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Physicochemical studies of expandable polystyrene beads and foam as applicable in lost foam castings.

机译：可发泡聚苯乙烯珠粒和泡沫的理化研究，适用于消失模铸件。

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摘要

Expandable polystyrene (EPS) is the preferred raw material for making polystyrene foam patterns that finds use in various applications, including as a construction material for buildings, spacecraft insulation, and as pattern mold in metal casting processes. Thus, information regarding the physicochemical behavior of EPS could be used for material and process development. In this study, the decomposition kinetics and gas diffusion characteristics of EPS foams have been investigated.;The goal of the kinetic study was to understand the effects of heating rate and gaseous environment on the decomposition behavior of EPS. Laboratory-scale kinetic experiments (both low and high heating rates) were carefully designed to collect pyrolysis data that were later used to estimate values for kinetic parameters, including activation energy and pre-exponential constant. A thorough review of literature on the available kinetic models have been presented and discussed. During the course of this study, a simple, yet effective, fast pyrolysis technique has been demonstrated for studying decomposition kinetics of various materials, including polymers and bio-mass.;Diffusion studies focused towards understanding the gas diffusion behavior through expanded polymeric foams from a multiscale perspective. An experimental technique was developed to collect gas transmission data for both monolithic polymer films and expanded foams. An existing coarse multiscale model available in the literature was further developed to account for the diffusion anomalies due to certain morphological features of the foam. The experimental data was utilized to validate the multiscale behavior and estimate the fractional contribution of the individual diffusion mechanisms. Results highlight the significance of the multiscale model in exploring and understanding the microstructure of the foam.
机译：可膨胀聚苯乙烯（EPS）是用于制造聚苯乙烯泡沫塑料图案的首选原材料，可用于多种应用，包括用作建筑物的建筑材料，航天器绝缘材料以及金属铸造工艺中的图案模具。因此，有关EPS的理化行为的信息可用于材料和工艺开发。本研究对EPS泡沫的分解动力学和气体扩散特性进行了研究。动力学研究的目的是了解加热速率和气体环境对EPS泡沫分解行为的影响。精心设计了实验室规模的动力学实验（低和高加热速率）以收集热解数据，这些数据随后用于估算动力学参数的值，包括活化能和指数前常数。已经提出并讨论了有关可用动力学模型的文献的详尽综述。在本研究过程中，已证明了一种简单而有效的快速热解技术，可用于研究各种材料（包括聚合物和生物质）的分解动力学。扩散研究的重点是通过气体膨胀来理解聚合物泡沫的气体扩散行为。多尺度的观点。开发了一种实验技术来收集整体式聚合物薄膜和膨胀泡沫的气体传输数据。进一步开发了文献中可用的现有粗略多尺度模型，以解释由于泡沫的某些形态特征而引起的扩散异常。实验数据被用来验证多尺度行为并估计各个扩散机制的分数贡献。结果突出了多尺度模型在探索和理解泡沫微观结构中的重要性。

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  • 作者

    Kannan, Pravin.;

  • 作者单位

    Tennessee Technological University.;

  • 授予单位 Tennessee Technological University.;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 140 p.
  • 总页数 140
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化工过程（物理过程及物理化学过程）;
  • 关键词

  • 入库时间 2022-08-17 11:38:29

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