oil-resistance and heat-resistance of acrylic PSAs were improved remarkably through three strategies: 1) using the polar monomer, methoxyethyl acrylate (MOEA), to replace the commonly used monomer of 2-ethylhexyl acrylate (EHA), as the dominant ingredient in PSA to increase oil-resistance, 2) innovatively introducing N-methoxy acrylamide (NMOAM) as a new internal crosslinking monomer, thereby maintaining the stability of the PSA system at ambient conditions, while crosslinking with acrylic acid (AA) at high temperature curing conditions to obtain a single-component PSA, 3) owing to the synergistic effects of polarity and crosslinking which occurred during curing process, the oil-resistance and heat-resistance of PSAs enhanced greatly. The molecular weight of the acrylate copolymers and viscosity of the copolymer solutions were regulated by using xylene as a co-solvent to balance the adhesive properties of the acrylic PSAs. Effects of MOEA and NMOAM concentration on adhesive properties were investigated in detail. Results showed that the maximum tack of 12 #, shear strength of >168 h, and 180° peel resistance of 23.47 ± 0.07 N/24 mm could be obtained when 60 wt% of MOEA and 3 wt% of NMOAM were used for the PSA preparation. The obtained PSA tapes were able to maintain excellent adhesive properties even in harsh environments, such as high temperature and oily environment. This work demonstrates that how the comprehensive properties of acrylic PSAs can be improved thereby facilitating their application in the automobile industry, including bundling wire harnesses in car engine rooms or mounting attached parts to tanks.

Comparative transcriptomic and lipidomic analysis of oleic environment adaptation in Saccharomyces cerevisiae: insight into metabolic reprogramming and lipid membrane expansion

With staggering progress on genetic manipulation strategies, Saccharomyces cerevisiae is becoming an ideal cell factory for the de novo biosynthesis of lipid compounds. However, due to their hydrophobicity, lipids tend to be accumulated within intracellular spaces and cause a high burden on cell activity and induce product inhibition effect, which ultimately restricted the lipids biomanufacturing for industrial application. Herein, an oleic acid stress (OAS) model was applied for the long-time domestication of BY4741 cells, and a subclone of A-22 was obtained through a series of acclimation (0.1% glucose and 0.2% oleic acid), showing increased accumulation of both biomass and intracellular lipid droplets compared to WT. Comparative transcriptome analysis indicated that compared to fatty acid metabolism, most transcripts enriched in the pathways of glucose catabolism (glycolysis and citrate cycle) and lipid synthesis (phospholipid and sterol) were down-regulated under OAS. While interestingly, most the above transcripts tended to be ‘restored’ in adapted strain A-22. In addition, for physical adaptation, significant increase of phosphatidylcholines was identified by lipidomic analysis, which probably caused the subsequent subcellular expansion of peroxisomes and lipid droplets as observed in the adapted strain, since phosphatidylcholines are the major constituent of their membranes. The present study systematically investigated both the phenotype change and molecular mechanism on adaptation of S. cerevisiae towards oily environment. Detailed information on functional transcripts may provide novel rational modification targets to reinforce the hydrophobic lipids biosynthesis within S. cerevisiae engineered cell factory.

Characterization of polylactic-epoxidized natural rubber/modified cellulosic fiber biocomposites with different silane coupling agents

A purpose of this research was to investigate a potential of two differently modified cellulosic fibers for applying as reinforcing fillers in polylactic acid (PLA) and modified epoxidized rubber (ENR) base of biocomposites. Coupling agents including 3-(trimethoxysilyl) propyl methacrylate and (3-aminopropyl) trimethoxysilane were used in order to modify cellulosic fibers. These fibers were compounded with PLA-modified ENR (modified by bisphenol A diglycidyl ether) in an internal mixer and fabricated to composite sheets using a compression molding, respectively. The formulations of biocomposites were designed by weight ratio of PLA (85%): modified ENR (5%): the cellulosic fiber (10%). Accordance with the results of mechanical property analysis of their biocomposites, the modifications of cellulosic fibers with both silane types significantly improved flexural, hardness and impact properties of PLA-modified ENR based biocomposites. However, the methacrylate-silane modified cellulosic fiber provided the greatest increase in flexural properties while the amino-silane modified cellulosic fiber resulting in the highest value of hardness and impact resistance of all biocomposites. Oil absorption test of biocomposites was also investigated in this research in order to evaluate its possibility to use under oily environment. After 168 hours of experiment, the amino-silane modified composite exhibited the highest oil absorption among all materials. This result indicated the most improvement of hydrophobicity of modified cellulosic fiber by (3-aminopropyl) trimethoxysilane.

All-organic fluorine-free superhydrophobic bulk material with mechanochemical robustness and photocatalytic functionality

Artificial superhydrophobic surface has attracted extensive research interests and versatile applications have been demonstrated. However, such surfaces feature mechanical and chemical susceptibility and lose superhydrophobicity after oily contamination. So far, developing a simple method to fabricate superhydrophobic material featuring mechanochemical robustness along with oil fouling resistance remains challenging. Here we describe a straightforward approach to fabricate superhydrophobic bulk composite materials with photocatalytic functionality that simultaneously feature mechanochemical robustness and oil fouling resistance. The obtained bulk material shows mechanical robust superhydrophobicity throughout its whole volume and maintains excellent water repellency after exposure to highly corrosive liquids and organic solvents. Notably, the bulk material possesses photocatalytic self-cleaning functionality, which enables the elimination of the oily contaminations on the substrate surface, leading to the regeneration of its superhydrophobicity. The robust superhydrophobicity and functionality provide the developed bulk material potential applications in harsh chemical and oily environments where robustness is required.

High dielectric acrylonitrile-butadiene rubber with excellent mechanical properties by filling with surface-modified barium/strontium inorganic functional powders

Acrylonitrile-butadiene rubber (NBR) filled with surface-modified barium titanate (MBT), strontium titanate (MST) and barium strontium titanate (MBxS1−xT) was used to prepare the polymer dielectrics. BxS1−xT powders (x = 0.8, 0.7, 0.5 and 0.3) were synthesized via solid-state method. The crystal structure was observed by X-ray diffraction. The morphology and particle size of different powders were characterized by scanning electron microscopy (SEM). The contact angle test verified the hydrophobicity of the inorganic functional powders modified with bis-(γ-triethoxysilylpropyl)-tetrasulfide (KH845-4) improved obviously. The ratio of the dispersive solid surface tension and polar solid surface tension between inorganic filler and NBR matrix became closer after surface modification. The NBR/MBT/MST and NBR/MBxS1−xT systems were designed to improve the dielectric properties and enhance the mechanical properties. The curing characteristic of all NBR gums was tested. The dispersion of surface-modified functional filler in NBR was observed great according to the images of SEM. The mechanical properties of NBR/filler composites reinforced markedly compared with the neat NBR. For dielectric properties, the NBR/MB0.7S0.3T composites had the highest dielectric constant and the NBR/MST composites had the lowest dielectric loss factor at room temperature. They were suitable to be applied under the different frequency in oily environment for a long time. The oil resistance of all composites was also tested.

Enhancement of mechanical strength associated with interfacial tension between barium titanate and acrylonitrile–butadiene rubber with different acrylonitrile contents by surface modification

ABSTRACTAcrylonitrile–butadiene rubber (NBR) with different acrylonitrile (ACN) contents was filled with barium titanate (BT) to prepare the polymer dielectrics. The neat NBR, NBR/untreated BT, and NBR/bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (silane coupling agent KH845‐4) modified BT (MBT) composites were prepared. At low ACN content (ACN content 20 wt %), the tensile strength of the NBR/MBT composites increased by 173.6% from 2.69 to 7.36 MPa compared to the neat NBR. The pleasing results were not found in those composites with high ACN content. Both surface modifications of BT and NBR with low ACN content would result in lower interfacial tension between BT and NBR. A strong interfacial adhesion was observed between MBT and NBR with 20 wt % ACN content. The interfacial adhesion had great contribution to the mechanical strength of composites. Moreover, the dielectric properties of composites were also investigated in detail. The addition of BT enhanced the dielectric constant of composites markedly. This study can be applied in manufacturing electronic devices, which are subjected to oily environments for a long time. At the same time, the study can provide some help for researchers to select the polymer matrix and the appropriate surface modification agent of functional filler. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45936.

Investigation of Floor Surface Finishes for Optimal Slip Resistance Performance.

BackgroundIncreasing the slip resistance of floor surfaces would be desirable, but there is a lack of evidence on whether traction properties are linearly correlated with the topographic features of the floor surfaces or what scales of surface roughness are required to effectively control the slipperiness of floors.ObjectiveThis study expands on earlier findings on the effects of floor surface finishes against slip resistance performance and determines the operative ranges of floor surface roughness for optimal slip resistance controls under different risk levels of walking environments.MethodsDynamic friction tests were conducted among three shoes and nine floor specimens under wet and oily environments and compared with a soapy environment.ResultsThe test results showed the significant effects of floor surface roughness on slip resistance performance against all the lubricated environments. Compared with the floor-type effect, the shoe-type effect on slip resistance performance was insignificant against the highly polluted environments. The study outcomes also indicated that the oily environment required rougher surface finishes than the wet and soapy ones in their lower boundary ranges of floor surface roughness.ConclusionThe results of this study with previous findings confirm that floor surface finishes require different levels of surface coarseness for different types of environmental conditions to effectively manage slippery walking environments. Collected data on operative ranges of floor surface roughness seem to be a valuable tool to develop practical design information and standards for floor surface finishes to efficiently prevent pedestrian fall incidents.

Enhanced dielectric constant of acrylonitrile–butadiene rubber/barium titanate composites with mechanical reinforcement by nanosilica

Acrylonitrile–butadiene rubber (NBR), a synthetic rubber having C≡N dipoles, was chosen as a polymer matrix with a higher dielectric constant than other non-polar rubber like silicone rubber or ethylene–propylene–diene monomer. Barium titanate (BaTiO3), as a ferroelectric material, with a high dielectric constant and low dielectric loss was selected as a main filler to further enhance the dielectric constant of NBR. An effective silane coupling agent (KH845-4), selected from five types of silane coupling agents with different characteristic functional groups, was used to modify the surface of BaTiO3 particles to enhance its interfacial adhesion to the matrix. Fourier transform infrared spectroscopy (FTIR) was used to verify the successful modification. The addition of BaTiO3 obviously enhanced the dielectric constants. In particular, an uncommon pattern of dielectric loss has been displayed and analyzed in this paper. Nevertheless, the reinforcing effect of mechanical strength of the NBR/treated BaTiO3 composites is limited. On this basis, the addition of nanosilica (SiO2), replacing part of NBR, improved the mechanical strength. Confirmed by scanning electron microscopy (SEM), the SiO2 and treated BaTiO3 particles were dispersed well in the NBR matrix. The tensile strength was increased from 4.33 to 6.12 MPa when SiO2 accounted for 4%. Moreover, the curing characterizations, crosslinking density, resistivity, and oil resistance were evaluated. This composite material can be used in manufacturing electronic devices, which are subjected to oily environments for a long time.

Kinetics of substrate utilization and bacterial growth of crude oil degraded by Pseudomonas aeruginosa.

Pollution associated with crude oil (CO) extraction degrades the quality of waters, threatens drinking water sources and may ham air quality. The systems biology approach aims at learning the kinetics of substrate utilization and bacterial growth for a biological process for which very limited knowledge is available. This study uses the Pseudomonas aeruginosa to degrade CO and determines the kinetic parameters of substrate utilization and bacterial growth modeled from a completely mixed batch reactor. The ability of Pseudomonas aeruginosa can remove 91 % of the total petroleum hydrocarbons and 83 % of the aromatic compounds from oily environment. The value k of 9.31 g of substrate g−1 of microorganism d−1 could be far higher than the value k obtained for petrochemical wastewater treatment and that for municipal wastewater treatment. The production of new cells of using CO as the sole carbon and energy source can exceed 23 of the existing cells per day. The kinetic parameters are verified to contribute to improving the biological removal of CO from oily environment.

Indirect Clamping Force Measurement Method Using Current Sensor for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission System

This paper introduces an electro-mechanical dual acting pulley continuously variable transmission (EMDAP CVT) system and presents a method of measuring belt-pulley clamping force indirectly using a DC motor current sensor. The EMDAP CVT mainly consists of two movable primary (input) and secondary (output) pulley sheaves connected by metal pushing V-belt. Two DC motor’s actuation systems adjust the CVT ratio. Additionally, the secondary actuation system controls belt-pulley clamping force by adjusting the flatness of the spring discs placed at the back of each secondary pulley sheave to keep the belt tight and prevent belt slip. Ideally, a force sensor is used to measure the belt-pulley clamping force however the use of force sensor inside transmission gearbox is not feasible due to high temperature and oily environment. A viable solution for indirectly measuring the clamping force using current sensor for DC motor is proposed. Since the DC motor actuates the movable pulleys to clamp the belt, the relationship between the DC motor current and belt-pulley clamping force can then be investigated experimentally. The results will give positive impact on precisely controlling belt-pulley clamping force of EMDAP CVT using current sensor which is relatively simpler and less expensive than force sensor.

Determination of Phthalate Plasticisers in Palm Oil Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC)

Contamination of phthalates plasticisers to food has raised concern as some of the phthalates are suspected to be endocrine disruptors. The phthalates have high affinity with oily environment and analysing these chemicals in such matrices is difficult because of the trace amount of the analyte and interference from matrix. An online solid phase extraction (SPE) technique using a large volume (3.5 mL) injection was developed for the analysis of 6 common plasticisers in palm oil. A simple sample preparation involving alumina as a fat retainer and methanol : acetonitrile (1 : 1) as the extraction solvent was performed prior to the usage of online SPE-LC system. This system consists of two columns, C16for the solid phase extraction (SPE) and C18as the analytical column, and a photo diode array detector. The calibration curves were linear from 5 to 1000 μg L−1, with correlation coefficients above 0.99. The instrumental limit of detection was 3 μg L−1and satisfactory recovery was obtained. A screening on a few samples in the retail market revealed the presence of dibutyl phthalate (DBP) and butylbenzylphthalate (BBP) in the palm oil, with concentration less than 1 mg L−1.

The potential of epiphytic hydrocarbon-utilizing bacteria on legume leaves for attenuation of atmospheric hydrocarbon pollutants.

The leaves of two legumes, peas and beans, harbored on their surfaces up to 9×10⁷ cells g⁻¹ of oil-utilizing bacteria. Less numbers, up to 5×10⁵ cells g⁻¹ inhabited leaves of two nonlegume crops, namely tomato and sunflower. Older leaves accommodated more of such bacteria than younger ones. Plants raised in oily environments were colonized by much more oil-utilizing bacteria than those raised in pristine (oil-free) environments. Similar numbers were counted on the same media in which nitrogen salt was deleted, indicating that most phyllospheric bacteria were probably diazotrophic. Most dominant were Microbacterium spp. followed by Rhodococcus spp., Citrobacter freundii, in addition to several other minor species. The pure bacterial isolates could utilize leaf tissue hydrocarbons, and consume considerable proportions of crude oil, phenanthrene (an aromatic hydrocarbon) and n-octadecane (an alkane) in batch cultures. Bacterial consortia on fresh (but not on previously autoclaved) leaves of peas and beans could also consume substantial proportions of the surrounding volatile oil hydrocarbons in closed microcosms. It was concluded that phytoremediation through phyllosphere technology could be useful in remediating atmospheric hydrocarbon pollutants.

Potential of hexadecane-utilizing soil-microorganisms for growth on hexadecanol, hexadecanal and hexadecanoic acid as sole sources of carbon and energy

Bacteria and fungi in pristine and oily desert soil samples were counted on inorganic medium aliquots containing 0.5% hexadecane, hexadecanol, hexadecanal or hexadecanoic acid, as sole sources of carbon and energy. It was found that the carbon and energy source most commonly utilized by soil bacteria was the alkane n-hexadecane, and by soil fungi hexadecanoic acid. Representative microorganisms were isolated and identified. The most predominant bacteria in all soil samples belonged to the genera Micrococcus and Pseudomonas; less dominant bacteria belonged to the group of nocardioforms. The most frequent fungal genera were Aspergillus and Penicillium, while Microsporium and Ulocladium were minor fungi. Irrespective of the substrate on which the microbial strains had initially been isolated, the majority of the isolated microorganisms could grow, albeit to a varying degree, on an inorganic medium containing any of the remaining three substrates as sole carbon and energy sources. Bacterial strains preferred the alkane as a carbon and energy source over any of its oxidation products, while fungal strains preferred to grow mainly on the fatty acids. Quantitative analysis by gas liquid chromatography revealed that the predominant bacterial and fungal isolates had a potential for the attenuation of the alkane and its immediate oxidation products in the medium. In view of the continuous release of hydrocarbon oxidation products by oil-utilizing microorganisms in oily environments, it is interesting that the indigenous microflora contribute to the uptake and utilization of all such intermediate compounds, thus, having a potential for efficient self-cleaning and bioremediation of oily soils.

NONCONTACT TEMPERATURE MONITORING OF A PELLETING PROCESS USING INFRARED THERMOGRAPHY

ABSTRACT Contact methods are commonly used to determine temperature during food and feed manufacturing processes. This may, however, result in incorrect temperature measurements, because many food and feed materials easily agglomerate around the thermowell tip of the sensors, decreasing their time response; also, it is difficult to measure temperature from moving objects using contact methods. This article assesses the use of thermography to measure temperature throughout the manufacture of poultry feed. The experiment showed that precaution should be used when the temperature difference, between the meal at the outlet of the conditioner and pellets at the outlet of the pellet press, is associated with the temperature rise across the die. Precaution should also be used when the temperature of the pellets at the outlet of the pellet press is used as the peak temperature during the process. Temperature measurements through infrared emissions require improved instrument design to operate in a dusty, damp, steamy and oily environment.

Powered, Air-Purifying Particulate Respirator Filter Penetration by a DOP Aerosol

In 1995, new certification requirements for all nonpowered, air-purifying particulate filter respirators were put in place when 42 CFR 84 replaced 30 CFR 11. However, the certification requirements for all other classes of respirators, including powered air-purifying respirators (PAPRs), were transferred to 42 CFR 84 from 30 CFR 11 without major changes. Since the inception of 42 CFR 84, researchers have learned that the efficiency of electrostatic filter media, in contrast with mechanical filter media, can be rapidly degraded by oil aerosols. Further, confusion may exist among respirator users, since electrostatic PAPR filters have the same magenta color assigned to high-efficiency filters for nonpowered particulate respirators that have been tested and certified for use against oil aerosols (i.e., P100 filters). Users may expect that the magenta color of certified PAPR filters indicates suitability for use against oil aerosols. This may not be the case. To illustrate the potential degradation of electrostatic PAPR filters, new filters certified under 42 CFR 84 were tested using a TSI model 8122 Automated Respirator Tester against charged and neutralized DOP aerosols with intermittent loading schedules. The performance of a magenta-colored electrostatic PAPR filter—one for which the manufacturer's user instructions appropriately indicates is not suitable for use in oily environments—was compared with the performance of several mechanical PAPR filters. In tests against both DOP aerosols, the electrostatic PAPR filter showed a significant decrease in performance at DOP loadings exceeding 400 mg, whereas mechanical filters showed no significant change in the performance except at extremely high loadings. The decreased performance of the electrostatic PAPR filter was found to be significantly greater when tested against a neutralized DOP aerosol when compared with a charged DOP aerosol. While laboratory tests show that the filtration efficiency of this electrostatic PAPR filter degrades with exposure to DOP aerosol, the observed laboratory degradation may or may not affect workplace performance, as similar degradation has not been verified in workplace studies. Based on these laboratory results, a proposed method for evaluating high-efficiency PAPR filters is presented. This proposed method would ensure that high-efficiency PAPR filters (≥ 99.97% efficient and magenta in color) meet critical performance criteria when loaded.