出版社:Defence Scientific Information & Documentation Centre
摘要:Polystyrene has been nitrated in mixtures of anhydrous nitric and sulphuric acid (70 : 30 and 80 : 20 by volume). Degree of substitution of nitro group per benzene ring varies from 1 to 2 depending on the time, temperature and composition of the nitrating media. Effect of polar and non polar solvents on nitration has been studied by nitrating the polymer in (i) fuming nitric acid and (ii)mixture of nitric and sulphuric acid in presence of dimethyl formamide (DMF) and carbon tetrachloride (CCI/Sub4). MF increase the rate of nitration in fuming nitric acid whereas the rate of nitration is lowered in the presence of DMF in the nitrating mixtures. In the case of CCI/Sub4, however, the effect is just the opposite to that observed in DMF. The results have been explained from the mechanism of the formation of 'nitroniumion,NO/Sub2+ in various nitrating media. Degradation of the polymer has been found to be comparatively less in the presence of the organic solvents used in the study.