Constructions with Improved

Transcription

1 AD-75S 650 Development of Composite Constructions with Improved Rain Erosion Resistance Hughes Aircraft Co. prepared for Naval Air Systems Command JANUARY 1973 Distributed By: National Technical Information Service U. S. DEPARTMENT OF COMMERCE JK

2 REPORT NO. P73-43 HAC REF. NO. C6212 DEVELOPMENT OF COMPOSITE CONSTRUCTIONS WITH IMPROVED RAIN EROSION RESISTANCE BY BOYCE G. KIMMEL HUGHES AIRCRAFT COMPANY AEROSPACE GROUP IJANUARY 1973! I I FINAL SUMMARY REPORT Prepared Under Naval Air Systems Command Contract No. N C-0257 Materials and Processes Branch Washington, D.C DD C NATIONAL TECHNICAL INFORMATION SERVICE PI Details of illustrations In this document may be better studied on microfiche APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

3 UNCLASSIFIED Security Classification DOCUMENT CONTROL DATA -R & D (Security CiaI silication of title, body of abstract and index:,g.nnotrtion mu,%t he entered when the overall report is classitied) - ORIGINATING ACTIVITY (Corporate author) 2a. REPORT S-CURITY CLASSIFICATION Hughes Aircraft Company Culver City, California Unclassified GROUP 3 REPORT TITLE Development of Composite Constructions with Improved Rain Erosion Rcsistance 4, OESCRIPTIVE NOTES (Type Ci report and inclusive dates) Final Summary Report, I December 1971 to 31 December AUTHOR(S) (First name, middle initial, last fname) Boyce G. Kimmel 6 REPORT DATE 7a. TOTAL NO, OF PAGES Tb. NO OF REFS January CONTRACT OR GRANT NO 98. ORIGINATOR'S REPORT NUMBERIS N C-0257 P73-43 b. PROJECT NO, c. 9b. OTHER REPORT NO(S (Any other numbers that may be assigned this report) d. I ' DISTRIBUTION STATEMENT Approved for public release; distribution unlimited 1I SUPPLEMENTARY NOTES 12, SPONSORING MILITARY ACTIVITY 0; 1tl1s 'IT Naval Air Systems Command 13 ABSTRACT this document may be better Washington, D. C studied on microficho This report describes the continued investigation of composite constructions with improved rain erosion -resistance. The studies included the effect on the rain erosion resistance as determined by whirling arm tests of such variables as matrix, reinforcement, reinforcement configuration, fiber loading, impact angle and fiber angle. Matrices evaluated included rigid epoxies, flexibilized epoxies, polyurethanes, polyphenylene oxide, polybutadiene and polyimide. Reinforcements included ECG glass, SCG glass, Nomex and Dacron. Most of the work involved the evaluation of reinforcements in unidirectionally reinforced, end-oriented composites. However, a limited effort was also expended in evaluating multidimensional fabrics. The test results show that, with respect to rain erosion resistance, polymeric fibers are superior to glass fibers, high fiber loadings are superior to low fiber loadings, one polymeric multidimensional construction to be far superior to several tested. DD I NOV 1473 UNCLASSIFIED Security Classification

4 Best Available Copy

5 UNC LASSIFIED Security Classification 4KEY WORS LINK A LINK 8 LINK C ROLE WT ROLE WT ROLE WT Rain erosion Composites erosion Plastics erosion End-oriented composites Three-dimensional composites UNCLASSIFIED

6 REPORT NO. P73-43 HAC REF. NO. C6212 :1 DEVELOPMENT OF COMPOSITE CONSTRUCTIONS WITH IMPROVED RAIN EROSION RESISTANCE BY BOYCE G. KIMMEL HUGHES AIRCRAFT COMPANY AEROSPACE GROUP JANUARY 1973 FINAL SUMMARY REPORT Prepared Under Naval Air Systems Command Contract No. N C-0257 Materials and Processes Branch Washington, D.C. 203C0 Approved By: L. B. KELLER ' Manager, Materials and Processes Laboratory Equipment Engineering Divisions Culver City, California APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

7 I r FOREWORD The work described in this report was performed by Hughes Aircraft Company, Equipment Engineering Divisions, Culver City, California under -- Contract N C-0257 under the technical management of Mr. Maxwell Stander, Materials and Processes Branch, Code AIR-52032D, Naval Air Systems Command, Washington, D. C This report covers work from 1 December 1971 to 31 December Previous work on this program was performed under Contracts N C and N C-0167 covering the period from 1 April 1970 to 1 November The assistance of Mr. J. R. Shackleton of Ground Systems Group, Hughes Aircraft Company, Fullerton, California in preparing the scanning electron micrographs and Mr. A. A. Castillo in preparing the composite moldings is gratefully acknowledged. 1 II SI i iii

8 I II J CONTENTS - ABSTRACT I SUM M ARY... 3 INTRODUCTION... 5 EXPERIMENTAL... 7 Rain Erosion Testing... 7 Specimen Preparation... 8 Impregnation of Reinforcements... 8 Plasma Etching of Reinforcements... 9 Molding Procedure Machining of Specimens " Determination of Composition and Void Content Rain Erosion Test Results Effect of Matrix Effect of Reinforcement Reinforcement Configuration Effect of Hardener Concentration Effect 1 of Fiber Loading (Nomex-Epon 828/MPDA) Effect of the Fiber Angle and Impact Angle Effect of Glass Finish and Dielectric Filler Electrical Properties AFML Whirling Arm Test Results Radome Fabrication I Prerdn ap n- V

9 I I K I 1 LIST OF ILLUSTRATIONS 1Figure Page 1 Roving Wound on Frame ' 2 Frame Assembly with Impregnated Roving in Place Molding of Unidirectional Composite Composite Bar Cured in Channel Mold ECG Glass Roving - P13N Polyimide, End-oriented (Reinforcement Content volume-percent) ECG Glass Roving - Epon 825/Versamid 140 (65/35), J 7 End-oriented (Reinforcement Content = volume-percent.. 18 ECG Glass Roving - Epon 825/Versamid 140 (55/45), Endoriented (Reinforcement Content = 74.7 volume-percent) Scanning Electron Micrographs of Specimen EP-9A I (ECG-Epon 825/Versamid 140, 55/45, end-oriented) ECG Glass Roving - Epon 825/Versamid 140 (80/20), Endoriented I 10 (Reinforcement Content = volume-percent) ECG Glass Roving - Uralane 5716, End-oriented (Reinforcement Content = 73.7 volume-percent) ECG Glass Yarn, A174 Sizing-FCR 1261-TM303 Polybutadiene, End-oriented (Reinforcement Content= volume-percent) Quartz Roving, 9073 Sizing-FCR 1261-TM303 I Polybutadiene, End-oriented (Reinforcement Content = volume-percent) ECG Glass Roving Polypheitylene Oxide, End- ' oriented (Reinforcement Content = 74.2 volume-percent) ECG Glass Roving Polyphenylene Oxide Crosslinked with Benzenetrisulfonyl Chloride, End-oriented (Reinforcement Content = 79.1 volume-percent) ECG Glass Roving - Epon 828/Hycar/piperidine, End- I oriented (Reinforcement Content = volume-percent) vii

10 LIST OF ILLUSTRATIONS (Continued) Figure 16 Nomex 1200 Denier Yarn - Epon 828/iMPDA, Endoriented (Reinforcement Content ::78. 6 volume -percent) Nomex 1200 Denier Yarn - Epon 828/Versam-id 140, Endoriented (Reinforcement Content =78. 5 volume -percent) Scanning Electron Micrographs of Specimen N-3A (Noniex-Epon 825/\'crsamid 140, end-oriented) Nomex 1200 Denier Yarn - Epon 828 /Mventhane Dian-ine/ NIPDA/BDMNA, End -oriented (Reinforcement Content 79. 5volume -percent) Page 20 Scanning Electron Mlicrographs of Specimen N-6B (Nom-ex- Epon 825/Menthane Diamiine/XlPDA/BDMA. end-oriented) Nomex 1200 Denier Yarn - Epon 828/lycar/piperidine, Endoriented (Reinforcement Content = volume-percent) Scanning Electron Mlicrographs of Specimen N-8B (Nomex- Epon 828/1lycar/piperidine, end-oriented) PRD-49 Type 1, 400 Denier Yarn -Epon 828/MPDA, Endoriented (Reinforcement Content volume -percent) PRD-49 Type 1, 400 Denier Yarn (Plasma -treated) - Epon 825/Versamicl 140, End-oriented (Reinforcement Content volunec-percent) Dacron 1100 Denier Yarn - Epon 828/XMPDA, End-oriented (Reinforcement Content =75. 3 v'olumei-percent) Scanning Electron MNicrographs of Specimen DA-1B (Dacron-Epon 828/MPDA, end-oriented) Dacron Denier Yarn - Epon 828/M\vPDA, End-oriented (Reinforcement Content volume -percent) D)acron I100 Denier Yarn (Plasma -treated) - Epon 828 / NIPDA, End-oriented (Reinforcement Content =73. 6 v'olumepercent) Omniwveave BA (3-D Fabric) (SCC Glass, Type S10 14) - Epon 828/MPDA (Reinforcement Content = volume-percent) Om-niweave AA (3-D Fabric) (Nomex 1200 Denier Yarn) - Epon 828/MPDA (Reinforcement Content = voluime-percent) 'Nonex Fabric Type 3105-Epon 825/Versamid 140 (55/45) (Reinforcement Content =60. 7 volume-percent, not end-oriented) Ominiweave AA (3-D Fabric) (Nomex 1200 Denier Yarn) - Epon 825/Versamid 140 (Reinforcement Content =49. 6 voluimepercent) b4 viii

11 LIST OF ILLUSTRATIONS (Continued) Figure 33 PRD-49 Type III 3-D Orthogonal Construction (Plasma-treated) - Epon 828/MPDA PRD-49 Type III 3-D Orthogonal Fabric - Epon 828/ Menthane Diamine (Reinforcement Content = volume-percent) ECG Glass Roving - Epon 828/MPDA (Fresh, 1.4 times stoichiometric), End-oriented (Reinforcement Content = 75.0 vo!ume-percent) ECG Glass Roving - Epon 828/MPDA (Fresh, Stoichiometric), End-oriented (Reinforcement -' Content = 73,,1 volume-percent) ECG Glass Roving - Epon 828/MPDA (Fresh, 1.6 times Stoichiometri c), End-oriented (Reinforcement Content = volume-percent) F;38 ECG Glass Roving - Epon 828/MPDA (Fresh, 1.2 times Stoichiometric), End-oriented (Reinforcement Content = 75.7 volume-percent) / 39 ECG Glass Roving - Epon 828/MPDA (Old, 1.4 times Page Stoichiometric), End-oriented (Reinforcement Content = 74.8 volume-percent ECG Glass Roving - Epon 828/MPDA (Old, Stoichiometric), End-oriented (Reinforcement Content = volume- ' percent ) ECG Glass Roving - Epon 828/MPDA (Fresh, Stoichiometric), End-oriented (Reinforcement Content = volumepercent) Nomex 1200 Denier Yarn - Epon 828/MPDA, Endoriented (Reinforcement Content = volume-percent) Scanning Electron Micrographs of Specimen N-4A (Nomex Epon 828/MPDA, end-oriented) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented I 45 (Reinforcement Content = 52.4 volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Reinforcement Content = volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Reinforcement Content = volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Reinforcement Content = 41.2 volume-percent)... 8 I ix

12 LIST OF ILLUSTRATIONS (Continued) Figure 48 Nomex 1200 Denier Yarn - Epon 828/IMPDA, End-oriented (Reinforcement Content = volume-percent) Nomex 1200 Denier Yarn (Plasma-treated) - Epon 828/MPDA, End-oriented (Reinforcement Content 41.2 volumepercent) Nomex 1200 Denier Yarn (Plasma-treated) - Epon 828 /MPDA, End-oriented (Reinforcement Content = volumepercent), ECG Glass Roving - Epon 828 /MPDA, End-oriented (Reinforcement Content = volume-percent) ECG Glass Roving - Epon 828/MPDA, End-oriented (Reinforcement Content = volume-percent) ECG Glass Roving - Epon 828/MPDA, End-oriented (Reinforcement Content volume-percent) ECG Glass Roving - Epon 828/MPDA, End-oriented (Reinforcement Content volume-percent) ECG Glass Roving - Epon 828/MPDA, End-oriented (Fiber Angle r 90o) ECG Glass Roving - Epon 828/MPDA, End-oriented (Fiber Angle ) ECG Glass Roving - Epon 828/MPDA, End-oriented (Fiber Angle r ) ECG Glass Roving - Epon 828/NIPDA, End-oriented (Fiber Angle = 30 0 ) Page 59 Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Average Reinforcement Content = 35.3 volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Average Reinforcement Content = 35.3 volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Average Reinforcement Content = 40.6 volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Average Reinforcement Content = 40.6 volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Reinforcement Content = volume-percent) Nomex 1200 Denier Yarn - Epon 828/MPDA, End-oriented (Reinforcement Content = 45.8 volume-percent) X

13 :1. LIST OF ILLUSTRATIONS (Continued) T Figure Page 65 ECG 37 1/0 Glass Yarn, Starch-oil Sizing with Epon 828/MPDA, End-oriented (Reinforcement Content = volume-percent) ECG Glass Roving, 801 Sizing with Epon 828/MPDA, End-oriented (Reinforcement Content = volume- 1 percent) ECG Glass Roving, Epon 828/MPDA, Filled with Titanium Dioxide, End-oriented (Reinforcement Content = 77.3 volume-percent) PRD-49 Type III, Epon 828/Menthane Diamine (AFML Airfoil Specimens) Experimental Radome Structures Fabricated from 1 3-D PRD-49/epoxy Ix I I I I I I xi

14 LIST OF TABLES Table I Page Relative Rain Erosion Resistance of Various Matrices (Unidirectional, End-oriented ECG, SCG or Quartz Roving) Relative Rain Erosion Resistance of Various Matrices (Unidirectional, End-oriented Nomex Yarn) Relative Rain Erosion Resistance of Various Reinforcements (Epon 828/M\4PDA, Unidirectional, End-oriented) Relative Rain Erosion Resistance of Various Reinforcement Configurations (Matrix: Epon 828/MPDA, Except as Noted- Reinforcement SCG Glass, Nomex or PRD-49) Relative Rain Erosion Resistance of Epon 828/MPDA-ECG Glass Roving, End-oriented Composites with Various Hardener Contents (All Specimens Exposed 30 Seconds at 333 Meters/Second) Relative Rain Erosion Resistance of Epon 828/MPDA- Nomex, End-oriented Composites with Various Fiber Loadings (All Specimens Tested at 333 Meters/Second) Effect of Fiber Angle and Impact Angle on Relative Rain Erosion Resistance of Epon 828/MPDA-ECG Glass, Endoriented Composites (All Specimens Tested at 300 Meters/Second) Effect of Fiber Angle and Impact Angle on Relative Rain Erosion Resistance of Epon 828/iMPDA-Nomex, End-oriented Composites (All Specimens Tested at 333 Meters/Second) Effect of Glass Cloth Finish and Dielectric Filler on Rain Erosion Resistance of End-oriented, Fiber-reinforced Composites (ECG-Epon 828/MPDA) Dielectric Properties of Unidirectional, Fiber-reinforced Plastics Composites (Frequency ghz) xii

15 "1" ABSTRACT This report describes the continued investigation of composite constructions with improved rain erosion resistance. The studies included the effect on the rain erosion resistance as determined by whirling arm tests of such variables as matrix, reinforcement, reinforcement configuration, fiber loading,impact angle and fiber angle. Matrices evaluated included rigid epoxies, flexibilized epoxies, polyurethanes, polyphenylene oxide, polybutadiene and polyimide. Reinforcements included ECG glass, SCG glass, Nomex and Dacron. Most of the work involved the evaluation of reinforcements in unidirectionally reinforced, end-oriented composites. However, a limited effort was also expended in evaluating multidimensional fabrics. The test results show that, with respect to rain erosion resistance, polymeric fibers are superior to glass fibers and high fiber loadings are superior to low fiber loadings. One polymeric multidimensional construction was shown to be far superior to several others tested. 11

16 I SUMMARY This technical report covers the third year's effort in the development of fiber-reinforced composites with improved resistance to rain erosion at near-sonic or supersonic speeds. The development of improved composite constructions and their successful application in aircraft radome structures will allow substantial cost savings through less frequent repair and replacement. The program consisted of the determination of the relative rain erosion resistance of a large number of fiber-reinforced plastics composites by whirling arm tests conducted at Dornier Systems, GmbH, West Germany. The variables evaluated included matrix, reinforcement, reinforcement con- T figuration, fiber loading, impact angle and fiber angle. The following types of specimens were evaluated: IT " A standard epoxy matrix combined with various unidirectional reinforcements including ECG glass, SCG glass, Nomex, Dacron and PRD-49. * A standard epoxy matrix combined with various multidimensional constructions. " ECG glass, SCG glass or quartz fibers combined with various matrices. * Nomex fibers combined with various epoxy matrices. " Glass fiber-reinforced, end-oriented epoxy composites at various impact angles and fiber angle with respect to the specimen surface. * Nomex fiber-reinforced, end-oriented epoxy composites at various impact angles and fiber angles. In addition, the dielectric constant and loss tangent at 9.28 gilz were Icalculated from resonant cavity electrical measurements made on several composite systems which showed promising rain erosion resistance. Preceding page blank 3

17 The results of the rain erosion tests showed that rain erosion resistance is substantially increased by the use of polymeric fibers such as Nomex or Dacron, high fiber loadings and flexibilized matrices such as flexibilized epoxies or polyurethanes. End-oriented composites reinforced with Nomex fibers were found to have excellent rain erosion resistance for brittle, rigid or flexibilized matrices. One multidimensional construction woven from Nomex was found to be fairly rain erosion resistant, far more so than a corresponding construction woven from S glass. 4

18 I I j} INTRODUCTION I" Rain erosion tests performed for the U. S. Navy by the University of Cincinnati' have demonstrated the superior rain erosion resistance of endoriented fiber-reinforced plastics composites when compared with the conventional, fabric -reinforced composites. I j j Further study of end-oriented plastic composites at Hughes Aircraft Company under Navy Contracts N C-0315 and N C-0167 has confirmed the superior rain erosion resistance of end-oriented plastics. On the other hand, highly directionally reinforced composites fabricated from three-dimensional fabrics and directional fabrics so as to contain a large fraction of end-oriented fibers were found to be no more rain erosion resistant than conventional, fabric -reinforced composites. Degree of fiber loading was found to have a profound effect on the rain erosion resistance of unidirectionally-reinforced, end-oriented, epoxy-glass composites. Epoxy-glass composites with high fiber loadings (greater than 70 volume-percent) were found to be highly rain erosion resistant, though apparently subject to localized erosion by spallation. 1Lower fiber loadings are permissible for polymeric fibers such as Nomex (polyaromatic nylon) or Dacron (polyethylene terephthalate). End- 1 oriented composites containing these fibers are not subject to spallation as are the end-oriented composites reinforced with glass fibers. Tough, flexibilized matrices were found to be more rain erosion resistant than rigid matrices when reinforced with glass fibers. Nomex fibers, on the other hand, appear to give composites with good rain erosion resistance whether combined with rigid or tough, flexibilized matrices. :Progress Report, Dept. of Mechanical Engineering, University of ICincinnati, "Testing of Rain Erosion Resistance," 19 September

19 Based on the results of the previous work at Hughes, further activities were concentrated on composites containing polymeric fibers, lower fiber loadings consistent with those achievable in radome structures, fiber finishes for polymeric fibers, and the effect of fiber angle and impact angle on Nomexreinforced composites.

20 I E XPER IMENTAL RAIN EROSION TESTING I I Most of the rain erosion testl were run in the whirling arm facility operated by Dornier System GmbH, Friedrichshafen, West Germany. Dornier's apparatus consists essentially of a rotor driven by a powerful electric motor. The rotor is contained inside a chamber which may be partially evacuated as required for high testing speeds. Water drops of the required size and quantity arc injected into the chamber at eight points around the periphery. The specimen holder can be adjusted to allow impact angles ranging from 15 to 90 degrees. The specimens consist of circular discs mm ( inch) in diameter by ram ( inch) maximum thickness. The specimen is secured to a specimen holder at the end of the rotor by means of a retaining ring. During the test, one face of the specimen is subjected to simulated rain erosion under controlled test conditions. All of the specimens evaluated during this reporting period were tested under the following conditions- 3 * Velocity or 333 meters/second I Droplet diameter mm * Impact angle - 30 to 90 degrees. Exposure time- 10 to 120 seconds 0 Rain density x 10-5 (equivalent to a rainfall rate of j7.5 inches per hour) Prior to testing, the weight and thickness of each specimen are I measured and recorded. The responses measured for a given exposure time are weight loss and erosion depth. In addition, the specimens are examined visually, with specimens of particular interest also being examined with the 7

21 r aid of a scanning electron microscope. Repeated weight loss measurements of the same specimen are not made for various exposure times. Instead, one or more sets of specimens machined from the same composite are subjected to different exposure times. Rain erosion tests were also run on one material of interest in the whirling arm facility at AF3ML. The test conditions used were a velocity of 500 mph, and a simulated rainfall rate of one inch/hour with an average raindrop diameter of 1. 8 mm. SPECIMEN PREPARATION Impregnation of Reinforcements The 3-D (three-dimensional) fabrics were pre.-impregnated with the epoxy resin system using a vacuum-pressure impregnation process. Prior to impregnation, a piece of the fabric was encased in a closely fitting shell of polycarbonate film by vacuum forming. After cutting a number of slits in the film to allow resin penetration, the encased fabric was placed in a small container and subjected to vacuum (pressure torr) for one hour to remove residual volatiles. The Epon 828-MPDA mixture, preheated to 140'F, was added under vacuum until the fabric was immersed in resin. The vacuum was released and the pressure was increased to 90 psig and held for two hours. The resin was allowed to gel for 16 hours at 175 F and was cured for two hours at 325 F. After chipping away the excess resin, the polycarbonate parting film was removed. The final composition and void content of the glass reinforced composites were determined by resin burnoff and density measurements made on a small section of the cured composite. The composition of the Nomex 3-D composites was calculated from the known density of the unimpregnated 3-D fabric with the assumption that the packing function of this material is not changed by the impregnation and curing procedure. A procedure was developed to allow the impregnation of rovings or yarns after winding on a series of frames. A specified number of turns of roving is wound on each of several frames as shown in Figure 1. During winding, the portions of the fibers nearest the frame spools are coated with RTV silicone rubber, leaving a 4-inch long uncoated center section. After 8

22 Figure 1. Roving wound on frame. curing the RTV, the fiber loops are removed from the frames and vacuumpressure impregnated with the resin system. In practice, the fiber loops are bent into a U-shape and placed, with the uncoated portion of the fibers downward, in a small beaker. The vacuum-pressure impregnation consists of covering the fiber loops with the resin while under vacuum and then increasing the pressure to psig. Some very viscous resins with short pot lives cannot be heated to lower the viscosity and do not penetrate to the center of the fiber bundles. In this case, the fibers are spread and the resin is applied manually with a small brush to aid in wetting the fibers. This hand application of resin supplements the vacuum-pressure impregnation and may be performed before or after. Plasma Etching of Reinforcements Three polymeric fibers (in the form of roving or 3-D fabric), Nomex, Dacron and PRD-49, were subjected to a low pressure plasma in an attempt to promote adhesion between the fiber and the matrix. The apparatus consists essentially of a small, glass chamber containing a low pressure gas which is continuously subjected to radio frequency by electrodes located outside the 9

23 vacuum chamber. The resulting plasma reacts with the surface layers of the material being treated, usually resulting in improved bondability of typical organic polymers. The device (International Plasma Corporation's "Plasma Machine") is equipped to allow plasma treatment with different gases. The Nomex, Dacron and PRD-49 fibers were etched for 2 minutes with air at a pressure of 2 torr and 15 minutes with helium at a pressure of 15 torr. Each reinforcing material was etched immediately after winding and before impregnation with the epoxy resin. Molding Procedure The loops of impregnated fibers are then secured by wire hooks in a frame assembly as shown in Figure 2. Tension is applied by a spring on the stem of the eye loop on the outside of the frame. The tension is adjusted by the nut on the stem to approximately 40 pounds. After the impregnated roving is centered in the mold cavity, the frame is unclamped from the press. The punch is positioned in the cavity and the press closed to apply pressure to the layup as shown in Figure 3. Usually, shims are placed between the cavity and the punch to allow the molding of a composite of closely controlled thickness and composition. The mold shown in Figure 3 has more rigid sides than a previously used mold, eliminating movement of the fibers between the cavity walls and punch which sometimes occurred with the previous mold. The cavity of the present mold is much deeper, permitting loading of high bulk materials. A typical molded composite bar is shown immediately after being removed from the mold (Figure 4). The center molded portion is nominally 3 inches long with a cross section approximately three-quarters of an inch square. Machining of Specimens The excess material is cut away from the molded composite leaving an oblong bar approximately 3 inches long. After cutting a quarter-inch section from each end and discarding, a half-inch long piece is then cut from the remaining material for determination of density and resin content. 10

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26 Figure 4. Composite bar cured in channel mold. The remaining material is chucked in a lathe and ground to a diameter of inch. Individual specimens are cut off with a diamond saw mounted in a tool post grinder. Finally, one surface of each specimen is surface ground to obtain the final thickness of inch. Profilometer inspection has shown the surface roughness to vary from 11 to 14 microinches. Specimens are machined from composites prepared from the 3-D fabrics with the specimen face parallel to the original surface of the tape. Sufficient material is machined from the surface layer to remove any fabric construction details present at or near the surface resulting in a specimen surface with the maximum degree of end-oriented fibers corresponding to the construction details of the interior of the fabric. Of course the reinforcing fibers in such composites are only partially end-oriented. In addition, the angle interlock fabrics give composites in which the fibers intersect the surface at angles considerably less than 90 degrees. Nevertheless, composites ] prepared from such reinforcements can be considered to be end-oriented. Prior to submission for rain erosion testing, the thickness and weight I of each specimen are measured and recorded. The nominal weight of most of the glass-epoxy specimens is approximately 2 grams prior to testing. Relatively large, unidirectionally reinforced moldings (1-1/8 inches thick by 3 inches by 6 inches) were also made for electrical measurements in a resonant cavity dielectrometer. Moldings were made successfully from Epon 828-MPDA reinforced, respectively, with E glass, Nomex, Dacron and PRD-49 fibers. 13

27 Airfoil specimens were also made from PRD-49 Type III 3-D fabric and epoxy resin for rain erosion tests conducted by AFML in their whirling arm apparatus. The fabrication process consisted of vacuum bagging and curing a wet layup of the fabric and resin system in a female epoxy splash mold. Determination of Composition and Void Content The composition of each molded, unidirectional composite is controlled closely to the desired value by molding to a fixed volume impregnated roving or yarn with a known weight per unit length for the unimpregnated reinforcement. The actual composition of the composites containing siliceous reinforcements is determined by ignition analysis. This composition and the densities of the composite, reinforcement and cured matrix are used to calculate the void content. RAIN EROSION TEST RESULTS The results of the rain erosion tests performed by Dornier are summarized in Tables 1 through 9. The figure references in each table refer to photographs and/or scanning electron micrographs (SEMs) of exposed test specimens. Test results along with photographs and SEMs are included for a large number of test specimens submitted under the preceding contract. Although weight loss data received from Dornier was previously reported, the exposed test specimens were not available for examination until after the period of performance of the preceding contract. The following conclusions have been drawn from the test results and from examination of the exposed test specimens. Effect of Matrix Only the epoxies (rigid or flexibilized) and a polyurethane were found to have fair to good rain erosion resistance when combined with end-oriented glass fibers. Other matrices which had poor rain erosion resistance included a polyimide, a polybutadiene, a polyphenylene oxide, a cross-linked polyphenylene oxide and an epoxy containing a carboxy terminated butadieneacrylonitrile copolymer (B. F. Goodrich's Hycar CBTN) as a toughening agent. 14

28 Several matrices were shown to have good rain erosion resistance when combined with end-oriented Norex fibers. These included, besides the standard Epon 828/MPDA, Epon 825/Versamid 140, Epon 828 /menthane diamnine/mpda/bdma and Epon 828/Hycar/piperidine. The various Nomexreinforced composites varied substantially in the degree to which cracking occurred. The Epon 828/MPDA specimens (Figures 16, 42, 45, 46, 47 and 48) appeared slightly deformed, possibly from the high centrifugal loads imposed during the test. In some cases (e. g., specimen No. N-2A, Figure 16), dimensional changes prevented removal of the specimen from the specimen holder without severely damaging it. Effect of Reinforcement Three polymeric fibers, Dupont's Nomex, Dacron and PRD-49, are compared in the form of end-oriented, fiber-reinforced composites in Table 3. * The weight loss of the Dacron-reinforced composite was comparable to that of the Nomex composite. However, the Dacron specimens (Figure 25) were only slightly cracked near the edges compared with extensive cracking of the Nomex specimen (Figure 16). The PRD-49 specimens were moderately eroded with most of the erosion occurring in the region of a number of fine cracks which covered the specimens prior to rain erosion testing. Reinforcement Configuration The results obtained on Omniweave multidimensional constructions woven from Nomex and S glass showed the Nomex (Figure 30) to be far superior to the S glass (Figure 29) when combined with the standard Epon 828/MPDA matrix. A composite consisting of the Nomex Omniweave combined with a flexibilized epoxy (Figure 32) also had relatively good erosion resistance. A conventional laminate consisting of Nomex fabric combined with a flexibilized epoxy (Figure 31) was deeply eroded after a 30 second exposure. Effect of Hardener Concentration Figures show the results obtained from end-oriented, epoxyglass specimens made from various Epon 828/MPDA formulations (previous, 15

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30 [II I' a. Specimen No. P1-lA, 30 seconds at 333 meters/second b. Specimen No. PI-iB, 30 seconds at 333 meters/second 1...HUGHES2 I.. a 41" I ""T "" I lot, Figure 5. ECG Glass Roving-Pl3N polimide, end-oriented II III (Reinforcement Content = 66.9 volume-percent) 17

31 a. Specimen No. EP-8A, 30 seconds b. Specimen No. EP-8B, 60 seconds at 333 meters/second at 333 meters/second c. Unexposed Control HUGHES Figufe 6.ECG Glass Roving-Epon 825/Versamid 140 (65/35), (Reinforcement Content-77.0 volume-percent) end-oriented UIIJM 18

32 a. Specimen No. EP-9A, 30 seconds b. Specimen No. EP-9B, 60 seconds a333 meters/second at 333 meters/second w1 I I I I1 HUGHES.2 hgg Glass Roving-Epon 825/Versamid 140 (55/45), end-orientued (Reinforcemrent Content = 74.7 volume-percent) 19

33 - ~~DATE S~ilT>:. -'OPERATOU~ Magnification Anl ofve- y j~ 2. 1 ''-10~ 7~ 44 A * ~ ~ 4_ At ;L Lcel PC VC, -,Z~ Lt.r Ob e ' ~ ~ u j.- S e. i j. -441t~~r:je N Ane- cf *! a ti' c- 4 7 I Operating Gor-dit ioris: Detector TPype 6,Set.ings Figure 8 1juti,,.,Acmen EP-9A 1

34 K SE.! DATA K REQWS 2.I DATE R sr.w E - '7 OPEAT 4L. 1Magnification 5c,000 Cn). o:- S,~- t.. Angle_ c f %"ie Det..7'ode Coating, Operating Conditio~ns: Accel. Potent. as kv Condenser Lens Obj. Lens Detectcor TIype Fip_.Awe 8.Scanning electron,licrographs of specimen 1.P-9A (Cnt) (ECO-Epon 825/Versamid 140, 55/45, end-oriented) N!6~ C- D z ~

35 SE. DATA Rg' ".. S,DATE SECI:; -.OPER tll R..AT Magnification /O )( Angle of 74e;: 4 " AIX_ E Iez Det. e Coatin Operating Conditions: Accel. Poen, Condenser Le.is _ Obj. Lens Detector Type Settings Figure 8. Scanning electron Micrographs of specimen EP-9A (cont) (ECG-Epon 82 5/Versaid 140, 55/45, end-oriented)1 j 22

36 .SF' DATA REQU:EST# 72, DATE S spec I-i Fl-Nfj A... OPEAT ~ L Magnification~ - ~~Angle of View..f. O-. 4 1Detec,-tZ~r :ype /0C) ~ *--Angle ~ of 'Yiew 0 1'~r-.'TA ~~ ) ~~~~ Coating Operating Conditions: tji %,* t Accel. Potet. kv Condenser Lens ~~.. ~ ~ - ),. Obj. Lens - ~ J Detector Type ~ 23

37 S E1 D ATA REQUE.ST DATE~ SPECDENOPERIATOR kmagnification Lngl1e ot 7i ew ai Coatir~zAt 12 ccel. SDt.i:gode- 4, ~~Coating Operating Conditions: Accel. Potent. jj v Condenser Lens Obj. Lens Detector Type Settings Figure 8. Scanning electron IMlicrographs of specimen LP-9A (Cont.) (ECO-Epon 825/Versamid 140, 55/45, end-oriented) A,4C7A? 24

38 SEX' DATA RE: UTST" ~ DATE g SEC1 ~ 4 OPEATOR4 9. ~~~Coa Magnification Angle of 'View ig 570O O 2Ob. Tens. iag:'2&::cr. '2 C Angle of Ve (~~~. ~~Obj. C Coating O0perating Conditions: 4 IAccel. Potent. kv Condenser Lens Lens ~Detector ype isettirgs (Cont.) (ECG-Epon 825/Versainid 140, 55/45, en -r ntd 25

39 SE..' DAT A REQUEST i,.5 DATE SPECfl OPERATOR tangie Magnification h909 of V'ie'. Accel.?c-en:. 'N. _ - ocfl Poen. k0 ~~.. ~~ * *Oprain Cond tei Dceec tr ye : Q **Stins ~ Condenser Lens Figur Sannin 8. elecron INah o pcme P9 (cant)~~~~~~~~~~~oj 2/Vrai 4,554,edoietd '. 26 V Lenso

40 .- 4 VV a. Specimen No. EP-llA, 30 seconds b. Specimen No. EP-1IB, 60 seconds at 333 meters/second at 333 meters/second c. Unexposed Control Figure 9. ECG Glass Roving-.Epon 825/Versamid 140 (80/20), end-oriented (Reinforcement Content volume-percent) 27

41 ' y, c. Cntro Uexpoed HUGHES Lu ~~ -C*P% ~ ^$Ca T Fig la re -1 s. ov CG ng-ra an 5 16, en -o ie t - a(r333feters/eon - 3 aonen 33 meersen d 28Uepse oto

42 T- a. Specimen No. PB-IA, 30 seconds b. Specimen No. PB-lB, 30 seconds at 133 meters/second at 333 meters/second 11 c. Unexposed Control Figjire 11.- ECG Glass Yarn, A-174 sizing-fcr 1261-TM 303 Polybutadiene end-oriented (Reinforcement Content = 77.3 volume-percent)

43 Z4! - ~0. a. Specimen No. PB-2A, 30 seconds -it 300 meters/second b.specimen No. PB-.2B, 2.5 seconds - at 300 meters/second c. Unexposed Control.LILL.H UGHES A F'.gure 1,- Quartz Roving, 9073 sizing-fcr k! 303 Polybutadieneo I end-oriented (Reinforcement Content =75.1 volume-percent) 30

44 Aw 1 a Specimen N.P IA JOSeconds b. Sp~ifi n o.p 4 1 s cod at 333 meters/second at 333 meters/second 44 c. UnxosdC$ to 1 HUGHES2 I pi" ECG Glass Roving Polvphenylone Oxide,

45 a. Specimen No. PO-2B, 10 seconds at 333 meters/second b. Unexposed Control 1 HUGHES 2 2: Figure 14. ECG Glass Roving-534-8o1 Polyphenylene Oxide Cross-Lined with Benzenetrisulfonyl Chloride, end-oriented (Reinforcement Content =79.1 volume-ne'.entl

46 Wi '22 Figure 15. L ijyan iuam u MUOWEs 1400CPAr' COMPA'., S ECG Glass Roving-Epon/ 828/Hy car/ Pipe ridine,-pret end-oriented (Reinforcement Content vlm 33

47 - N N - N C) 0 ck tc bb d N 0' 0~ ~ ~ c0 )C )4 L 000t oo N0 C N4 m V 0C IfV c C, <- U -0 r N _ 0oI C6C L.I I N CL L-44

48 a. Specimen No. N-2A, 30 seconds at 333 meters/second b. Specimen No. N-2B, 60 seconds at 333 meters/second c. Unexposed Control I4 16 NeHUGHES 2 Figure 16 Nomex 1200 Denier Yarn-Epon 828/%PDA, end-oriented (Reinforcement Content 78.6 volume-percent) 35

49 a. Specimen No. N-3A, 30 seconds b. Specimen No. N-3B, 60 seconds at 333 meters/second at 333 meters/second c Unexposed Control?i? I?mA& a a a.4jgf acer I ~.w.n'omex 1200 Denier Yarn-Epon 825/Versamid 140, end-oriente~d (Reinforcement Content =78.5 volume-percent) 30

50 DATE S P c.-: z OPERATOR Magnification~Q k ~~Angle oi' View~ 4 r~~~o - L~ i t ~ ~ ~ 4 ~ ~* - n Q t t. '. AV.' "~Condenser Lens U ADeteco.Tp Coatings Scannin Operating Ccogaditiospciens:3 (Noinex-LpConense Lens en-orened 4, Oj. Lns

51 SE' DATA REQUEST /1 7 -; :2- DATE - SPECi-N 11-,/ OPERATOR Magnification_ /A& A, nj Angle of View...!nee!i.. It, Be'" t e 0 1' jangle Det. Mode of Vie Coating A A '- Operating Conditions: Acce!. Potent. " - kv jicondenser Len-s! t Obi. Lens -;4Detector Tlype Settings Figure 18. Scanning electron micrographs of specimen N-3A (Cont.) (Nomex-Epon 825/Versamid 140, end-oriented) 38

52 SE4 DAAA SECI.'E /3A OPERAT:OR yrf~ Magnification y r..,.angle. of View A ' "2C2O Coa.-,.g -.-_ Mccel. Ob2. " n D t v' 0r :.-:N: Angle ofvf-,,. Det. Yode /V Coating _-_,Operating Conditions: Accel. Potent. - kv Condenser Lens - :~~~Obj. Lens.It I Setirs iud Scanning electron micrographs of specimen N-3o c T_ (Con,. (Nomex-Epon 825/Versamid 140, end-oriented) 39

53 se:.: DAA DATE S P 0 11 _,J 3 OPERAT j ~~Magnification Angle of View I Angl.e of 7iew 'b;- 4> ~~~Det. *.ode j!coating Operating Clonditions: ~~ Accel. Potet.2.kv I.Conden~ser L e.s Obj. Lens Detector Tye SettingS A c ~. LL1 u W rogrtpiis of specimen N-3A 40

54 a. N-A, Secimn 3-, No cndsb. a.~~a N-6A,30 Speime No. at 300 meters/secondat30 Specimen No. N-6B, 60 seconds rcon eer/con c. Unexposed Control 1 HUGHES2 Figure 19. Nornex 1200 Denier Yarn-1Epon 828/Menthane Diamine/MIWDA/BDMA, end-oriented (Reinforcement Content =79.5 volume-percent) 41

55 sz:.~date SPECfl=-iN~~ (0PERATOR ~Magnification P9 IAngle Of View 44 Coatix Ob. ons \ '>r Det.!,ode _ CoatgAA.. ~ Operating Condit ions: Accel. Ptn.k ~~.7'j'Condenser Lens Obj. Lens Detector T1ype Settings Figure 20. Scanning electron micrographs ot specimen N-bB (Nomex-Epon 828/menthane dizine /MIPDA/B;DMA, end-oriented) '12

56 SE4 DATA REQUEST #2 2 DATE 27 I. SPEE.ii 13O! MAOR)~. Magnification 5ooi) Angle of 14 ew Ob;. - _.. Anrr'fl e of 7 " 114 ~~~Coating 4 Operating Conditions: en-accel. roenent.) ICondenser IezS Obj. Lens -4 Awb Det'Zector Type 7 Settings.kv ~, I Alec, It) Figure 20. (Cont.) Scanning electron micrographs of specimen N-bB (Nomex-Epon 828/menthane diamine/1npda/bdma, end-oriented) 4

57 R.EQUE~STDAE2 SPECL~iAl SE-1 DATA _40OPERATOR~ A--~% '" 1~'~i~ '~Angle of w Magnification I -, vt %r, Obr ~rs-.'c D. r-~ Figure 20. Scanning electron micrographs of specimen N-6B (Cont.) (Nomex-Epon 828/menthane diamine/mpda/bdma, end-oriented). 44

58 a. Specimen No. N-8A, 30 seconds at 333 meters/second b. Specimen No. N-8B, 60 seconds at 333 meters/second c. Unexposed Control,1 HUGHES 2 Fiure -±. Nomex 1200 Denier Yarn-Epon 828/Hycar/Piperidine, end-oriented (Reinforcement Content = 78.6 volume-percent) 4;

59 S E- D.A_ REQUEST r, 72-.t' DATE SPEC i-en 13 OPE Magnification /00-2 Angle o I Viewz 0 Cozic A Iv, _ CQ... Obl-. e s I "i I: "44 odiios :,Oertig _A."c.l. - o _._...,_.. - N.. 4 '.j - ~ - adetector Typ.- ~t~ilk Dot * :.:ode A.-ete. oeatingc Condenser Lens Detector Type Al,,TC r -6 Figure 22. Scanning electron micrographs of specimen N-8B (Nomex-Epon 828/Hycar/piperidine, end-oriented) 46

60 SE~1 DATE Magnification /00) An-le of View Coazir.Eg AAA,~ ~' ~ ~' V ~2. _ - AnglE, o, j *f N ~~ ~ ~ Dt,:ode Operating Conditions: ~~ ~Condenser Lens 'k.. %Obj. Lens -~~~ Detector yrpe *Figure 22. Scanning electron micrographs of specimen N-8B (cont) (Noniex-Epon 828/Hycar/piperidine, end-oriented) 47

61 SE-1 DAA REQUEST'-' 2. DATE 2'/AIA-IL SPECfl. OR Magnification *44Angle cf' ej Co Oi A A... 6ot-~ "?d"" J i.ljf P SeW AlCoating~ _ Operating Cond.tions: -Con~denser Len Obj. Lens.~ Detct-'or Type Figure 22. Scanning electron micrographs of specimen (Cont.) (Nomex-Epon 828/Hycar/piperidine, end-oriehted) 48

62 SE.D DATA "-;79 r DATE 2? SE13M OPERATOR)/ Magnification -F Angle of View "-. ' 'ti 4, "' Cootnga J t,, ',, Accel.Poet_ k ' I' # Ob. Le-ns 8n Potent.o lt et9 (cunt) ~~ ~ ~ ~ ed-rintd ~ ~ ccl?otent.n82/lyarpierdi Co49e es

63 5S~ DATTA2 REQUEST# 7~5DT?i~ SECflIEN ~T OPEATO~ Magnificatio1.~ '~~ Angle of Vie ~ Coatig rra accel. Poten-;. - 'Ma g 4~et!,:ode - 'C.ei 'otnt.2 *'~~ - ~C'~ ~' - Obj. Les.4 a ~~~ ~ ~ Detector :ypa.. -. ~~~~Settings Figure 22 cnigeeto irorpso pcmnn8. (Nme.Eo 82/va/ieii n-retd (Cont Xs

64 UC) TT 0~ 0 LC) "- N., N N : NN... I" o< C)C)C) ) 1, o,,,.. C -, C " CL 0 0 I-~'U 0 ' - > ' - C000. C.- ~ ) ~ ~ * ~ ~ ' P. CC~) ~ ~ C 0 - ~ ' 0 C u)))) CLCL~-'.0 0.~.~, -.0 '0 ' C7. ~ 'C ) C )C )) ~ C ~z8r C C_ ) ~ C~ c.''.-.-..r'..-."~.n. U)Z~~~~~~.- ~~ LL / 0'., ~.i

65 P Y.I I;I A 1: b. Specimen No. PR-lB,30 seconds a. Specimen No. PR-lA, 30 seconds a 3 eesscn at 333 meters/second c. Unexposed Control HNUGHESI MUGOOCS AIUCOAFT COM&PA;V Fi gu r e 23. ]kprd 49 Type 1, 400 Denier Yarn-Epon 828/MA, end-oriented (Reinforcement Content =65.6 volume-percent) 52

66 0. SPECIMEN NO. PR-2A, 30 SECONDS AT 333 METERS! b. SPECIMEN NO. PR-2B3, 30 SECOND SECONDS AT 333 METERS! SECOND d. SPECIMEN NO. PR-2D, 60 c. SPECIMEN NO. PR-2C, 60 SECONDS AT 333 METERS! SECONDS AT 333 METERS! SECOND SECOND eunexposed CONTROL Figure 24. PRD-49, Type 1, 400 denier yarn (plasia -treated) - Epon 82 5/Versamid 140, end-oriented (reinforcement content =76. 8 volume -percent). 53

67 a. Specimen at 300 meters/second No. DA-IA, 30 seconds b. Specimen No. DA-IB, 60 seconds at 300 meters/second c. Unexposed Control I HUGHES - " 'L v t- Dacron 1100 Denier Yarn-Epon 828/MPDA, end- (Rein forcement Content = 75.3 volume-percent) ;4

68 SE.M DATA SPEC I:.. ; DA-I 7 OPERATORZ [Magnification /0( 4 ' 1 ", 4 * 4"," f'<,, ;'' ' ',. Accl. of,?c- 7iw_ : :.gle T 4 ~~. C e. o 7-" 1,od I ~1 Coatin- : IID Settings " ". Obj.Ln Detecto Typ Stti ng...,, etetor ed,0 V -~"' ~~ Fi.r,. Scnnn 2u el crnmcorpsjfs eie A (Dcrn-Io M end-oriented)_ Se2L. 0 a 28/ DAden-r Ttes A 55 Lens It -e Figur,. ~~~~ icogahsooseimndai ~ Oer-tn ConSanigelcro

69 RFQu--_s- SEJ! D.;TA DATE Z7A-' spie~i A - 13 OPERATOR. Magnification Angle of View OC( Ob. Lens Detector :Pe Sejk_ - _ V ~~~l Magrificaticn ' 9) Angle of Vie,..: ~~~Det. Mode Coating Operating Conditions: 1Accel. 'otent. kv Condenser Lens Ob. Len Figure 26. (cont) Scanning electron micrographs of specimen DA-iB (Dacron-Epon 828/MPDA, end-oriented) 56

70 -SE.! DA%-i' R-.S'- DATE SPECfL-EN A-If OPERATRjj! Magnification (O0L I..5i I.ng, of Viw.. V 04 f r -I i C- nce- _-' D'tc;z":yp 1' " 4 _Coat'ing_ I. -' - I ' 1" perating Conditions:,. '" t_av l;"'acee. Potent. kv ' Obj. Lens 11 - Setting s Figure 2b. (cont) Scanning electron micrographs of specimen DA-CB (Dacron-Epon 828/_PDA, end-oriented)

71 a I'

72 aspecimen NO. DA-3A, 30 b. SPECIMEN NO. DA-3D, 60 SECONDS AT 333 METERS! SECONDS AT 333 METERS! SECOND SECOND c. SPECIMEN NO. DA-31, 120 SECONDS AT 333 METERS! SECO ND Fimure ~.Rac I ron I 10 I' ei er var n (pla-mat- t reat Iedi 1 1) oil '2 NII II )A, Cml -0 1ienit Cd I i'ein tor vincif v k OflCi -:) o)\i7~-ecni

73 C4 Q V 00 0'4 0 X a 0 > > W M Uc (- V C C, 0 x 0.0 0, r -rt 0 cl -- (I r- 0 (4 U - - w- -,I -- - N, " fl)-r Nl ~ N N m'~ C- ell wi N r r r r o CE at 0' 0 ot ccoc 00 c~1 0' ccn NO 'tc'c coo 'fo' NI Nz z" C, C, C, C C,'N 1I' u z- COd 04 tr N 0 H ~ i C4 o 60

74 a. Specimen No. 3D-SA, 10 seconds b. Specimen No. 3D-5B, 30 seconds at 333 meters/second ar- 333 meters/second ' c. Unexposed Control U r.[sa1 w; a,8 AIj. I.ff 4re 29. Omniweave BA (3-D Fabric) (SOC Glass, Type S1014) - Epon 828/MPDA (Reinforcement Content = 42.3 volumepercent) 61

75 Ii a. Specimen No. 3D-6A, 30 seconds b. Specimen No. 3D-6B, 30 seconds at 333 meters/second at 333 meters/second c. Unexposed Control Figure 3U. Umniweav :u% k3-d Ftbric) (Nomex 1200 Denier Yarn)- Lpun 6-b:1PDA RnforcuwuntI ji Content = 53.8 volume- 62

76 a. Specimen No. L-2A, 30 seconds tat 333 meters/second b. Specimen No. 333 L-2B, 30 raeters/second seconds 7. c. Specimen No. L-2C, 30 seconds at 333 meters/second d. Specimen No. L-2D, 30 seconds at 333 meters/second e, Unexposed Control u Nomex Fabric Type 105-Epon 825/Versamid 140, (Reinforcement Content 60.7 r volume-percent, not end-oriented) 63

77 SPECIMEN NO. 3D-7A, 30 SECONDS AT 333 METERS/ b. SPiCIMEN NO, 3D-7D 60 SECOND SECONDSf T 333 METEiS/ SECOND SPECIMEN NO. 3D-7E, 90 SECONDS AT 333 METERS SECOND 14 HUGHES-'., '4 )-1) 1 abric) (N,)."e-%

78 aspecimen NO. 3D-BA, 30 SECONDS AT 333 METERS! SECOND b. SPECIMEN NO. 3D-BC, 60i SECONDS AT 333 METERS! SCN cunexposed CONTROL liur ~I)~~)~'hI vp. [[1 '-1) oriogonal onst rlct ion ipl -Tia-t-va ee - F pon!%i/\ I)I):.

79 aspecimen NO. 3D-9B, 30 SECONDS b.specimen AT 333 NO. METERS/ 3D-9F, 60 SECOND SECONuS AT 333 METERS/ SECOND cspecimen NO. 3D-9G, 120 SECONDS AT 333 METERS/ SECOND d. UNEXPOSED CONTROL Figure 34. PRD-49 Type III 3-D fabric-epon 8.8/i-renthiane diarnine (reinforcement content volum-e -percent). 66

80 u Cd W 0 0) C) ~ C C ) i 0 0 LO4.f. N - ~. j Ir C) NU C, H ; f-4- In on m 1-D ot) Clc VC) N zi L C t) 4. to to67

81 b. Specimen No. UD-12B, 30 seconds a. Spec-imen No. UD-12A, 30 seconds at 333 meters/second at 333 meters/second c. Unexposed Control I HUGHES e CG Glass Roving-Epon 828/,'IDA (Fresh, 1.4 times stoichiometric),i end-oriented (Reinforj'pment Content =75.0 volume-nercent) 68

82 I- a. Specimen No. UD-13A, 30 seconds b. Specimen No. UD-13B, 30 seconds at 333 meters/second at 333 meters/second c. Unexposed Control r HUGHES, ' 11J - ECG Glass Roving-Epon 828/MPDA (Fresh, stoichiometric), end-oriented (Reinforcement Content = 73.1 volume-percent) 69

83 a. Specimen No. UD-14A, 30 seconds b. Specimen No. UD-l4B, 30 seconds at 333 meters/second at 333 meters/second c. Unexposed Control 1 ~HUGHE: Fiue37. I L~f u GMES AIRCRAFT rco#a#anv oi a1 mnt' EGG Glass Roving-Epon 828/IkWDA (Fresh, 1.6 times stoichiometric), end-oriented (Reinforcement Content =75.0 volume-percent) j 70

84 1 4' a. Specimen No. UD-15A, 30 seconds b. Specimen No. UD-15B, 30 seconds at 333 meters/second at 333 meters/second c. Unexposed Control ~ HUGHES 89 ECG Glass Roving-Epon 828/MPDA (Fresh, 1.2 times stoichiometric), end-oriented (Reinforcement Content = 75.7 volume-percent) 71

85 a. S ecimen No. qd-16ab 30 seconds b. at 333 meters/second. Wi c. Unexposed Control 1 HUGHES Figure 39. ECG Glass Roving-Epon 828IMPDA (old, 1.4 times stoichiometric), end-oriented (Reinforcement Content = 74.8 volume-percent) 71- A

86 a. Specimen No. UD-17A, 30 seconds at 333 meters/second -. b. Specimen No. UD-l7B, 30 seconds X 'N c. Unexposed Control U' HU GHES2S F F, Are E.C~EG Glass Roving-Epon 828/MPDA (old, stuichiometric), end-oriented (Reinforcement Content =69.6 volume-percent) 73

87 a. Specimen No. UD-18A, 30 seconds b"-8 at 333 meters/second a 333cimete No secona3seod, t. c. Unexposed Control :HUGHES 2 S4UGMCS AIA F COMPANV?1Mf A Figur 41.EGG lass Rovig-Epon 828/MPDA (Fresh, stoichiometric), end-oriented (Reinforcement Content =7538 volunie-dercent) 74 imaiis1lauat

88 F u 00 ~ - L C N 0 c 00o 000 InIml.3 a -iam.a

89 Q r 1 -~ 0 C)C w t CCL coo coo - ; C;C ;C ; ; C ;C c wr or CC) 07M 0fqC r (1 (4 i4z) l r f ~ q Nc toa C ;f" -c -c o -c c o -o 0 o -Z I'. C z' - A *o - 7- z~c zc z. C t 76*.

90 a. S eie o N4,3 seconds b. Specimen No. N-4B, 60 seconds a 33 mecrs/scondat 333 MUeerS/second c. Unexposed Control Ii~III~kaI#. Nomex 1200 Denier Yarn-Epor, 828/MPIA, end-orlented I II (Rein forcemen t Content =64.,0 volume--pereent)

91 R ZQUJ-_DATE-2,-7 4~ SECLF/ OPERATO ~~ ;Magnification/OY tic., y" Z *~, *~*.%x4 :Uf. WFl 4A;P4P I Det. :-.nd * Coatin& AAA- x Operating Corndtons: Accel. 1otent.j2 Condenser Lens *. ~~~~~Obj. Lens Detector?y p e Settin-s kv Fi1gure 43. SCallfdin; ellclrcu'i itirographs of bpvclin N-4A 76

92 RE~U~s:~2~i ~DATE -Z7 t SECI~ AOPEATOR 4}I/ ~ '%~i ~~T W Magnification An E Ie cof View, ' I ' " I N( 4 'V C~~~~~~~~Ot~j t, e. Y 2-3 4)1 t j~e~r:~ ~4 H---D kngl.e of~ CoatinE t.voperating 'Condit-o~s Accel. Poten. ~kv 14~~~~ Condenser Lens ~~~Obj. Lens I 7 Detector ".yfpe Settings Alti ~ 4 Figure 43. Scanning eltectron iicrugralphs ot 'spuciiinen N-4A (cont) (Nonwx-Epon. 828/W'DA, end-oriented)

93 REQU~7~(~3DATE SECI~NA/-j~OPE2ATOR~ zz. Magnification -~~~ Ang.le of View J~ccc?... C o ; at t_ ~..._... TV, -I> tec)a c: Angle c f 'ew Coating Operating Condition-s: Acel Potent.~ f~~j V Condenser Lens ~Detector a-ype Settings kv I -- Figure 43. (cont) Scanning electron micrographs of specimen N-4A (Nomex-Epon 828/NIPDA, end-oriented) 80A

94 S-rMl DATA V_,q (A O 5'VVP ) OPEATOR Magnif ication Angle of" Views l bk ~~Coatir'. AA Obj. ;=r ng:. f xiw KCoatin, REU YT; j~ DATE 2 t~- AA- Operating Conditions: Accel. Poten-,.,S kv Condenser Lens Obj. Lens Detector 74ype Settings -- y-irt-43,scanning v lectrwi rugruaplks of spicun N-4A

95 a. Specimen No. N-5A, 30 seconds b. Specimen No. N-53, 60 seconds at 333 meters/second at 333 meters/second ~' r HUGHS J4 L-J via end-oc* (enocmn Uexpoed Contol2. oum -eret

96 a. Specimen No. N-7A, 30 seconds at 333 meters/second b. Specimen No. N-7B, 60 seconds at 333 meters/second c. Unexposed Control Nomex 1200 Denier Yarn-Epon 828/POA, end-oriented (Reinforcement Content 80.3 volume-percent)

97 - ti

98 00... SPECIMEN NO.: N-10A, 30 b. SPECIMEN NO. N-101', 60 SECONDS AT 333 METERS/ SECONDS AIT 333 METERS/, SECOND SECOND SPECIMEN NO. N-101, 120 SECONDS AT 333 METERS/ SECOND d. UNEXPOSED CONTROt HUGHIRS.

99

100 aspecimen NO. N-16A, 30 SECONDS AT 333 METERS! 6. SPECIMEN NO. N-16E, 60 SECOND SECONDS AT 333 METERS/ cspecimen NO. N-16H, 120 SECONDS AT 333 METERS/SECOND F igure 49. Notwx 1200 denier yarn (plasmna -rea ted) F pon 828/ 41.2 volume -percent). 87

101 b. SPECIMEN NO. N- 15D, 60 o. SPECIMEN NO. N-15B, 30 SECONDS AT 333 METERS/ SECONDS AT 333 METERS/ SECOND SECOND c. SPECIMEN NO. N-15H, 120 SECONDS AT 333 METERS! SECOND Figure 50. Nomex 1200 denier yarn (plasma -treated) -Epon 828/ MPDA, end-oriented (reinforcement content 76.8 volume-percent). 88

102 1 + : ' Nf' 'r LP ' t O CC <i 0 IIV 0 Z U 'C ~ ~ - ~ o It, r ec -31. ~ C,, 0,c f-4) t. r I rv c 'c < N 1-4) 14 'C -L S 5

103 r b. Specimen No. UD-19B, 30 seconds a, Specimen No. UD-19A, 30 seconds at 300 meters/second(impact angle,900) at 300 meters/second(impact anle, 90 *) w\ c. Unexposed Control (J. UGESC~ m ECG Glass Roving-Epon 828/MPDA, end-oriented (Reinforcement Content volume-percent) 90

104 a. Specimen No. UD-19C, 53 seconds at 300 meters/second(impact angle,60*) b. Specimen No. UD-19D, 53 seconds at 300 ;,-,eters/seconl(inrnact angle.60*, (Rifrcmn Conen 76. voum1e1et 1 r

105 a. Specimen No, UD-19E, 120 seconds at 300 meters/second(imdact angle.45*) b. Specimen No. UD-19F, 120 seconds at 300 meters/second(impact ange. 4 5) I -JI _h HUG IRQA HES 92

106 a. Specimen No. UD-l9G, 480 seconds at 300 meters/second(impact anee300) b. Specimen No. UD-19H, 480 seconds at 300 meters/second(impact anple.30*) I j".f..l61a 65 -A10C.R64ArT (COM PAN. Figure 54. ECG Glass Roving-Epon 828/MPDA, end-oriented (Reinforcement Content = 76.1 volume-percent) 93

107 a. Speacimen No. UD-20A (Reinforcement b. Specimen No. UD-20B (Reinforcement Content volume-percent). I. t~* Content volume-dercent). 30 seconds at 300 meters/second -w ~ 30 seconds at 300 meters/second (impact angle, 90") >I(impact angle, 90*) N.. c. nexose Ctrol 14 r ~2 1 IHUGHES2 ~& Figure 55. ECC Glass Roving-Epon 828/MPDA, end-oriented (fiber angle - (10*) 94

108 '44 b. Specimen No. UD-20D) (Reinforcement a. Spec~imenl No. UD-20C (Reinforcement Content 76.1 volume-percent). Content =76.7 volume-percent). 53 seconds at 300 meters/second 53 seconds at 300 meters/second (impact angle, 600) (impact angle, 600) c. Unexposed Control HUG HES 2 M aimo aii 11 Figure 56. ECG Glass Roving 5on 828/4PDA, end-oriented iiiti H (fiber angle -6 95

109 a.specimen No. UD-20E (Reinforcement b. Specimen No. UD-20F (Reinforcement Content =76.7 volume-percent).cotn 761vlm-ect) 120 seconds at 300 meters/second 120 seconds at 300 meters/second (impact angle, 450) (impact angle, 450) c. Unexposed Control I ~HUGHES~~ T EG HLUre HE ARC*RAl1 COMPA V INYa L CG lass Rovin g-epon 828/MPDA, end-oriented (fiber angle = 45) 96

110 4 a SpCimten a. Secien D-20 (Rinfrceentb. o. No.7 vu e-p(eifrceent Specimen Ndo. UD-20H (ReinforcemeT Content =76.1 volume-percent), M con d t 767vlme-ercent)ond seconds at 300 meters/secor 'I.8 30 meerssecod secndsat (impact angle, 3Q0) ~(impact angle, 3Q0) c. Unexposed Control 4641~% Ik4A 44 :. ' Figure 58. ECG Glass Roving-Epon 828/b!PDA, end-orientdiiiviiilij~i (fiber angle = 3M).u.Iuuiu8 11iui 97

111 2c a) p r if' if' '0 '.0 '. Z z :3 0C (71 ' a, o 0 0 NN M- M- U) '0'. '..D. '.0 '0 '0 '0 ' 0 >C: Z- u -Z~J T U~ T ~ UUU TU) UUU T c.0 U ~~ u - u OT 0 00 OCO a a C ) 0 - u Z-ZIZ Z C** I C ' C' C C~ C C ~. C mco 0. CL -~ mo CLPoLM o 0.a e R.E.P n..c -P. C 0.C.a o1 : SQ coo c ao r_)c c)c Oc)c) Cc c c nc n))c r-)c On C))C c mc)c))c) c - WC~ LO, C C C I-* r( C; C; C; -If' NC C ;O r-i -~-o'~ 0ioa' I...r n-t C")C M< CC) t UX C,) ~ ~ "~~ C~d~ ~ <V~Z~J W M~~~~~~~~~~ ~ ~ ~ ~ C a aa a ii a * a i iii a aa a ii ali a C) zc~ P -C)-rccI-m ~. W MelMMf IlC l n rt, ( "MMc f ca) Od Co in0 O-.vitf c w o ti, 0 ok r cd C C - [-r f Z C C c 0 Oc0 U ci 1 z,ccc t -98Iz c

112 Nt SPECIMEN NO. N-IA, 30 b. SPECIMEN NO''N- 12B, 30 SECONDS AT 333 METERS/ SECONDS AT 3 3 METERS/ SECONI) (FIBER ANGLE AND SECOND tfibep ANGLE AND IMPACT ANGLIE 90") IMPACT ANGLE - 85') vc. I EeIMEN NO. N- 12D, 32 d. SPECIMEN NO. N-12F, 34 m SECONDS AT 333 METERS '/ SECONDS AT 333 METERS/ SECOND (FIBER ANGLE AND SECOND (FIBER ANGLE AND IMPACT ANGLE - 800) IMPACT ANGLE 750) I V7" HUGHES: 6' 7 8- :8 9' 1-1

113 SPECIMEN'NO. N-12H,.38 J. SPECIMEN NO N-lUl- -SECOND$ AT 333 METERS/ SECONDS AT V,.M SECOND (PIBER ANGLE AND SECOND (Ff$BR AN IMPACT ANGLE = Nr) P CT ANGtti- 654)..A SPECIMEI 4.NO. N SECONDS AT 333 METE.%S/ -SECOND (FIBER ANGLE AND IMPACT ANGLE 600) 'FYI --I SHE

114 VA a. I SPECIMEN SECONDS AT NO. 333 N-138, METERS/ 30 b. SPECIMEN'NO. N-13CI 30 SECOND (FIBER ANGLE AND SE ONDS AT -333 METERS/ SECOlt -'(FIBER ANGLE AND 'IMPACTANGLE 9(r) I ) MPACT ANGLE 850) c; SPECIMEN NO. N-131"s j2 d. SPECIMEN NO, N-13Gf 34 -SECONDS AT-333:METERS/ SECONDS AT 333 METERS/ SECOND (FIBER ANGLE AND SECOND (FIBER ANGLE AND IMPACT ANGLE 800) WPACT ANGLE 750) IT. Ṯ T I V :HUGHES: S-7 A 1 2 V I':)%.

115 SPECIMEN NO. N-13J, 38 f. ECONDS AT 333 METERS/ SPECIMEN.NO. N-13K I 44 UCOND (FIBER ANGLE AND N D SECONDS AT 333 " TERS/ IMPACT ANGLE 700) SECOND (FIBER'AN GLE,4ND 'M IMPACT ANGLE,= 6 0 SPECIMEN NO. -13M, 53 SECONDS, AT 333 METERS/ SECOND (FIBER ANGLE AND' IMPACT ANGLE 600) 1-"' HUG"ES

116 SPECIMEN NO. N-14A,,30 b. SPECIMEN NO. N-r4B, 30 SECONDS AT 333 METERS/ SECONDS AT 333 METERS/ SECOND (FIBER ANGLE AND SECOND (FIBER ANGLE-AND IMPACT ANGLE 900) IMPAC-T NGLE 850) '10 Il'o SPECIMEN NO. N-14C, 2 SECONDS AT 333 METERS/ SECOND (FIBER ANGLE AN'D d. 0ECIMEN NO. N- D, 34 IMPACT ANGLE 800) 5tCONDS AT 333 M TERSI SECPND (FIBER AN LE AND IMtACT ANG E HUGHES

117 "All SPECIMEN 38 '0;trao t4ds, AT 3 S/ SECOND (FISE E ER r b. SPECIM E' NO N 14F 44 RNGTLEAN SECOND AT i3i METERS/ AND IMPACT. ANGLE 700) SECOND FIBER ANGLE AND AND IMP CT ANGLE 65*) SPECIMEN NO. N-14G, 53 SECONDS AT 333 METERS/ SECOND (FIBER ANGLE AND AND IMPACT ANGtE 60PI' 1-17 HUGHES

118 E I' Lx 4r) '0 U '0 ol to OL N c ~ 17 0-if I 4)C - > 0 4,, 0 oh o - w 142 -S c co u In c CLC u 010

119 a. Specimen No. UD-21A, 30 seconds at 333 meters/second b. Specimen No. UD-21B, 30 seconds at 333 meters/second c. Unexposed Control I HUGHES 2 Figure 65.ECG 37 1/0 Class Yarn, Starch-Oil Sizing with Epon 828/MPDA III end-oriented (Reinforcement Content = 77.0 vol.ume-dercent) 11Jill 106

120 b. Specimen No. UID-22B, 30 seconds a. Specimen No. UD-22A, 30 seconds at 333 meters/second at 333 meters/secolld c. Unexposed Control HU GHESICRFTCM Figure 66 ECG Glass Roving, 801 Sizing with Epon 828/MPDA, end-oriented (Reiforcmen Conent 7M volume-percent) 107