Information is given to explain why or how bromine or nitrogen contributes to phosphorus-containing flame retardants. Amide and amine nitrogen generally increase flame resitance, whereas, nitrile nitrogen can detract. Essentially, all of the phosphorus in a flame retardant is accounted for in the char or solid phase and this is also true when amide or amine nitrogen is present. Nitrile nitrogen can cause a significant reduction in percent phosphorus accounted for in the char. The amount of nitrogen accounted for in the char is dependent upon the type of nitrogen and the atomic ratio of N to P in the flame retardant. When large proportions of amide or amine nitrogen are present they also contribute to flame resistance in the gas or vapor phase. Bromine makes its contribution to flame retardants by acting mainly in the vapor phase, and its action appears independent of phosphorus.
The application of x-ray emission techniques to the qualitative and quantitative elemental analysis of chemically and additively modified cotton textiles has been inv estigated. Sample preparation and calibration techniques which appear to be suitable for the analysis of textile materials have been devised. The method has been applied to a variety of samples containing some 20 individual elements. The technique is useful for identifying the elements present in fabrics finished with poorly defined agents. It has been applicable to problems involving the add-on and subsequent loss of fungicidal agents containing such elements as Cd, Zn, Se, Cl, S, and P. Typical results obtained with a number of modified cottons are given.
Electrostatically precipitated respirable dusts from six major U.S. varieties and growing areas were analyzed. From 81-95% by weight, was under 15 micronm diameter. Composition was affected more by growing location than by variety. Dusts contained 16-28% ash, 8-9% moisture, and 62-76% organic matter, including 16-31% protein and 2-12% cellulose. Inorganic composition reflected soil type and minerals. Major elements were silicon, calcium, potassium, phosphorus, magnesium, and aluminum. Infrared spectra of dusts resembled proteins, but water extract spectra did not. Possible implications concerning byssinosis are discussed.
X-Ray fluorescence analysis has been used for the quantitative determination of the light elements P, S, and Cl, which are used in the chemical treatment of cotton and cotton fabrics. Determinations of the amounts of resins used in the chemical modification of cotton cellulose and cotton fabrics have become increasingly important with the extensive use of such treatments. Chemical methods for these determinations are frequently time consuming and often lack the required sensitivity. If the resin treatment contains a metallic or nonmetallic element not found in cellulose (as is frequently found in the use of organometallic compounds or of simple inorganic salts and oxides), the amount of resin can be calculated from a determination of the specific element. This approach, in turn, requires a rapid, sensitive, and accurate method for the determination of the selected element. The wet-chemical methods for these elements are difficult and time consuming. X-Ray fluorescence has fulfilled this need and determination of these and other elements is performed on a routine basis. Matrix problems which may arise due to the nature of the cellulose material are circumvented by the use of standard disks, which are prepared by adding known quantities of the element with a cellulose material such as cotton and pressing it into a disk. The x-ray fluorescence measurements yield calibration curves which are linear in the range from 0.03% to 10% concentration of the element in the cotton.
Atomic absorption spectrophotometry has been used for the rapid determination of various metallic and nonmetallic elements in crude and refined vegetable oils and in animal fats, many present in levels of parts per million. Various types of crude and refined vegetable oils were analyzed for Ca, Cu, Fe, Mg, Mn, P and Zn. This method of analysis has proven to be less time consuming, as accurate and more convenient than other spectroscopic techniques for elemental analyses.
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