Polarization colors of nitrocellulose

Abstract

SynopsisThe polarization colors of nitrocellulose (NC) fibers show an orderly progression from graywhite at 11.0% nitrogen (N) through first-order whites, yellows, and reds to second-order blue at 12.6% N. At higher levels of nitration, the polarization colors revert back to first orders with fibers containing 13.1% N showing gray changing to intense white at 13.5% N. The length-positive and length-negative character of NC fibers also changes with the degree of nitration. Fibers nitrated to about 12.4% N are optically neutral and become increasingly positive with a decrease in the level of nitration and increasingly negative as the level of nitration increases. This optical property and the polarization colors of NC provide much information about the level and range of nitration of NC fibers.

Experimental Study on the Fire Properties of Nitrocellulose with Different Structures

“…Previous work on NC mainly focused on heat of combustion [ 3 ], spontaneous ignition [ 4 , 5 ], morphological behavior [ 6 , 7 , 8 , 9 , 10 ] and thermal decomposition [ 1 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Sovizi et al [ 20 ] investigated the thermal stability of micron- and nano-sized NC by simultaneous thermogravimetry-differential thermal analysis (TG/DTA) techniques.…”

System and Method for Simultaneous Measurement of Nitrogen Content and Uniformity of Nitration of Nitrocellulose

“…Figure 2 shows the sequence structure of cellulose and the mechanism for polarizing microanalysis of the nitration. In 1976, Kohlbeck [52,53] used a suitable immersion liquid to determine the mathematical relationship between the nitrogen content of NC fibres and the polarizing colour. The nitrogen content of NC showed an optically neutral point at 12.3%, while it did not produce a polarizing colour.…”

“…However, this method is tedious, timeconsuming, difficult to operate, and can be easily affected by human factors. Lewis [51] and Kohlbeck [52][53] developed a polarizing microscope for the determination of nitrogen distribution, but this method failed to be of practical Copyright © 2018 Institute of Industrial Organic Chemistry, Poland use due to the lack of manoeuvrability and stability.…”