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Synthesis and characterization of well-defined poly(1,3-cyclohexadiene) homopolymers and copolymers.

机译：定义明确的聚（1,3-环己二烯）均聚物和共聚物的合成和表征。

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摘要

Polymers containing poly(1,3-cyclohexadiene) were synthesized using a novel pre-formed initiator comprised of an alkyllithium and a tertiary diamine. The use of a pre-formed initiator at moderate temperatures (25°C) enabled the synthesis of high molecular weight poly(1,3-cyclohexadiene) homopolymers (⟨Mn⟩ = 50000) with narrow molecular weight distributions (⟨Mw⟩/⟨Mn⟩ = 1.20). In contrast, the use of a conventional anionic initiation approach resulted in polymerizations that lacked significant degrees of livingness, which limited the polymer molecular weights to approximately 10000. Use of the preformed initiator resulted in a reduction in the degree of both chain termination and chain transfer. In addition, the livingness of the polymerization was shown to be a function of the monomer concentration and the polymerization temperature. The regiochemistry of the polymers were shown to be dependent on the tertiary amine used in the polymerization, which provided a route for the synthesis of polymers with a microstructure rich in either high 1,2-addition (70%) or high 1,4-addition (90%). A range of analytical methods were employed to determine the stereo and regiochemistry of poly(1,3-cyclohexadiene). These methods included 1H NMR, 13C NMR, and endgroup functionalization of the propagating center with chlorotrimethylsilane. The impact of regiochemistry on the thermal properties was examined using differential scanning calorimetry. In addition, the thermooxidative properties of these poly(1,3-cyclohexadiene) polymers were characterized in a series of oxidative studies and the onset of oxidative degradation occurred at 110°C. Perfectly alternating copolymers of poly(1,3-cyclohexadiene-alt-styrene) were synthesized, and the reactivity ratios for these copolymers (r1,3CHD = 0.022, rstyrene = 0.024) were determined using a conventional Mayo-Lewis approach. The effect of aromatization and hydrogenation on the thermal properties of these copolymers was determined using thermal gravimetric analysis and differential scanning calorimetry. The synthesis of poly(1,3-cyclohexadiene) DVB coupled star-shaped polymers was performed using a convergent arm-first approach in combination with a divinylbenzene coupling agent (PDI = 1.25). Well-defined poly(1,3-cyclohexadiene-block-isoprene)-star shaped polymers were synthesized and utilized for the development of novel high temperature thermoplastic elastomers, with excellent elastomeric properties (percent elongation = 745%, tensile strength = 7.2 MPa). Atomic force microscopy in combination with differential scanning calorimetry verified the presence of microphase separation between the blocks.
机译：使用由烷基锂和叔二胺组成的新型预制引发剂合成了含聚（1,3-环己二烯）的聚合物。在中温（25°C）下使用预先形成的引发剂可以合成分子量窄的高分子量聚（1,3-环己二烯）均聚物（〈M n 〉 = 50000）权重分布（〈M w 〉 / 〈M n 〉 = 1.20）。相反，使用常规的阴离子引发方法会导致聚合反应缺乏显着的活度，从而将聚合物的分子量限制在大约10000。使用预制的引发剂会导致链终止和链转移的程度降低。另外，显示聚合的活性是单体浓度和聚合温度的函数。聚合物的区域化学性质取决于聚合反应中使用的叔胺，这为合成具有高1,2-加成（70％）或高1,4-高结构的聚合物提供了一条途径。另外（90％）。采用了多种分析方法来确定聚（1,3-环己二烯）的立体和区域化学。这些方法包括 1 H NMR， 13 C NMR，以及用三甲基氯硅烷传播中心的端基官能化。使用差示扫描量热法检查了区域化学对热性能的影响。此外，这些聚（1,3-环己二烯）聚合物的热氧化性能在一系列的氧化研究中得到了表征，氧化降解的开始发生在110°C。合成了聚（1,3-环己二烯- alt -苯乙烯）的完美交替共聚物，这些共聚物的反应比（r 1,3CHD = 0.022，r < sub>苯乙烯 = 0.024）是使用常规的Mayo-Lewis方法测定的。使用热重分析和差示扫描量热法确定了芳构化和氢化对这些共聚物的热性能的影响。聚（1,3-环己二烯）DVB偶联星形聚合物的合成是使用会聚臂先聚合法和二乙烯基苯偶联剂（PDI = 1.25）进行的。合成定义明确的聚（1,3-环己二烯-<斜体> -异戊二烯）-星形聚合物，并将其用于开发新型高温热塑性弹性体，该弹性体具有出色的弹性（伸长率= 745％） ，抗拉强度＝ 7.2MPa）。原子力显微镜与差示扫描量热法相结合，验证了块之间存在微相分离。

著录项

  • 作者

    Williamson, David Thomas.;

  • 作者单位

    Virginia Polytechnic Institute and State University.;

  • 授予单位 Virginia Polytechnic Institute and State University.;
  • 学科 Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 355 p.
  • 总页数 355
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 高分子化学（高聚物）;
  • 关键词

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