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首页> 外文期刊>Journal of Applied Polymer Science >CURING KINETICS AND THERMAL PROPERTIES OF VINYL ESTER RESINS
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CURING KINETICS AND THERMAL PROPERTIES OF VINYL ESTER RESINS

机译：乙烯基酯树脂的固化动力学和热性能

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The curing kinetics of dimethacrylate-based vinyl ester resins were studied by scanning and isothermal DSC, gel time studies, and by DMTA. The rate of polymerization was raised by increased methyl ethyl ketone peroxide (MEKP) concentration but the cocatalyst, cobalt octoate, retarded the reaction rate, except at very low concentrations. By contrast, the gel time was reduced for all increases in either peroxide or cobalt concentration. This contradictory behavior was explained by a kinetic scheme in which the cobalt species play a dual role of catalyzing the formation of radicals from MEKP and of destroying the primary and polymeric radicals. The scanning DSC curves exhibited multiple peaks as observed by other workers, but in the present work, these peaks were attributed to the individual influence of temperature on each of fundamental reaction steps in the free radical polymerization. Physical aging appeared to occur during the isothermal polymerization of samples cured below the ''fully cured'' glass transition temperature (T-g). For these undercured materials, the difference between the DSC T-g and the isothermal curing temperature was approximately 11 degrees C. Dynamic mechanical analysis of a partially cured sample exhibited anomalous behavior caused by the reinitiation of cure of the sample during the DMTA experiment. For partially cured resins, the DSC T-g increased monotonically with the degree of cure, and this dependence was fitted to an equation related to the Couchman and DiBenedetto equations. (C) 1997 John Wiley & Sons, Inc. [References: 50]
机译：通过扫描和等温DSC，胶凝时间研究和DMTA研究了基于二甲基丙烯酸酯的乙烯基酯树脂的固化动力学。聚合速率通过提高甲基乙基酮过氧化物（MEKP）的浓度而提高，但助催化剂辛酸钴抑制了反应速率，除非浓度非常低。相反，由于过氧化物或钴浓度的所有增加，胶凝时间减少了。通过动力学方案解释了这种矛盾的行为，其中钴物种起催化由MEKP形成自由基以及破坏伯自由基和聚合自由基的双重作用。扫描的DSC曲线显示出其他工人观察到的多个峰，但是在当前工作中，这些峰归因于温度对自由基聚合中每个基本反应步骤的单独影响。在低于“完全固化”玻璃化转变温度（T-g）固化的样品进行等温聚合期间，似乎发生了物理老化。对于这些未充分固化的材料，DSC T-g与等温固化温度之间的差约为11摄氏度。部分固化的样品的动态力学分析显示出异常行为，这是由于在DMTA实验期间重新固化样品而引起的。对于部分固化的树脂，DSC T-g随着固化程度单调增加，并且这种依赖性适合与Couchman和DiBenedetto方程有关的方程。 （C）1997 John Wiley＆Sons，Inc. [参考：50]

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