超声引发苯乙烯微乳液聚合转化率的紫外光谱法分析

Determination of the Conversion of Styrene with UV Spectroscopy in Microemulsion Polymerization Induced by Ultrasound

研究了苯乙烯微乳液聚合体系中苯乙烯浓度和转化率的测定方法,探讨了紫外光谱法分析测定苯乙烯浓度的影响因素。实验结果表明：以95%乙醇为溶剂和参比液,紫外吸收波长为247nm时,苯乙烯浓度的范围在9.70×10^-6mol·L^-1-6.95×10^-5mol·L^-1内,其吸光度与浓度呈良好的线性关系,其最大摩尔吸光系数ε为1.384×10^4L·mol^-1·cm^-1。微乳液聚合体系中十二烷基硫酸钠、正戊醇的存在对苯乙烯浓度的分析测定没有影响。苯乙烯微乳液聚合体系中的聚苯乙烯可以通过加95%乙醇进行沉淀分离,残余的微量聚苯乙烯对分析结果无影响。将紫外光谱法与化学法和重量法比较,表明紫外光谱法测定苯乙烯的转化率是可行的,该方法操作简便,灵敏度高。

The determination of the conversion of styrene with UV spectroscopy was studied in microemulsion polymerization induced by ultrasound. The effects of SDS, pentrol and polystyrene on the styrene spectra were discussed. The experimental results show that the concentration of styrene in microemulsion polymerization system can be determined quantitatively at the wavelength of 247nm by UV spectroscopy, and the relationship between the styrene concentration and the absorbence is linear in the range of 9.7× 10^-6 mol · L^-1-6. 95 × 10^-5 mol · L^-1 , meanwhile the molar absorptivity is 1. 384 × 10^4 L · mol^-1 · cm^- 1. The SDS and pentrol presented in microemulsion polymerization system have no effects on the determination of the conversion of styrene. Polystyrene, a resultant in the process of microemulsion polymerization, could be removed by adding 95 % alcohol to the microemulsion polymerization system and making polystyrene to be precipitated. Residual polystyrene does not affect the determination of the concentration of styrene. Comparing the results of UV spectroscopy with those of the chemical analysis and gravimetric analysis, the determination of the conversion of styrene by UV spectroscopy is feasible, and the process is simple and easy.