Study On Preparation And Thermostability Of Insoluble Sulfur

This thesis gave a relatively comprehensive review for domestic and foreign research progress in the preparation technologies of insoluble sulfur (IS). Low temperature melting method was taken to produce IS with normal sulfur. Orthogonal experimental design was used to study the effect of the process conditions on polymerization conversion of sulfur. Considering the conversion rate, high temperature stability and extraction efficiency together, the proper polymerization conditions are as follow:reaction temperature 280℃, reaction time 20min, heating rate 4℃/min, deionized water at room temperature as a quenching solvent with the amount of 10 times of the raw material, solidifying temperature 60℃, solidifying time 2h, ethylene glycol as the stabilizer added into the quenching medium (by 0.6 m%), tetralin as solvent extractant, extraction temperature 70℃, extraction time 10min each for twice, the ratio of solvent to product by 7:1. In this case, IS content in polymerization product can reached more than 43% and IS content in product can reach to 96% approximately after purification. Addition of stabilizer in the extraction or oil-treating process, especially in oil-treating process is beneficial to improve thermostability of IS product. The IS thermostability can be further improved if the stabilizers are simultaneously added into extractant and treating oil. IS thermostability at 120℃ can reach to 50.45% after esters stabilizer C (by 2.0 m%) is simultaneously added to extractant and treating oil. Both conversion of normal sulfur into IS and thermostability have reached the leading level in the same processes.