酮肟基硅烷扩链/交联低模量有机硅密封胶的制备及性能

以酮肟基硅烷为扩链/交联体系,以自制的含氰基和仲胺基的新型硅烷偶联剂为增粘剂,制备挤出流动性良好、表干时间短、粘接性好、模量低(100%定伸应力<0.4 MPa)、断裂伸长率高(>800%)的有机硅密封胶。讨论了扩链/交联体系、增粘剂类型及用量对有机硅密封胶表干时间、力学性能和粘接性能的影响。发现随扩链剂用量的增大,密封胶的断裂伸长率提高,但强度降低,表干时间延长。只有合理选用交联剂的用量,才能使密封胶固化交联。相对于传统的增粘剂而言,自制的增粘剂可显著提高密封胶的力学性能和粘接强度,缩短表干时间。

Preparation and Properties of Solicone Sealant with Low Modulus and High Elongation Through Chain Extend/Crosslink by Using Ketoximosilane

Silicone sealants with good extrudability, short skin over time,good adhesive properties,low modulus(100% tensile stress <0.4 MPa) and high elongation(>800%) were prepared by using ketoximosilane as chain extend/crosslink agent.Meanwhile,two novel silane coupling agents were synthesized which can be acted as adhesion promoting agent.Influences of chain extend / crosslink system and adhesion promoting agent on skin of the sealant over time,mechanical and adhesive properties of silicone sealant were investigated.The results reveal that increasing the content of chain extend agent could lead to a high elongation and low modulus,but a low tensile strength and long skin over time.Only at proper content of crosslinking agent silicone sealants can be vulcanized.The novel adhesion promoting agents promote the rate of vulcanization and enhance the mechanical properties and adhesive properties with concrete significantly,as compared to the traditional ones.