Accession Number:

ADA235527

Title:

X-Ray Diffraction Studies of Disorder in Allied Spectra-1000 Polyethylene Fibers

Descriptive Note:

Corporate Author:

ARMY LAB COMMAND WATERTOWN MA MATERIAL TECHNOLOGY LAB

Personal Author(s):

• Desper, C. R.

Report Date:

1991-04-01

Pagination or Media Count:

10.0

Abstract:

A recent paper by Busing on the X-Ray diffraction study of polyethylene fibers Busing, Macromolecules, 1990, 23, 4608-4610 has been reviewed and condensed. Busing describes a new and improved method for measuring and analyzing the crystal structure and pertinent morphological parameters of polyethylene in fiber form. More than a determination of structure in a particular fiber, the paper is a pointer to how crystallography may be best accomplished in semi-crystalline polymers in the future. The paper outlines the application of FIBLS, the full-pattern least-squares fiber-diffraction program. The results of the analysis include crystallinity, orientation function, paracrystalline disorder parameters, unit cell dimension parameters, atomic positions, bond distances, and bond angles. The most complete analysis using the difference Fourier method reveals, for the first time, three additional sites for carbon atoms in the unit cell structure, partially occupied by disordered segments of the chain bypassing their usual route in the unit cell to alternative sites. The importance of the method goes beyond polyethylene, or even beyond polymers of interest for fibers applications.

Descriptors:

• *POLYETHYLENE
• *FIBERS
• CRYSTAL STRUCTURE
• SIZES(DIMENSIONS)
• PARAMETERS
• CELLS
• POLYMERS
• MORPHOLOGY
• X RAY DIFFRACTION
• ORIENTATION(DIRECTION)
• ORDER DISORDER TRANSFORMATIONS
• CRYSTALLIZATION
• ATOMS
• CARBON
• MACROMOLECULES
• BONDING
• DETERMINATION
• DIFFRACTION ANALYSIS
• FOURIER ANALYSIS
• CRYSTALLOGRAPHY
• CELL STRUCTURE
• SYNTHETIC FIBERS
• FUNCTIONS
• ANGLES

Subject Categories:

• Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE