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Cure characterization of an unsaturated polyester resin using near-infrared, fluorescence and UV/visible reflection spectroscopies.

机译：使用近红外，荧光和紫外/可见反射光谱学对不饱和聚酯树脂进行固化表征。

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摘要

This dissertation seeks to characterize the cure reaction of an unsaturated polyester resin using near-infrared, fluorescence and UV/Visible reflection spectroscopies. The results will provide a foundation for developing fiber-optic in-situ cure monitoring techniques based on near-infrared, fluorescence, and UV/Visible reflection spectroscopies for an unsaturated polyester resin system.;Near-infrared spectra of the unsaturated polyester resin during cure showed a decrease in absorption at 1629, 2087, 2117, and 2227 nm. Model compounds representing the reactants and products of the cure reaction were characterized, and assignment of peaks in the NIR were made. Conversion of styrene and vinylene, determined from NIR measurements, were compared with values obtained using conventional FTIR measurements. Discrepancies between conversion values determined from NIR and FTIR measurements were attributed to a difference in sample sizes used for measurement. Using a microgel based reaction mechanism, the effects of temperature on the conversion of styrene and vinylene was discussed.;A strong fluorescence emission was found during cure of the unsaturated polyester resin. As the reaction proceeded, the emission intensity at 306 nm increased. Model compound studies confirmed that the unsaturated polyester vinylene component exhibits negligible fluorescence when excited at 250 nm. The fluorescence emission at 306 nm was attributed to a reduced self-quenching effect of styrene monomer. In-situ fluorescence characterization of the cure reaction was also attempted. Fiber-optic fluorescence measurements taken in-situ at 75°C were found to be higher than those taken by fiber-optics at room temperature, indicating a temperature effect on the fluorescence emission. These results may be a consequence of the static quenching behavior of styrene monomer.;UV/Visible reflection spectra of styrene showed a decrease in the % Reflectance at 255 nm with reaction time. This decrease was attributed to an overall reduction in the absorption index as styrene reacts to form polystyrene. Conversion of styrene calculated from UV/Visible reflection and FTIR measurements were in close agreement. A preliminary investigation into the use of UV/Visible reflection spectroscopy to cure monitor a styrene containing unsaturated polyester resin was also performed. A similar decrease in the % Reflectance at 255 nm with cure time was reported for the unsaturated polyester resin.
机译：本文试图利用近红外，荧光和紫外/可见反射光谱技术对不饱和聚酯树脂的固化反应进行表征。研究结果将为开发基于不饱和聚酯树脂体系的近红外，荧光和紫外/可见反射光谱的光纤原位固化监测技术提供基础。固化过程中不饱和聚酯树脂的近红外光谱在1629、2087、2117和2227 nm处的吸收降低。表征代表反应物和固化反应产物的模型化合物，并确定NIR中的峰。将由NIR测量确定的苯乙烯和亚乙烯基的转化率与使用常规FTIR测量获得的值进行比较。由NIR和FTIR测量确定的转换值之间的差异归因于用于测量的样本大小的差异。使用基于微凝胶的反应机理，讨论了温度对苯乙烯和亚乙烯基转化的影响。;在不饱和聚酯树脂固化过程中发现了强烈的荧光发射。随着反应的进行，在306nm处的发射强度增加。模型化合物的研究证实，当在250 nm激发时，不饱和聚酯亚乙烯基组分的荧光可忽略不计。 306 nm处的荧光发射归因于苯乙烯单体的自猝灭作用降低。还尝试了固化反应的原位荧光表征。发现在75°C下原位进行的光纤荧光测量高于在室温下通过光纤进行的测量，这表明温度对荧光发射有影响。这些结果可能是苯乙烯单体静态猝灭行为的结果。苯乙烯的UV /可见光反射光谱显示255 nm处的反射率随反应时间的降低而降低。该降低归因于当苯乙烯反应形成聚苯乙烯时吸收指数的总体降低。由紫外/可见反射和FTIR测量得出的苯乙烯转化率非常接近。还进行了使用紫外/可见反射光谱法固化监控含苯乙烯的不饱和聚酯树脂的初步研究。据报道，不饱和聚酯树脂在255 nm处的％反射率随固化时间的下降类似。

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  • 作者

    Grunden, Bradley Lyn.;

  • 作者单位

    University of Connecticut.;

  • 授予单位 University of Connecticut.;
  • 学科 Chemistry Polymer.;Engineering Materials Science.;Plastics Technology.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 180 p.
  • 总页数 180
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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