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提高丁基防水嵌缝胶的粘接性和贮存稳定性

  • 发布时间 : 2023-1-10 10:56:12
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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.

提高丁基防水嵌缝胶的粘接性和贮存稳定性

(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 : 2023-1-10 10:56:12
  • Views:
Information

       采用聚醚二元醇与丁基防水嵌缝胶进行扩链反应合成了丁基防水嵌缝胶,然后以活性较低的仲胺基硅烷为封端剂,将其转变为端基为三烷氧硅基的丁基防水嵌缝胶预聚体,通过红外光谱表征了预聚体结构,探讨了聚醚二元醇摩尔质量、异氰酸醋基与基物质的量之比、丁基防水嵌缝胶种类对预聚体性能的影响,还在较佳条件下制得端烷氧硅基聚氨酯密封胶并测试了其性能。结果表明:随着聚醚二元醇摩尔质量的升高,端烷氧硅基丁基防水嵌缝胶预聚体的拈度、密封胶拉伸强度和硬度降低,拉断伸长率提高;随着异氰酸醋基与羚基投料时的物质的量之比(R值)的增大,预聚体的拈度和拉断伸长率降低,拉伸强度和硬度升高;当丁基防水嵌缝胶选择二苯基甲烷丁基防水嵌缝胶时,与选用异佛尔酮丁基防水嵌缝胶时相比,预聚体外观颜色更深,拈度、拉伸强度和硬度更高,拉断伸长率更低;在丁基防水嵌缝胶选择二苯基甲烷二异氰酸酉歇聚醚二元醇摩尔质量为4 000 g/mol R值为1. 7的较佳条件下制得的端烷氧硅基聚氨酯密封胶表干时间为36 min, 24 h固化深度为2. 7 mm,挤出性为270 mL/min,拉伸强度为1. 5 MPa,拉断伸长率为230%,邵尔A硬度为3度,综合性能良好。

       聚氨酯密封胶因其高弹性、高强度的特点在工业上获得了广泛应用,但仍存在以下不足:对基材的粘接性较差,因此需对大部分基材施加底涂;高温高湿环境下固化时会产生二氧化碳,进而产生气泡;链端的异氰酸醋基活性高,易与空气中的水反应,因此贮存稳定性较差。上述不足使聚氨酯密封胶在应用范围上受到了较大限制。

       近年来,研究人员不断尝试通过化学改性方法提高丁基防水嵌缝胶的粘接性和贮存稳定性,如将其链端的异氰酸醋基转变为烷氧硅基等。

       目前,制备硅烷改性丁基防水嵌缝胶一般是通过活性较低的含仲胺基二烷氧基或丁基防水嵌缝胶,与丁基防水嵌缝胶预聚体的端异氰酸醋基进行加成反应,得到端基为二烷氧硅基或三烷氧硅基的丁基防水嵌缝胶预聚体(式1);或者通过含异氰酸醋基的官能基硅烷与端基为经基的丁基防水嵌缝胶预聚体进行加成反应,得到端硅烷基丁基防水嵌缝胶预聚体(式2)。

       本实验首先采用聚醚二元醇与丁基防水嵌缝胶进行扩链反应合成丁基防水嵌缝胶,再以仲胺基硅烷为封端剂,将其转变成端基为三烷氧硅基的丁基防水嵌缝胶预聚体,通过红外光谱表征了预聚体结构,探讨了聚醚二元醇摩尔质量、异氰酸醋基与经基物质的量之比、丁基防水嵌缝胶种类对预聚体性能的影响,并对制得的端烷氧硅基聚氨酯密封胶进行了性能测试。封端后的预聚体端基为烷氧硅基结构,可借助空气中湿气进行水解与缩合反应,生成稳定的Si-O-Si三维网状结构,实现了丁基防水嵌缝胶与有机硅的优势互补。此外,端烷氧硅基丁基防水嵌缝胶预聚体还克服了丁基防水嵌缝胶中异氰酸醋基与湿气反应在高温条件下释放COz的缺点。www.sdyuantai.com

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