الفهرس 
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Abstract
Sulfonation of nylon-6 fibers by dichlorobenzenesulfonyl chloride (DBSe) and bromobenzenesulfonyl chloride (BRSC) has a great effect on heat, fire and chemical stability of the fibers. The sulfur content, carbon residue, degree of crimp, and solubility in formic acid were determined. The effect of DBSe and BBSe concentrations, reaction temperatures and time of reactions were studied. The modified fibers treated by DBSe and BBSe show that the best results were obtained with reagent concentration of 25%, reaction temperature of 115°e for 4 hours. At these conditions, the modified fibers by OBSe lose its solubility in concentTated mineral acids and aqua regia and did not burn when put in direct flames, glow and chao- without loosing the fiber form. Also no melting occuo-s at up to 1000oe, when tested in DT A which is the maximum temperature available to this instrument, but with tTeating the fibers by BBSe it lose its solubility in fmmic acid and melted at 696.6°e. Also the activation energies of decomposition are 194 kJ/mole and 132.69 kJ/mole for the !Teated fibers by OBse and BBSe respectively compared to 46 kJ/mole for the unmodified fibers. The modified fibers by OBSe and BBse has sulfur content of 4.9% and 4.5%, carbon residue of 26.4% and 19.8%; 97.3% and 90% degree of crimp respectively.
It was found that the increase in DBSe and BBSe concentration and temperature are more effective for increasing the sulfur content in the modified fibers than increasing the reaction time.
The lowering in strength properties of the modified fibers by OBSe and BBSe was observed.
Our modified nylon-6 fibers by DBSe and BBSe have superior improved properties compared to those indicated in patent and literature by other authors.
The use of modified polyamide by 25% DBSe at 115°e for 4 hours as an additive for lubricating base oil shows that the oil has improved oxidation stability. The lubricating base oil containing 0.25wt% of modified polymer has oxidation tcmpcratUie of 425°e compared with 305°e for lubricating base oil without modified polyamide.
The addition of modified polyamide to the lubricating base oil leads to increase of its activation energy of oxidation from 60.64 to 79.16 kJ/mole. This increase of activation energy of oxidation shows the stability of the lubricating base oil against oxidation and the possibility of the use of modified polyamide by OBSe as an additive for lubricating base oil to stabilize it against oxidation.