低模量脱醇型室温硫化硅橡胶的研制

Preparation of a Low Modulus Dealcoholized Room-Temperature Vulcanized Silicone Rubber

以α,ω-二羟基聚二甲基硅氧烷为基础聚合物,纳米碳酸钙为补强填料,二甲基硅油、MDT硅油为增塑剂,甲基三甲氧基硅烷为交联剂,甲基乙烯基二甲氧基硅烷为扩链剂,添加催化剂、粘接促进剂等制得脱醇型单组分室温硫化硅橡胶。研究了纳米碳酸钙种类、增塑剂组分及用量、扩链剂用量对硅橡胶性能的影响。结果表明,补强填料选择以脂肪酸和硅烷偶联剂复配物作表面处理剂的纳米碳酸钙较佳;单独以二甲基硅油作增塑剂时,随着二甲基硅油用量由0增加到40份,硅橡胶的拉伸强度由1.67 MPa降至0.92 MPa,拉断伸长率由523%升至807%,拉伸模量由0.72 MPa降至0.32 MPa。二甲基硅油的较佳用量为20份;以MDT硅油与二甲基硅油复配物作增塑剂、增塑剂总用量固定为20份的条件下,随着MDT硅油质量比的升高,硅橡胶的拉伸强度和拉伸模量先降后升,拉断伸长率先升后降,挤出性逐渐降低。增塑剂采用10份MDT硅油与10份二甲基硅油复配较佳;向体系中加入扩链剂并不断提高用量,硅橡胶的表干时间延长,拉伸模量降低,拉断伸长率先升后降。扩链剂的较佳用量为1份;在上述优选条件下制得的硅橡胶综合性能较佳,拉伸模量为0.26 MPa,拉断伸长率为876%,表干时间为50 min,可作为低模量有机硅密封胶用于道路嵌缝填缝和保温装饰一体化板填缝密封等领域。

The dealcoholized one-component room temperature vulcanized silicone rubber was prepared with α,ω-dihydroxy polydimethylsiloxane as the base polymer, nano calcium carbonate as the reinforcing filler, dimethyl silicone oil and MDT silicone oil as the plasticizer, methyltrimethoxysilane as the crosslinking agent, methylvinyldimethoxysilane as the chain extender, and catalyst and adhesion promoter. The effects of the types of nano calcium carbonate, components and content of plasticizer, chain extender dosage on the properties of silicone rubber were studied. The results show that the nano-calcium carbonate with fatty acid and silane coupling agent as surface treatment agent is the best choice. When dimethyl silicone oil is used as plasticizer alone, the tensile strength of silicone rubber decreases from 1.67 MPa to 0.92 MPa, the elongation at break increases from 523% to 807%, and the tensile modulus decreases from 0.72 MPa to 0.32 MPa when the dimethyl silicone oil increases from 0 to 40 parts. When dimethyl silicone oil is 20 parts, the compounding of MDT silicone oil and dimethyl silicone oil as plasticizer(20 parts), as the mass ratio of MDT silicone oil increasing, the tensile strength and tensile modulus of silicone rubber decreases firstly and then increases, the tensile elongation increases firstly and then decreases, and the extrudability decreases gradually. The optimal plasticizer is 10 parts MDT silicone oil mixed with 10 parts dimethyl silicone oil. By adding chain extender into the system and increasing its dosage, the silicone rubber has extended surface drying time, the reduced tensile modulus, and the elongation at breaking firstly increased and then decreased. The optimal chain extender is 1 part. The silicone rubber prepared has good comprehensive performance, with tensile modulus of 0.26 MPa, elongation at break of 876% and surface drying time of 50 min, which is used as a low modulus silicone sealant for road caulking, joint sealing and integrated insulation decorations.