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首页> 外文期刊>Journal of Applied Polymer Science >UV AND FLUORESCENCE CHARACTERIZATION OF STYRENE AND METHYL METHACRYLATE POLYMERIZATION
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UV AND FLUORESCENCE CHARACTERIZATION OF STYRENE AND METHYL METHACRYLATE POLYMERIZATION

机译：苯乙烯和甲基丙烯酸甲酯聚合的紫外和荧光表征

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Polymerization of styrene and methyl methacrylate (MMA) were studied by UV and fluorescence spectroscopic techniques. Using a sharp decrease in the extinction coefficient at 250 nm and the fluorescence quantum yield at 308 nm of styrene following polymerization, styrene conversion in solution polymerization by UV and fluorescence measurements were found to correlate well with IR results monitoring the disappearance of vinyl groups, at three different temperatures (65, 70, and 75 degrees C). The activation energy of about 6 kcal/mol was obtained. Using the decrease in UV absorbance of MMA during polymerization, solution polymerization of MMA was studied and compared with IR results. Due to the solvent absorbance, the UV method underestimates the conversion to a certain extent. When a small amount of styrene is added in MMA polymerization as a reactive extrinsic comonomer, the conversion of styrene measured by fluorescence is found to be faster than MMA, due to the characteristic reactivity ratios of MMA and styrene. The correlation curve could be used to estimate MMA conversion from styrene fluorescence, providing a method more sensitive than the viscosity-dependent fluorescence probe technique. Bulk polymerization of styrene was studied by bifurcated fiber-optic fluorescence. Due to self-quenching, little fluorescence of styrene is observed up to 75% conversion, but increases sharply from 75 to 85% conversion, followed by a drastic decrease during the last 15% conversion. In comparison to other methods of following vinyl polymerization such as refractive index, density, and gel permeation chromatography, these spectroscopic techniques provide real-time in situ capability as well as better sensitivity, especially in the later stages of polymerization. (C) 1995 John Wiley & Sons, Inc. [References: 24]
机译：通过紫外和荧光光谱技术研究了苯乙烯和甲基丙烯酸甲酯（MMA）的聚合。聚合后，苯乙烯在250 nm处的消光系数急剧下降，在308 nm处的荧光量子产率急剧下降，因此通过UV和荧光测量，溶液聚合中的苯乙烯转化率与IR结果密切相关，IR结果监测了乙烯基的消失。三种不同的温度（65、70和75摄氏度）。获得约6kcal / mol的活化能。利用聚合过程中MMA紫外线吸收率的降低，研究了MMA的溶液聚合并将其与IR结果进行了比较。由于溶剂吸收，UV方法在一定程度上低估了转化率。当在MMA聚合中添加少量苯乙烯作为反应性外源共聚单体时，由于MMA和苯乙烯的特征反应比，发现通过荧光测量的苯乙烯转化率比MMA快。相关曲线可用于估计苯乙烯荧光的MMA转化率，提供了一种比粘度依赖性荧光探针技术更灵敏的方法。通过分叉光纤荧光研究了苯乙烯的本体聚合。由于自猝灭，在达到75％的转化率时几乎观察不到苯乙烯的荧光，但从75％到85％的转化率急剧增加，随后在最后15％的转化率中急剧下降。与随后进行乙烯基聚合的其他方法（例如折光率，密度和凝胶渗透色谱法）相比，这些光谱技术可提供实时的原位检测能力以及更好的灵敏度，尤其是在聚合反应的后期。 （C）1995 John Wiley＆Sons，Inc. [参考：24]

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