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首页> 外文学位 >Characterization of novel polymers by time-of-flight secondary ion mass spectrometry, matrix-assisted laser desorption mass spectrometry, and x-ray photoelectron spectroscopy.
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Characterization of novel polymers by time-of-flight secondary ion mass spectrometry, matrix-assisted laser desorption mass spectrometry, and x-ray photoelectron spectroscopy.

机译：通过飞行时间二次离子质谱，基质辅助激光解吸质谱和X射线光电子能谱表征新型聚合物。

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摘要

Novel polymeric materials are characterized by time-of-flight secondary ion mass spectrometry (TOF-SIMS), matrix-assisted laser desorption mass spectrometry (MALDI-MS), and x-ray photoelectron spectroscopy (XPS). In addition to giving insight into the polymerization processes, the results provide the basis for comparing, evaluating, developing the capabilities of the named analytical techniques.; With TOF-SIMS, characteristic fragment signals in the low mass region ({dollar}<{dollar}500 Da) and intact oligomers in the high mass region (500-10,000 Da) are identified and evaluated. {dollar}rm Msb{lcub}n{rcub}{dollar} values are calculated using intact oligomers. Fragment signals (endgroup/polymer ion ratio) are also used to determine {dollar}rm Msb{lcub}n{rcub}{dollar} for polystyrene (PS), through the generation of a calibration curve. The quantification of endgroup functionalization by TOF-SIMS is investigated using intact oligomer signals from a model PS system. Quantification is shown to be possible only after the relative signal intensities of functionalized and unfunctionalized oligomers have been determined. Desorption and ionization processes are probed using novel sample preparation methods and by employing multiphoton ionization sputtered neutral mass spectrometry (MPI-SNMS). TOF-SIMS is also employed to follow polymerization processes and evaluate polymerization mechanisms. Three examples are shown, specifically for the synthesis of polydimethylsiloxane and poly(arylene ether ketone), and the hydrogenation of polybutadiene.; A standard protocol for the preparation of polymeric samples for MALDI-MS analysis is given. Polymers up to 49 kDa are analyzed with {dollar}rm Msb{lcub}n{rcub}{dollar} in good agreement with gel permeation chromatography (GPC). Variation in laser intensity is demonstrated to influence the molecular weight distribution of intact oligomers, most significantly for low molecular weight polymer. The capabilities of the linear and reflectron analyzer mode are also compared. Furthermore, using MALDI-MS, the endgroup composition of PS is demonstrated not to have a significant effect on the ion yield.; Both XPS and TOF-SIMS are used to evaluate a block copolymer with PS and teflon-like blocks. Factors such as PS chain length, annealing, and film thickness are varied to investigate their effect on the surface composition (or the extent of surface segregation) of the film. The results allow comparison and evaluation of the sampling depths and sensitivity ofthe two techniques.
机译：新型聚合材料的特征在于飞行时间二次离子质谱（TOF-SIMS），基质辅助激光解吸质谱（MALDI-MS）和X射线光电子能谱（XPS）。除了深入了解聚合过程外，结果还为比较，评估和开发上述分析技术的功能提供了基础。使用TOF-SIMS，可以鉴定和评估低质量区域（{dollar} <{dollar} 500 Da）中的特征片段信号和高质量区域（500-10,000 Da）的完整寡聚物。使用完整的低聚物计算出{rm} rm Msb {lcub} n {rcub} {dollar}值。片段信号（端基/聚合物离子比）也用于通过生成校准曲线来确定聚苯乙烯（PS）的rm Msb {lcub} n {rcub} {dollar}。使用来自模型PS系统的完整低聚物信号研究了TOF-SIMS对端基官能化的量化。显示只有在确定了官能化和未官能化的低聚物的相对信号强度后，量化才是可能的。使用新颖的样品制备方法和多光子电离溅射中性质谱法（MPI-SNMS）探测了解吸和电离过程。 TOF-SIMS还用于跟踪聚合过程并评估聚合机理。显示了三个实例，特别是用于聚二甲基硅氧烷和聚（亚芳基醚酮）的合成以及聚丁二烯的氢化。给出了制备用于MALDI-MS分析的聚合物样品的标准方案。使用{dollar} rm Msb {lcub} n {rcub} {dollar}分析高达49 kDa的聚合物，与凝胶渗透色谱法（GPC）高度吻合。结果表明，激光强度的变化会影响完整低聚物的分子量分布，对于低分子量聚合物而言最明显。还比较了线性和反射电子分析仪模式的功能。此外，使用MALDI-MS证明PS的端基组成对离子收率没有明显影响。 XPS和TOF-SIMS均用于评估含有PS和聚四氟乙烯类嵌段的嵌段共聚物。改变诸如PS链长，退火和膜厚等因素，以研究它们对膜的表面组成（或表面偏析程度）的影响。结果允许比较和评估两种技术的采样深度和灵敏度。

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  • 作者

    Belu, Anna Marie.;

  • 作者单位

    The University of North Carolina at Chapel Hill.;

  • 授予单位 The University of North Carolina at Chapel Hill.;
  • 学科 Chemistry Analytical.; Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 1994
  • 页码 170 p.
  • 总页数 170
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;高分子化学（高聚物）;
  • 关键词

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