酸性腐蚀介质对聚氨酯密封胶的腐蚀

发布时间 : 2023-2-25 19:19:37
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(Summary description)Customized SILICONE STRUCTURAL SEALANT from China manufacturer refers to the adhesive with high strength, can bear large load, aging resistance, fatigue resistance and corrosion resistance, and has stable performance within the expected life. It is suitable for bearing the bonding of strong structural parts. Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for structural adhesive bonding. NEUTRAL SILICONE WETHERPROOF SEALANT from China manufacturer is a structural adhesive with waterproof function. Silicone glue refers to the adhesive based on silicone rubber. According to different functions, it can be divided into structural adhesive, potting adhesive, sealant, thermal conductive adhesive, flame retardant adhesive and so on.

酸性腐蚀介质对聚氨酯密封胶的腐蚀

(Summary description)Customized SILICONE STRUCTURAL SEALANT from China manufacturer refers to the adhesive with high strength, can bear large load, aging resistance, fatigue resistance and corrosion resistance, and has stable performance within the expected life. It is suitable for bearing the bonding of strong structural parts. Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for structural adhesive bonding. NEUTRAL SILICONE WETHERPROOF SEALANT from China manufacturer is a structural adhesive with waterproof function. Silicone glue refers to the adhesive based on silicone rubber. According to different functions, it can be divided into structural adhesive, potting adhesive, sealant, thermal conductive adhesive, flame retardant adhesive and so on.

发布时间 : 2023-2-25 19:19:37
Views:

综合图3-5 ( TG-DSC)分析可知，在100 ℃时，聚氨酯密封胶的失重率仅为0.35%; 200℃老化后，聚氨酯密封胶的拉伸剪切强度和附着性能均较好，推测聚氨酯密封胶在100 ℃的耐热性应该较好。因此，拉伸剪切试样出现附着破坏的原因可能是由于酸性腐蚀介质对聚氨酯密封胶的腐蚀以及腐蚀溶液中的水分子或氯离子渗入聚氨酯密封胶和金属基材的界面，导致其界面粘结力下降。

将聚氨酯密封胶分别涂敷于模拟件的叶根和桦槽上，随后把叶片推入桦槽内，在室温下放置一周使其完全固化。将模拟件放置于电子万能试验机上，施加压力将叶根从桦槽中推出，记录该过程的位移一负荷曲线，结果如图3-8所示。由图可知，当位移为2.5 mm时，负荷达到最大，说明聚氨酯密封胶的粘结性被破坏，最大破坏力为21 kN;此后，模拟件的拆卸过程大约需要3 kN的力值。

拆卸试验后的聚氨酯密封胶形貌如图3-9所示。从拆卸后的形貌可以看出该涂层的韧性较好，材质较软，胶层呈絮状脱落，未脱落的胶层与模拟件的附着力相对较小，用手即可将其剥离。金属基体有大部分裸露出来，未受到聚氨酯密封胶的保护，密封性能较差。

原用聚氨酯密封胶的可施工性(表干时间、实干时间)、可常温固化性满足涂敷要求，拉伸剪切强度较低，有利于后续拆卸，但与基体的粘结性差，之间容易形成缝隙。聚氨酯密封胶的流动性较差，且聚氨酯密封胶固化后体积收缩较为严重，200 ℃热老化后出现粉化现象，这会导致聚氨酯密封胶无法填满间隙，桦槽与叶根之间出现空隙，未能达到密封效果。同时，工况环境中含有腐蚀性较强的物质当温度下降至水蒸气的凝点以下，腐蚀性物质溶于水中并向聚氨酯密封胶与金属基体的连接界面渗透，降低了聚氨酯密封胶与金属基体的界面结合力，造成金属基材的腐蚀。当聚氨酯密封胶长期处于该环境中时，腐蚀产物与聚氨酯密封胶中未挥发的大分子填料相互作用，引起腐蚀产物与金属基材之间的相互咬合作用力提升，导致拆卸过程难度较大。www.sdyuantai.com

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