Andrew J. Zakrajsek, Daniel J. Valco, and Kenneth W. Street, Jr.

Glenn Research Center, Cleveland, Ohio

Effects of Hydrocarbon-Based Grease on

Rapid Prototype Material Used for Grease

Retention Shrouds

NASA/TM—2010-216896

December 2010
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Andrew J. Zakrajsek, Daniel J. Valco, and Kenneth W. Street, Jr.

Glenn Research Center, Cleveland, Ohio

Effects of Hydrocarbon-Based Grease on

Rapid Prototype Material Used for Grease

Retention Shrouds

NASA/TM—2010-216896

December 2010

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
Acknowledgments

The authors wish to acknowledge support from the following individuals. Tracy Cantley, the Rapid Prototype operator who 

manufactured the parts, Richard Mondry for his assistance in obtaining surface profi les, Mike Handschuh, and

Anna Hartman for providing the Model for Test Sheets.

Available from

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Trade names and trademarks are used in this report for identifi cation 

only. Their usage does not constitute an offi cial endorsement, 

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Space Administration.

Level of Review: This material has been technically reviewed by technical management. 

This report is a formal draft or working 

paper, intended to solicit comments and 

ideas from a technical peer group.

This report contains preliminary fi ndings, 

subject to revision as analysis proceeds.
NASA/TM—2010-216896 1 

Effects of Hydrocarbon-Based Grease on Rapid Prototype Material 

Used for Grease Retention Shrouds 

Andrew J. Zakrajsek, Daniel J. Valco, and Kenneth W. Street, Jr. 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Abstract 

Effects of hydrocarbon-based greases on specific rapid prototype (RP) materials used to fabricate 

grease retention shrouds (GRS) were explored in this study. Grease retention shrouds are being 

considered as a way to maintain adequate grease lubrication at the gear mesh in a prototype research 

transmission system. Due to their design and manufacturing flexibility, rapid prototype materials were 

chosen for the grease retention shrouds. In order to gain a better understanding of the short and long term 

effects grease pose on RP materials, research was conducted on the interaction of hydrocarbon-based 

grease with RP materials. The materials used in this study were durable polyamide (nylon), acrylonitrile 

butadiene styrene (ABS), and WaterClear 10120. Testing was conducted using Mobilgrease 28 and 

Syn-Tech 3913G grease (gear coupling grease). These greases were selected due to their regular use with 

mechanical components. 

To investigate the effect that grease has on RP materials, the following methods were used to obtain 

qualitative and quantitative data: Fourier transform infrared spectroscopy (FT-IR), interference 

profilometer measurements, digital camera imaging, physical shape measurement, and visual 

observations. To record the changes in the RP materials due to contact with the grease, data was taken 

before and after the grease application. Results showed that the WaterClear 10120 RP material provided 

the best resistance to grease penetration as compared to nylon and ABS RP materials. The manufacturing 

process, and thus resulting surface conditions of the RP material, played a key role in the grease 

penetration properties and resilience of these materials. 

Introduction 

The grease retention shroud (GRS) is a relatively new concept that is designed to maintain grease 

lubrication at the mesh of two contacting gears. The GRS has two main functions; catching the grease cast 

off during gear rotation, and reapplying the grease to the gear mesh. An illustration of a GRS concept 

developed at Glenn Research Center is seen in Figure 1. In a traditional grease lubricated transmission, as 

a gear rotates, grease is thrown off and deposits around the casing (Ref. 1). As a result, only a thin film is 

left on the gear teeth that must lubricate the teeth through every subsequent mesh cycle. Without 

replenishing grease on the gear tooth, the grease breaks down faster, thus allowing gear tooth surface 

wear to occur at a higher rate. The GRS prevents this by catching the grease on the walls of the shroud. In 

theory, when the buildup is thick enough on the shroud walls, the teeth will encounter the grease buildup 

and capture the additional grease, thereby returning the grease into the gear mesh. This operation not only 

maintains the grease where it is needed, but also acts to recycle the grease as it goes through the 

mesh/rotational release/captures process. 

The GRS concept was first applied to a research gearbox developed for the four-man lunar rover test 

bed vehicle (Chariot) at Johnson Space Center (JSC) and later Glenn Research Center (GRC) (Ref. 2). As 

a result of the design and manufacturing flexibility provided by the rapid prototype (RP) method and the 

non-load bearing nature of the shroud, the shroud for the Chariot gearbox was built using this method. A 

GRS or any part in a mechanical assembly made out of rapid prototyped material has additional benefits. 

The weight of the piece is significantly less than steel, aluminum, or any other type of metal if made using 

RP materials. The RP process is significantly faster for manufacturing custom parts due to the direct 
NASA/TM—2010-216896 2 

interface of the computer modeler with the process equipment. Using RP would be cheaper than 

purchasing a manufactured shroud because of the complexity of the model and the difficulty involved to 

computer numerical control (CNC) machine a grease retention shroud. 

The research gearbox is currently being tested on the Chariot lunar rover test-bed vehicle at JSC. 

Since the RP shrouds were used in this research gearbox and the effects of the grease on the RP material 

used is not well understood, this study was initiated to identify any compatibility issues that may arise in 

this specific application and for future utility. 

Rapid Prototype Manufacturing Process 

To simplify this study only three RP materials where used and two gear greases. Each material was 

tested with the same gear grease in duplicate. The materials manufacturing process is of importance for 

this study. Each material piece was sent to its own RP machine via a modeling program. Each machine 

then took the file and produced each part using a process compatible to the materials composition. As 

seen in the results, the manufacturing process for these RP materials played a large part in how the 

material was affected by the hydrocarbon-based greases. A FT-IR spectrum of all RP materials can be 

seen in Appendix I. 

When the RP material composed of durable polyamide (nylon) (Ref. 3) was made, an initial layer of 

powder is produced. This procedure is a volume process which fills an imaginary cube with layer-bylayer of powder. As the powder layers build, the machine sinters the powder to solidify the part layer-bylayer. Then, a sintering process heats the powder melting it into the desired shape. This can be a 

problematic process if subsequent powder layers are not completely melting and flowing into the prior 

structure, creating voids or crevices. This is observed primarily on the surface of the layers due to the 

powder being too coarse for complete melting. This is a result of the machine recycling some of the 

powder from a previous fabrication session. 

The second RP material made of ABS (Ref. 4) was constructed by melting the starting material into a 

liquid-solid state, which was then, applied starting from the bottom up to build the part. The ABS material 

comes in a thin rope, around an eighth of an inch diameter similar to the material used in lawn trimmers. 

The material build is started at what will become the base of the component, followed by layering thin 

cylindrical materials in the desired final form. When the final form is reached, the material is sintered. 

After the first layer cools the next layer is laid on top and the process continues throughout the build. This 

produces a finish with long ridges running through the material. These ridges or crevices are found 

throughout the material in an equally spaced pattern. 

 
NASA/TM—2010-216896 3 

The final RP material produced from WaterClear 10120 (Ref. 5) was formed from a liquid building 

from the bottom up. The liquid is placed in thin layers on the building piece where a sintering laser heats 

the material to produce the desired shape. This works well because the liquid will fill in any of the 

crevices and voids to allow for a smooth finish. The liquid is clear forming transparent parts. 

Test Procedures 

A RP test sheet, as seen in Figure 2, was divided into individual specimen at the edges to produce 

eight smaller rectangles and then labeled. There were three sheets made for each of the three different RP 

materials. An interference profilometer (Ref. 6) was then used to measure the original profile of the 

surface of the well in each test section of the material to provide a control to which the results could be 

compared. The datum was also set by photographing the specimen before grease application and visually 

inspecting the specimen. 

Single drops of grease, 0.3 cm (1/8 in.) in diameter, were placed in each of the four sections on the 

rectangles and above the Roman numeral in the designed well. The drops of grease were left on the test 

piece for a measured period of time. For the roman numerals I and II, Mobilgrease 28 (Ref. 7) was 

applied, while for numerals III and IV Syn-Tech 3913G grease (Ref. 8) was applied. The samples were 

left undisturbed in an open plastic housing to prevent unwanted contamination until the designated time 

of inspection. Overall, the test lasted 18 days. Specified times and other testing parameters are given in 

Table 1. The letters A to H were written on each test piece before the test representing the eight different 

exposure durations. Each test included taking visual observations and a photograph while the drop of 

grease was still on the RP materials test piece. After the specified time, the piece was mechanically 

cleaned by physically removing the grease. Initially, solvents were proposed to remove the grease, but the 

possible effects of the solvents on the RP materials were unknown at that time. Therefore, the grease was 

removed mechanically to prevent the experiment from being compromised by deleterious effects of the 

solvents. On the test termination day, three different pieces of material were examined at the same time. 

All visual observations and surface profiles were recorded simultaneously. Later it was determined that 

grease removal could be done more effectively with solvents and the surface profilometry was repeated 

after solvent extraction of the grease. 

The test specimens were then imaged using the interference profilometer to measure surface 

roughness. The test procedure for each piece as explained previously, took approximately 45 min to 

complete. This study was conducted under ambient conditions in an air-conditioned lab (16 C). 
NASA/TM—2010-216896 4 

TABLE 1.—GREASE REMOVAL TIME 

FOR EACH SPECIMEN 

Sample Duration, 

hr 

A 19 

B 47 

C 67 

D 90 

E 163 

F 239 

G 331 

H 428 

TABLE 2.—DISPLAYS SOLVENTS TESTED ON RP MATERIAL AND RESULTS 

Solvent Nylon ABS WaterClear 

Hexanes S N N 

DCM N D S 

D- Dissolved N- No Damage S- Minor Swelling 

TABLE 3.—THICKNESS OF SAMPLE MATERIALS BEFORE AND 

AFTER SOLVENT SOAK WITH SONICATION 

 Nylon ABS WaterClear 

 Thickness, 

cm 

Thickness, 

cm 

Thickness, 

cm 

Solvent Before After Before After Before After 

Hexanes 0.638 0.653 0.640 0.640 0.638 0.638 

DCM 0.639 0.639 0.636 NA 0.635 0.640 

TABLE 4.—THICKNESS OF SAMPLE MATERIALS AFTER TIMED EXPOSURE TO GREASE 

 Mobilgrease, 

thickness, 

mm 

Syn-tech 3913G, 

thickness, 

mm 

Day Nylon ABS WaterClear Nylon ABS WaterClear 

0 2.77 2.80 2.49 2.82 3.03 2.50 

7 2.76 2.77 2.47 2.86 3.01 2.48 

42 2.77 2.76 2.48 2.83 3.01 2.49 

When the testing duration and accompanying photographic and surface profilometry was completed, 

specimens were sectioned to obtain clean materials for solvent testing. Small pieces of RP material 

(approximately 612 mm) were soaked and sonicated for 1 min in either a mixture hexanes or methylene 

chloride. The samples were dried and visually inspected for damage. A virgin sample and the soaked 

samples were submitted for attenuated total reflectance Fourier transform infrared, FT-IR, spectroscopic 

analysis. The FT-IR was equipped with a microscope using an MCT detector and an attenuated total 

reflectance objective with a zinc selenide crystal. 

The RP materials were examined for damage from common solvents employed in grease removal. 

Virgin RP material specimens were measured for thickness and then soaked in analytical grade solvents, 

hexanes (contains mixed isomers) and methylene chloride (DCM), for 1 min. in an ultrasonic bath. 

Afterwards the samples were removed and dried. They were then visually inspected, their thickness 

remeasured and subjected to FT-IR for chemical characterization. Visual inspection data appears in 

Table 2 and swelling data in Table 3. 

Independent grease-swelling experiments were conducted with coupons approximately 10 by 10 by 

3 mm. A spot of grease approximately 6 mm in diameter was placed on duplicate coupons and allowed to 

stand for 7 days. Afterwards the grease was physically removed and the coupon thickness remeasured. 

Grease was reapplied and allowed to remain an additional 35 days. The sample was again mechanically 

cleaned by wiping and the thickness was measured and averaged for duplicates. Data for this experiment 

appears in Table 4. 
NASA/TM—2010-216896 5 

Results and Discussion 

From the solvent exposure studies, Tables 2 and 3, it is necessary to carefully test materials and 

procedures when using RP materials. Some RP materials like the ABS are soluble in solvents like DCM 

and others appear to swell slightly, like the WaterClear in DCM and nylon in hexanes. The FT-IR 

spectrum of the DCM soaked ABS material indicated some structural damage existed, although no 

damage was indicated post-extraction for any other material/solvent combination. FT-IR spectroscopy 

was also used on the solvent-cleaned RP material to determine whether the grease had chemically 

damaged the material. Small spectral changes indicated that there was no damage to the RP materials and 

that the solvent effectively cleaned grease from the porous RP materials. 

The RP materials underwent 18 days of grease exposure for spreading and surface texture, Table 1, 

and 42 days of exposure for swelling, Table 4. Discoloration of nylon and ABS RP materials occurred 

during exposure, indicating a change in the RP material. Discoloration of the nylon and ABS RP 

materials increased over time, while the WaterClear material showed no color change. The nylon saw the 

most significant absorption/discoloration after wiping, to the point where by the end of testing, the 

rectangular testing area was almost completely filled with a tainted hue of the grease’s color. Since this 

test examined the behavior of a single drop of grease, it can be imagined that with a gear rotating and 

subsequent loss of larger volumes of grease over a long period of time this material could eventually 

allow the oil from the grease to penetrate the shroud and begin to leak. The ABS also absorbed a 

significant amount of the oil from the grease, based on the residual discoloration after mechanical 

cleaning. 

The Mobilgrease 28 was spread/absorbed more significantly by the RP materials than the Syn-Tech 

3913G grease. Therefore, unless one of these two greases is being used, additional testing should be 

performed to see how different greases will penetrate and/or spread over the RP materials. RP materials 

may promote the separation of greases. Observations of absorption behavior, as indicated by material 

discoloration after cleaning, can be seen more clearly in Figures 3 to 5, which show the first day versus 

the final day of testing. Measurements of the grease spread diameter versus exposure times are plotted in 

Figure 6. 

To determine the microstructure of the surface, a Veeco interference profilometer was used to record 

the surface profile. Differences between scans before grease application and after test completion are 

shown in Figures 7 to 12 and in tabulated Surface Roughness, Ra, data in Appendix II. In Figures 7 to 12 

the grease was mechanically removed by wiping and using an appropriate solvent for the RP material. 

Figures 7 to 12 are all from the 428 hr tests, with the coupling grease. 

In Figures 7 and 8 the nylon appears to have underwent a major change. However, the roughness only 

changes from 10.1 to 10.6 μm which is not a large surface change. The two scales for the nylon, before 

and after grease application, are 105 and 71.8 μm, respectively. 

In Figures 9 and 10, the ABS images from the interference profilometer are drastically different than 

what was observed with nylon. An error in obtaining accurate Ra values may be attributed to the “ridge 

pattern”. This surface profile is attributed to the manufacturing of the material and how it is built from 

strands of cord producing a pattern of long, parallel alternating ridges and troughs across the surface of 

the material, allowing for grease entrapment and build-up. No evidence of material degradation by grease 

was evident from the surface profiles or Ra values. The ABS surface profiles for the virgin material and 

the grease-exposed RP material are 78.1 and 135 μm, respectively. 

The WaterClear 10120 images from the interference profilometer seen in Figures 11 and 12 appear to 

be very similar. This can be attributed to the smooth surface finish of the WaterClear 10120 RP material. 

The WaterClear 10120 may perform differently from the two other RP materials due to the low relief 

allowing for closer tolerances between the GRS and gears. In addition, it does resist absorption of the 

grease better than the ABS or nylon RP materials. These attributes would contribute to the use of less 

grease in the gearing application. The WaterClear 10120 virgin material and the greased material had a 

scale of 6.75 and 4.32 μm, respectively, which is considered a non-significant change. 

 
NASA/TM—2010-216896 6 
NASA/TM—2010-216896 7 

Surface structure may be important in some applications. Another consideration is surface resistance 

to grease absorption, since clearances in GRS applications may be small to limit the quantity of grease 

employed during testing. Figures 7 to 12 show strikingly different surface finishes for the different RP 

materials. The nylon material has high relief with higher Ra values whereas the WaterClear shows very 

low relief and low Ra values. The ABS material showed parallel ridges with a large peak to valley depth 

formed during manufacture. The data in Appendix II may better demonstrate the ridge pattern than the 

actual roughness of the surface. In Figure 8, the nylon shows similar relief which is supported by the 

average roughness values before and after testing for both greases, suggesting that the grease does not 

react with this RP material. Nylon possesses an uneven topography which allows grease to seep into the 

material crevices causing the grease to stick to the material. Since this material saw the most noticeable 

change, additional images are included in Appendix III. 
NASA/TM—2010-216896 8 
NASA/TM—2010-216896 9 
NASA/TM—2010-216896 10 
NASA/TM—2010-216896 11 
NASA/TM—2010-216896 12 
NASA/TM—2010-216896 13 
NASA/TM—2010-216896 14 

Perfluoroether-Based Grease Experiments 

Experiments were conducted with a new form of rapid prototyped material, Acurra_60 Plastic by 3D 

systems (Ref. 9), and perfluoroether based grease (Ref. 2). This RP material is quite similar to WaterClear 

as indicated in the FT-IR spectra for each of these materials (Fig. 13). A threefold test with gears running 

at 150 rpm and a pressure of 250 psi were run for half a million cycles. No damage to the RP material 

properties were visually observed. At high loads and low speeds, using RP material as shrouding and 

perfluoropolyether-based grease may be acceptable for this application. 

Conclusions 

Effects of hydrocarbon-based greases on specific rapid prototype (RP) materials were explored in this 

study. The rapid prototype method was used to develop grease retention shrouds for a research gear 

transmission. The RP method was used to produce the shrouds due to the flexibility of the manufacturing 

process and the low weight of RP materials. Despite these favorable attributes, using RP materials in a 

fully-operational gearbox may be problematic. The three materials tested have different properties and 

processes for manufacturing that directly affect their ability to resist hydrocarbon grease penetration and 

possible degradation of the RP material itself. The WaterClear 10120 RP material provided the best 

resistance to grease penetration as compared with the nylon and ABS materials. From the test results, the 

WaterClear 10120 RP material appears to be the optimum material for constructing a GRS because 

almost no absorption of the grease occurred, during either the spreading or swelling experiments, and no 

noticeable damage to the surface was seen. This material also possesses lower relief (i.e., lower surface 

roughness) in the final product, allowing closer tolerance in manufacturing. The manufacturing process 

and thus the resulting surface conditions of the RP material play a key role in the grease penetration 

properties and resilience of these materials. In addition, testing the potential harm from using 

hydrocarbon-based grease and cleaning procedures on RP material were assessed. Finally, preliminary 

testing with Accura_60, a material very similar to WaterClear, using a perfluoropolyether-based grease 

showed no signs of wear or degradation throughout the 500,000 cycles of testing. 
NASA/TM—2010-216896 15 

Suggested Future Testing 

Further testing is needed to fully understand the long-term effects of hydrocarbon grease on rapid 

prototyped materials. The effect of operational temperatures, grease grade, and gear clearances on 

material integrity and tensile properties should be explored. Other RP materials and grease combinations 

should be investigated. One new RP material that should be examined is DuraForm PP 100 Plastic, a 

tough material, similar to the WaterClear. Because the grease retention shroud concept could be 

advantageous in maintaining critical grease lubrication in space mechanism applications, space-qualified 

greases should also be investigated further. 
 
NASA/TM—2010-216896 17 

Appendix A 

NASA/TM—2010-216896 19 

Appendix B.—Roughness Values 

I and II are Mobilgrease and III and IV are Syn-Tech grease 

Ra (micrometers) for Nylon material 

Time, 

hr 

Before grease application After grease application 

 I II III IV I II III IV 

19 13.0 13.4 13.9 13.1 11.5 14.8 11.1 11.0 

47 16.5 10.9 13.1 12.3 13.9 13.4 9.9 12.2 

67 10.1 10.4 10.1 10.1 11.4 12.4 9.5 8.1 

90 11.2 13.8 13.8 10.5 10.1 8.6 10.1 8.2 

163 12.5 13.3 13.8 10.5 11.8 12.8 8.8 8.7 

239 11.1 12.4 12.1 8.7 11.1 9.8 10.1 11.3 

331 14.0 10.9 11.5 11.2 10.3 8.0 10.1 8.0 

428 11.9 10.8 10.1 11.0 11.2 12.1 10.61 11.2 

Ra (micrometers) for ABS material 

Time, 

hr 

Before grease application After grease application 

 I II III IV I II III IV 

19 3.7 18.6 18.1 19.4 7.5 16.5 11.5 18.0 

47 18.9 18.9 19.4 21.3 22.8 13.8 19.1 13.9 

67 10.7 13.2 16.4 18.7 6.9 14.2 17.0 10.3 

90 13.0 19.1 18.1 18.6 9.7 21.5 8.9 10.0 

163 14.7 15.4 15.2 16.3 7.9 10.3 10.0 16.2 

239 14.5 15.6 21.0 23.5 13.5 16.3 10.1 12.2 

331 10.9 20.6 14.5 20.2 5.9 15.4 15.9 8.6 

428 14.8 14.6 12.58 9.8 12.2 13.6 16.94 10.8 

Ra (nanometers) for WaterClear 10120 material 

Time, 

hr 

Before grease application After grease application 

 I II III IV I II III IV 

19 516 261 149 196 292 494 449 212 

47 160 118 107 129 131 134 183 310 

67 253 170 143 222 392 350 289 459 

90 137 90 144 98 192 226 241 178 

163 318 233 190 119 157 218 295 547 

239 238 99 142 234 199 121 529 345 

331 169 188 183 111 985 306 217 226 

428 130 87 185 148.3 245 212 231 114.15 

NASA/TM—2010-216896 21 

Appendix III (A).—Surface Profiles of RP Material Nylon With no Grease 

NASA/TM—2010-216896 23 

Appendix III (B).—Surface Profiles of RP Material Nylon With Grease 
NASA/TM—2010-216896 24 

References 

1. Coy, John J., Townsend, Denis P., Zaretsky, Erwin V., “Gearing,” NASA Reference Publication 

1152-AVSCOM Technical Report 84-C-15, 1985. 

2. R. Handshuh, A. Zakrajsek, High Pressure Angle Gears: Preliminary Testing Results, 

NASA/TM—2010-216251, March 2010. 

3. “Products | Materials | Duraform EX,” 3D Systems | Rapid Prototyping, Advance Digital 

Manufacturing, 3-D Modeling, 3-D CAD. July 2010 

<http://www.3dsystems.com/products/materials/sls/duraformPA.asp>. 

4. “FDM Material Properties,” ABS. Stratasys. July 2010 

<http://www.vistatek.com/pdfs/FDM_ABS.pdf>. 

5. “WaterClear 10120,” DSM Somos WaterClear 10120. July 2010 

<http://www.dsm.com/en_US/downloads/dsms/datasheets/s10120product_data_sheet.pdf>. 

6. “Veeco - Optical Profilers,” Veeco - Solutions for a nanoscale world. July 2010 

<http://www.veeco.com/optical-profiler-systems/index.aspx?gclid=CNWdiL3nu 

KICFQoNDQodAmly5Q>. 

7. “Mobilgrease 28,” MOBIL. July 2010 <http://www.mobil.com/CanadaEnglish/Lubes/PDS/IOCAENGRSMOMobilgrease_28.asp>. 

8. “Greases Designed Exclusively for Shaft Couplings,” KOP-FLEX. July 2010 <http://www.emersonept.com/catalogs/EPT/grease.pdf>. 

9. “3D Systems." Accura 60 Plastic,” June 2010 < http://www.3dsystems.com/products 

/datafiles/datasheets/SLA/DS_Accura_60_US.pdf> 
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Effects of Hydrocarbon-Based Grease on Rapid Prototype Material Used for Grease 

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13. SUPPLEMENTARY NOTES

14. ABSTRACT

Effects of hydrocarbon-based greases on specific rapid prototype (RP) materials used to fabricate grease retention shrouds (GRS) were 

explored in this study. Grease retention shrouds are being considered as a way to maintain adequate grease lubrication at the gear mesh in a 

prototype research transmission system. Due to their design and manufacturing flexibility, rapid prototype materials were chosen for the 

grease retention shrouds. In order to gain a better understanding of the short and long term effects grease pose on RP materials, research was 

conducted on the interaction of hydrocarbon-based grease with RP materials. The materials used in this study were durable polyamide 

(nylon), acrylonitrile butadiene styrene (ABS), and WaterClear 10120. Testing was conducted using Mobilgrease 28 and Syn-Tech 3913G 

grease (gear coupling grease). These greases were selected due to their regular use with mechanical components. To investigate the effect 

that grease has on RP materials, the following methods were used to obtain qualitative and quantitative data: Fourier transform infrared 

spectroscopy (FT-IR), interference profilometer measurements, digital camera imaging, physical shape measurement, and visual 

observations. To record the changes in the RP materials due to contact with the grease, data was taken before and after the grease 

application. Results showed that the WaterClear 10120 RP material provided the best resistance to grease penetration as compared to nylon 

and ABS RP materials. The manufacturing process, and thus resulting surface conditions of the RP material, played a key role in the grease 

penetration properties and resilience of these materials.

15. SUBJECT TERMS

Shrouds; Grease; Chemical analysis 

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STI Help Desk (email:help@sti.nasa.gov) 

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