| Quasi-Static Uniaxial Tension Characteristics of Plain-Woven Kevlar KM2 Fabric |
DEC 2002 |
42 pages |
| Authors:
Martin N. Raftenberg; Thomas J. Mulkern; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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 | Quasi-static uniaxial tension tests were conducted on 30.8-mm-wide single-ply specimens of plain-woven DuPont Keviar KM2 aramid fabric (style 706). Six specimens were pulled along the warp direction, and six were pulled along the fill direction. The strength was found to range from 2.07 to 2.33 GPa, with a mean of 2.23 GPa in the warp direction and from 2.47 to 2.77 GPa, with a mean of 2.67 GPa in the ... |
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| Kevlar KM2 Yarn and Fabric Strength Under Quasi-Static Tension |
OCT 2002 |
34 pages |
| Authors:
Thomas J. Mulkern; Martin N. Raftenberg; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Kevlar KM2, 600 denier, was Instron tested in quasi-static, uniaxial tension to determine its strength. Specimens included both single yarns and 68- yarn-wide, single-ply strips of plain-woven fabric (Style 706). Never-woven single-yarn speciens were tested with varying degrees of initial twist. Strength of the untwisted, never-woven yarn was 2.66 +/= 0.04 GPa. The twist multiplier was 1.2. Single warp-oriented and fill-oriented yarns were extracted from Style 706 fabric, tested, and ... |
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| Effects of Processing Conditions on Vacuum Assisted Resin Transfer Molding Process (VARTM) |
MAY 2001 |
54 pages |
| Authors:
Elias J. Rigas; Thomas J. Mulkern; Sawn M. Walsh; Steven P. Nguyen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The continued growth of vacuum-based processes has warranted the development of both models and experimental studies designed to capture the unique aspects associated with this manufacturing technique. To that end, this report summarizes an initial set of experiments that characterize both the process and the resulting mechanical properties of components fabricated under a variety of process conditions. Specifically resin flow studies are presented in part to demonstrate the relative influence ... |
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| Material Properties of Bi-Modal Epoxy Networks |
MAR 2001 |
49 pages |
| Authors:
Stephen J. MacKenzie; Thomas J. Mulkern; Nora C. Beck Tan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The necessity for epoxies in new technologies is overwhelming. For these epoxies to perform at their maximum capabilities, both high strength and toughness must be in the list of mechanical properties. This is where bi-modal networks become important. Their combinations of both long- and short-chain cross linkers vary the cross-link density of the epoxy and thus improve the toughness. Here, a study was done to see if these bi-modal networks ... |
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| A Survey of Current High-Performance Carbon Fiber Characterization Methods |
AUG 2000 |
44 pages |
| Authors:
Steven P. Nguyen; Linda L. Ghiorse; Thomas J. Mulkern; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| This report reviews various test techniques published in the literature for evaluating carbon fiber via the single-filament tensile test, the dry bundle test, the resin-impregnated strand test, and the single-fiber fragmentation test (optical microscopy and acoustic emission). Experimental procedures, data analysis, and statistical tensile strength theory are also described. Each technique is followed by a discussion of the advantages and limitations. Furthermore, a materials property ... |
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| Epoxy Functionalized Hyberbranched Polymer/Epoxy Blends |
DEC 1999 |
29 pages |
| Authors:
Thomas J. Mulkern; Donovan Harris; Alan R. Teets; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| In this preliminary study, two novel hyperbranched polymer (HBP)/ epoxy blends were evaluated to determine their efficiency as blend modifiers and tougheners in a brittle epoxy resin. The HBP is miscible in the epoxy and phase separates as cure progresses to form a two-phase system with a dispersed secondary phase of HBP/epoxy compatibilizers in a rigid epoxy matrix. There is no significant increase in the viscosity ... |
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| Polystyrene/Hyperbranched Polyester Blends and Reactive Polystyrene/ Hyperbranched Polyester Blends |
JAN 1999 |
64 pages |
| Authors:
Thomas J. Mulkern; Nora C. Tan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Newly developed hyperbranched polyols (HBP) possess a highly branched three-dimensional structure and a high density of functional end groups relative to conventional linear or branched polymer molecules. Due to their inherent low viscosity and versatile end group chemistry, these materials are attractive as polymer blend modifiers for improved processing as well as improved properties due to reactive compatibilization. In this work, the incorporation of HBPs in ... |
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