Morphological effects of ballistic impact on fabrics of highly drawn polyethylene fibers

✍ Scribed by C. Richard Desper; Samuel H. Cohen; Abram O. King

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 824 KB
• Volume: 47
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1993.070470701

✦ Synopsis

Abstract

Changes in crystalline structure of high‐tenacity ultra‐high‐molecular‐weight polyethylene fabric brought on by ballistic impact from a small projectile were determined by X‐ray diffractometry. A suitable X‐ray diffraction method that averages out the fiber orientation effects in the diffraction pattern was used. The Spectra 1000™ polyethylene fabrics were successfully characterized in terms of both the predominant orthorhombic and the minor monoclinic crystal content. Crystallinity values for the undamaged fabric are consistent from sample to sample and show an average orthorhombic fraction of 0.61 and an average monoclinic fraction of 0.04. Fabric damage by the projectile impact results in either an increase in monoclinic fraction, attributed to recrystallization at temperatures nearing the normal polyethylene melting point, or disappearance of monoclinic material as that temperature is exceeded. The latter predominates where ballistic penetration is complete. However, actual melting need not be involved: Transformation to the hexagonal (“rotator”) phase and the disappearance of the monoclinic phase could have occurred rather than true melting. © 1993 John Wiley & Sons, Inc.