Post-Curing Effects on Marine VARTM FRP Composite Material Properties for Test and Implementation
Post-Curing Effects on Marine VARTM FRP Composite Material Properties for Test and Implementation
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DOI：
10.1115/1.2128425
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发表时间：
2006
影响因子：
1.2
通讯作者：
J. Cain;N. Post;J. Lesko;S. Case;Yin-Nian Lin;J. Riffle;P. Hess
中科院分区：
文献类型：
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作者：
J. Cain;N. Post;J. Lesko;S. Case;Yin-Nian Lin;J. Riffle;P. Hess
结构复合材料越来越多地被用于许多大型海军和民用结构中，在这些结构中，至关重要的是它们的长期性能是可预测的，它们的可变性在结构的整个生命周期中是可以定义的。然而，这些性能可能会受到树脂固化程度的影响，特别是对于室温固化体系。因此，这项研究定义了使用真空辅助树脂传递模塑(VARTM)方法制造的E-玻璃纤维/乙烯基酯纤维增强聚合物(FRP)复合材料的后固化效应，这种方法是美国海军用于舰船结构的典型方法。通过不同水平的后固化温度和持续时间来区分复合材料，并在后固化后的不同时间点检查推进固化的效果。为了跟踪强度、刚度、失效应变、蠕变和疲劳性能随时间的变化规律，分别在后固化后的1、10、30、100和300天，对来自各层后固化的伪准各向同性[0/+45/90/-45/0]S和角铺层压板[±45]2S试件进行了检测。同时，使用FTIR(傅里叶变换红外光谱)对基质聚合物进行检测，以直接评估转化率。还进行了动态力学分析和收缩测量，以评估玻璃化温度和在后固化过程中发生的收缩量，以及在规定的老化时间内固化水平的提高。结果表明，在93℃后固化后，乙烯基酯齐聚物的转化率为80%，苯乙烯的转化率为90-95%。观察到，在室温下储存300天后，未后固化样品的转化率接近93℃后固化样品的转化率。树脂为主的准静态性能受固化程度的影响较大，而纤维为主的性能受固化程度的影响不大。在固化程度相对较低的情况下，粘弹性会引起蠕变响应的较大变化，并影响疲劳性能。
Structural composites are increasingly being utilized in many large naval and civil structures where it is vital that their long-term performance be predictable and their variability definable over the life of the structure. However, these properties may be influenced by the degree of cure of the resin, particularly for room-temperature-cured systems. Thus, this investigation defines the postcure effects on E-glass/vinyl-ester fiber-reinforced polymer (FRP) composites manufactured using the vacuum-assisted resin transfer molding (VARTM) method, which are typical of those used by the US Navy for ship structures. The composites are differentiated by varying levels of postcure temperature and duration, and examined for the effects of advancing cure at various points in the time after postcure. Pseudo-quasi-isotropic [0/+45/90/-45/0]s and angle ply laminate [±45]2s samples from each level of postcure are examined at 1, 10, 30, 100, and 300 days after postcure in order to track strength, stiffness, failure strain, creep, and fatigue performance as functions of time. In parallel, the matrix polymer is inspected using FTIR (Fourier transform infrared spectroscopy) to directly assess the degree of conversion. Dynamic mechanical analysis and shrinkage measurements are also undertaken to assess the Tg and the amount of shrinkage undergone during post-curing, as well as the advancing of the level of cure during the prescribed aging time. Results suggest that the degree of conversion is limited to 80% for the vinyl-ester oligomer and 90-95% for styrene following a postcure of 93°C. It is observed that after 300 days of ambient storage the nonpostcured samples approach the degree of conversion exhibited by those postcured at 93°C, as measured by FTIR. Resin dominated quasi-static properties are greatly affected by the degree of cure, whereas fiber dominated properties are not. Where the degree of cure is comparatively low, viscoelastic properties cause greater changes in creep response as well as influencing fatigue performance.