Effect of Network Parameters on the Properties of Polycyanurate Thermosetting Polymers

二氰酸酯/聚氰脲酸酯热固性聚合物是一类相对较新的高性能材料，由于其优异的介电性能而用于电子和复合材料应用。 本研究计划将研究网络参数对这些材料性能的影响。 双酚A二氰酸酯的一系列低聚物（三聚体、五聚体等）将被合成，并且转化率与性能的关系将与单体的转化率与性能的关系进行比较。 由于氰酸酯的转化率与网络参数之间的关系在不同尺寸的低聚物反应时会有所不同，并且由于不同低聚物在完全转化时的结构是相同的，因此可以确定网络参数的影响。 这种新的方法克服了通常遇到的复杂性时，在热固性系统中出现的重复单元的结构时，网络参数的影响进行研究。 检查的性质将包括玻璃化转变温度和体积。 各种低聚物反应在凝胶化时的转化率将产生关于反应中成环量的信息。 实验技术将包括差示扫描量热法、热分析法、核磁共振光谱法、高效液相色谱法和凝胶渗透色谱法。 这项工作将有助于我们理解玻璃态自由体积的起源。 这对于二氰酸酯材料特别重要，因为与自由体积相关的吸湿性似乎不利地影响它们的热稳定性。 所提出的工作也是重要的热固性性能的优化和模型的发展，预测的时间和温度的依赖性的玻璃质热固性材料的复合材料中的潜在用途。

Dicyanate ester/polycyanurate thermosetting polymers are a relatively new class of high-performance materials used in electronic and composite applications, because of their excellent dielectric properties. This research program will investigate the effect of network parameters on the properties of these materials. A series of oligomers of bisphenol A dicyanate (trimer, pentamer, etc.) will be synthesized, and conversion- versus-property relationships will be compared with that of the monomer. Since the relationships between conversion of cyanate and network parameters will differ when different size oligomers are reacted, and since the structure at full conversion is identical for the different oligomers, the effects of network parameters can be determined. This novel approach overcomes complications generally encountered when studying the effects of network parameters in thermosetting systems that arise when the structure of the repeat unit is charged. The properties examined will include the glass-transition temperature and the volume. The conversion at gelation for the reaction of the various oligomers will yield information concerning the magnitude of ring formation in the reaction. Experimental techniques will include differential scanning calorimetry, dilatometry, nuclear magnetic resonance spectroscopy, high-performance liquid chromatography, and gel permeation chromatography. %%% This work will help our understanding of the origins of free volume in the glassy state. This is particularly important for dicyanate ester materials since moisture absorption, which is related to free volume, appears to adversely affect their thermal stability. The proposed work is also important for the optimization of thermosetting properties and for the development of models which predict the time and temperature dependence of glassy thermosetting materials of potential use in composite materials.