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聚氨酯密封胶的拉伸剪切强度进行测定

  • 发布时间 : 2023-2-27 9:30:48
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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.

聚氨酯密封胶的拉伸剪切强度进行测定

(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 : 2023-2-27 9:30:48
  • Views:
Information

       对有机硅高固含聚氨酯密封胶的拉伸剪切强度进行测定。根据试验方案2.3.1进行试验并测定热老化前后的拉伸剪切强度,拉伸剪切试板上的涂层形貌分别如图5-4所示。由上图可知,热老化前拉伸剪切试板的破坏方式为粘附破坏(50%)和涂层内聚破坏(50%),测得5组搭接剪切强度的平均值为3.55 MPa;热老化后,高固含有机硅的目视可见破坏为内聚破坏(前两块试样可能是因为在试验过程中涂抹聚氨酯密封胶后粘结不紧密或聚氨酯密封胶过少导致,原始数据中有两组剪切力值非常低(去除)),测得老化后拉伸剪切强度平均值为4.39 MPa,变化较小。表明在高温下涂层进一步发生交联,胶粘剂与基材分子间成键,增强了聚氨酯密封胶与金属基材之间的结合力。涂层完全覆盖于金属表面,可以起到保护作用。因此对其耐温性做进一步研究。

       取固化后的有机硅高固含涂层进行TG-D S C试验,结果如图5-5所示。有机硅高固含聚氨酯密封胶的热失重主要分为三个阶段的变化。第一阶段:当温度低于200 ℃时,涂层的Tg曲线平稳,趋于一条水平线,涂层质量仅下降0.35%,涂层质量下降的原因主要是水分和低分子物质的挥发导致。第二阶段:当温度在380℃左右时,涂层质量下降稍明显,是由于涂层的分子链上的侧基甲基发生氧化反应和端经基发生水解反应断裂所导致。第三阶段:在500580 ℃时,涂层质量急剧下降,下降为原涂层质量的50%,在这个温度段,聚氨酯密封胶进一步发生分解,分子主链分解,聚氨酯密封胶失效。采用外推法进行线性拟合来计算涂层的分解温度,当温度在200350 ℃时,涂层质量的降幅较为平缓。选择该温度区间作为第一条直线的拟合区间。同时由DSC曲线可知,涂层的最大吸热峰对应的温度为525 ℃。因此,选择500550℃作为第二条直线的拟合温度区间,拟合结果如表5-2所示。这两条拟合直线的交点对应的温度为472 ℃,该温度即为涂层的分解温度。此外,在200 ℃时,涂层的失重率仅为0.35%。因此,我们可以得出结论:该涂层的耐热性较好。www.sdyuantai.com

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