X-RAY DIFFRACTOMETRIC MEASUREMENT OF MICROCRYSTALLITE SIZE, UNIT-CELLDIMENSIONS, AND CRYSTALLINITY - APPLICATION TO CELLULOSIC MARINE TEXTILES

Procedures were developed to enable standard x-ray diffractometric equ ipment to be used to study and compare textile fiber crystallographic characteristics. The approach was based on fitting diffractometric dat a to the Gaussian distribution by weighted regression analysis, which also supported an assessment of error propagation. Crystallite dimensi ons were obtained through the Scherrer method using analytically deriv ed spectral line breadths. Percent crystalline component was determine d by summing background-corrected amorphous and crystalline components of the spectra. A diffractometric analysis was made of samples of rar e textiles recovered from a 133-year old shipwreck, as well as modern fabrics submerged for three months at the same deep ocean site. The mi crocrystallite size of the historic textile materials increased, while the percent crystalline component decreased and unit cell dimensions remained constant. The crystallite sizes of modem linen immersed for t hree months with iron, copper, or alone did not increase, while the pe rcent crystalline component decreased and the unit cell dimensions rem ained constant.