Moisture absorption and wet-adhesion properties of resin transfer molded (RTM) composites containing elastomer-coated glass fibers
Moisture absorption and wet-adhesion properties of resin transfer molded (RTM) composites containing elastomer-coated glass fibers
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含有弹性体涂层玻璃纤维的树脂传递模塑 (RTM) 复合材料的吸湿性和湿粘合性能
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Altan
中科院分区：
文献类型：
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作者：
H. Barraza;Levent Aktas;Y. Hamidi;John Long;E. O’Rear;M. Altan
在恒温(45℃)下对玻璃纤维/环氧复合材料进行了瞬时吸水实验，考察了不同浆料的玻璃纤维/环氧复合材料的水解稳定性和湿粘性能。与对照(未上浆)样品相比，较低的有效扩散系数值与整体机械性能的改善相关，并揭示了通过使用明显疏水的纯聚合物来改变玻璃纤维表面能量特性的重要性。在具有商业施胶的复合材料中，在无机增强材料上形成的胶束聚苯乙烯和苯乙烯-异戊二烯涂层形成的界面似乎比有机硅烷/基质界面具有更高的防潮性能。这一事实通过比较它们在性能保持方面的有效性得到了证实，这表明相对于未涂覆的复合材料，在干燥状态下以及在饱和水后，其力学性能(例如，极限拉伸强度、硬度和层间剪切强度)都有所提高。工业浆料在潮湿条件下湿粘性能差可能是由于这些涂料中存在较高的惰性物质含量所致。断口分析与前人关于无涂层复合材料灾难性失效的观察结果一致，表明界面脱粘、纤维的大量拔出和基体银纹是导致复合材料整体失效的主要原因。商用和弹性体涂层复合材料的失效表面也显示出纤维拔出的区域，但在这种情况下，基质残留物留在纤维表面，产生更粗糙的外观。良好的纤维-基质粘附性，特别是在胶束涂层的复合材料中，也表现为存在毛刺和更曲折的破坏路径。
Transient water sorption studies were carried out at constant temperature (45 °C) to assess the hydrolytic stability and wet-adhesion properties of glass fiber/epoxy composites having different sizings. Lower effective diffusivity values correlated with improved overall mechanical performance in relation to the control (unsized) samples, and revealed the importance of changing the surface energy characteristics of glass fibers by using distinctively hydrophobic pure polymers. Admicellar polystyrene and styrene-isoprene coatings formed over the inorganic reinforcement appear to create an interface with much higher resistance to moisture attack than the organosilane/matrix interface in composites with commercial sizing. This fact was corroborated by comparing their effectiveness in property retention, which showed the mechanical property (e.g. ultimate tensile strength, stiffness and interlaminar shear strength) increased with respect to the uncoated composites in the dry state as well as after water saturation. Poor wet-adhesion properties of commercial sizings in humid conditions could perhaps be attributed to higher contents of inert material present in these coatings. Fractography analysis was consistent with the previous observations regarding catastrophic failure in composites without coating, and suggested that interfacial debonding, extensive fiber pullout and matrix crazing were the major contributors to the overall failure mechanism. Failed surfaces of both commercial and elastomer-coated composites also showed areas with fiber pullout, but in this case, matrix residues remained on the fiber surfaces, yielding a much rougher appearance. Good fiber-matrix adhesion, particularly in admicellar-coated composites, was also revealed by the presence of hackles and more tortuous failure paths.