Thermo-mechanical Responses of Fiber-reinforced Epoxy Composites Exposed to High Temperature Environments. Part I: Experimental Data Acquisition
Thermo-mechanical Responses of Fiber-reinforced Epoxy Composites Exposed to High Temperature Environments. Part I: Experimental Data Acquisition
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DOI：
10.1177/0021998310373511
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发表时间：
2010-12-01
影响因子：
2.9
通讯作者：
Edwards, G.
中科院分区：
文献类型：
--
作者：
Kandare, E.;Kandola, B. K.;Edwards, G.
这是关于纤维增强复合材料在高温下的热机械响应的系列论文的第一部分，报告了作为输入数据所需的实验结果，以验证正在开发并将在后续论文中讨论的动力学、热传递和热机械模型。这里讨论了用于确定物理、热和机械性能的实验技术及其对特定模型的意义。用于改善玻璃纤维增强环氧复合材料防火性能的阻燃体系是一种纤维素炭化剂和一种相互作用的膨胀剂三聚氰胺磷酸盐的组合。热重法用于获得动力学参数，并评估与温度相关的物理性质，如密度、导热系数和比热容量，使用其他技术确定。在热流密度为50kW/m(2)的锥形量热计下进行可燃性评估时，使用热电偶测量样品的厚度。为了研究它们的热机械行为，将复合材料暴露在不同的加热环境中，并测定了它们在冷却到环境温度后的残余弯曲弹性系数。在10Ac/min的低升温速率和对流条件下，阻燃添加剂对力学性能保持率的影响很小，说明阻燃剂对树脂的玻璃化转变温度没有影响。另一方面，在加热速度约为200AC/分钟的锥形量热计的辐射热下，阻燃试件在40-S曝光后显示出60%的弯曲弹性系数保留率，而对照样品在将试件冷却到环境温度后观察到20%的保留率。
This first part of a series of papers on the thermo-mechanical responses of fiber-reinforced composites at elevated temperatures reports the experimental results required as input data in order to validate the kinetic, heat transfer, and thermo-mechanical models being developed and to be discussed in subsequent papers. Here the experimental techniques used for the determination of physical, thermal, and mechanical properties and their significance for particular models are discussed. The fire retardant system used to improve the fire performance of glass fiber-reinforced epoxy composites is a combination of a cellulosic charring agent and an interactive intumescent, melamine phosphate. Thermogravimetry is used to obtain kinetic parameters and to evaluate the temperature-dependent physical properties such as density, thermal conductivity, and specific heat capacity, determined using other techniques. During flammability evaluation under a cone calorimeter at 50 kW/m(2) heat flux, thermocouples are used to measure temperatures through the thicknesses of samples. To investigate their thermo-mechanical behavior, the composites are exposed to different heating environments and their residual flexural modulus after cooling to ambient temperatures determined. At a low heating rate of 10AC/min and convective conditions, there was a minimal effect of fire retardant additives on mechanical property retention, indicating that fire retardants have no effect on the glass transition temperature of the resin. On the other hand, the fire-retarded coupons exposed to a radiant heat from cone calorimeter, where the heating rate is about 200AC/min, showed 60% retention of flexural modulus after a 40-s exposure, compared to 20% retention observed for the control sample after cooling specimens to ambient temperatures.