Low pressure plasma treatment of CFRP substrates for adhesive bonding: an investigation of joint durability under severe temperature-moisture conditioning
Low pressure plasma treatment of CFRP substrates for adhesive bonding: an investigation of joint durability under severe temperature-moisture conditioning
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DOI：
10.1016/j.ijadhadh.2020.102592
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发表时间：
2020-06-01
影响因子：
3.4
通讯作者：
Mandolfino, C.
中科院分区：
文献类型：
--
作者：
Pizzorni, M.;Lertora, E.;Mandolfino, C.
这项工作报告了定量评估使用增韧的环氧胶在CFRP基材上制造的胶接接头的老化行为。采用低压等离子体(LPP)处理，采用空气和纯氧作为工艺气体，改变功率和曝光时间等工作参数。在标准的实验室条件下进行了初步测试活动，以评估单搭接接头(SLJ)的剪切强度，比较了LPP处理的有效性和粘结物的传统机械磨损。即使在这个早期阶段，实验结果也强调了这种物理方法是如何提供具有竞争力的磨损性能的，从而显著提高了抗剪切能力。选择四组LPP处理条件，然后进行加速老化(包括56个循环，5个HAT T=70℃，RH>；90%和5h，每个循环T=-40℃)。将它们的行为与磨损关节的行为进行比较，作为参考。为了评估CFRP-环氧胶粘剂体系在加速老化条件下的耐久性，平行进行了拉伸剪切强度(TSS)试验和楔形劈裂试验(WT)。实验结果表明，即使在严重的老化条件下，对CFRP基材进行低压等离子体处理也能提高粘接接头的短期质量，并增强其耐久性。
This work reports a quantitative evaluation of the aging behavior of adhesively bonded joints manufactured using a toughened epoxy adhesive applied on CFRP substrates. Low-pressure plasma (LPP) treatment was employed, adopting air and pure oxygen as process gases and varying working parameters such as power and exposure time. A preliminary testing campaign was performed under standard laboratory conditions to evaluate shear strength of single-lap joints (SLJ), comparing effectiveness of LPP treatments to a traditional mechanical abrasion of the adherends. Even at this early stage, experimental findings highlighted how this physical method provides for competitive performance over abrasion, resulting in a remarkable enhancement of the shear resistance. Four sets of LPP-treatment conditions were selected and then subjected to accelerated aging (consisting of 56 cycles of 5 hat T = 70 degrees C, RH>90% and 5 h at T = -40 degrees C each). Their behavior was compared to that of abraded joints, employed as a reference. To assess the durability of the CFRP-epoxy adhesive system under accelerated aging conditions, tensile shear strength (TSS) testing and wedge cleavage test (WT) were performed in parallel. The experimental results showed that low-pressure plasma treatment of the CFRP substrates results in increased short-term quality of the adhesive joint as well as in enhancement of its durability even under severe aging conditions.