Study On High Performance Dealcoholized RTV-1 Silicone Sealant

The proportion of dealcoholized RTV-1 silicone sealant is growing for its Environment- friendly property, non-corrosive, without odor and keeps well in the harsh environment for physical and electrical properties, but the curing speed of the sealant slows down and the storage stability is poor. In this thesis, in order to acquire dealcoholized RTV-1 silicone sealant with good all-around properties, a series of research on the main component of the sealant were carried out. At the same time, the effect of each component on the storage stability,cure rate and tensile strength were explored.Firstly, the nano-CaCO₃, crosslinking agent, catalyst and scavenger were studied in order to find the factor having the greatest impact on the storage stability of the sealant by orthogonal experiments. The results show that, the sorts of nano-CaCO₃ have a significant effect on the shelf life based on the selection of materials in this issue. The surface properties of nano-CaCO₃ were characterized through SEM and contact angle. The result comes out that the nano-CaCO₃ with a good surface treatment can contribute to the storage stability of the sealant. The properties of silicone sealant have been changed very little after aging at 80 degrees for three days. In addition, the tensile strength of the sealant was 2.9MPa and the tack free time is 15min with 100phr nano-CaCO₃ of 100nm in the basic composition of sealant.Secondly, a series of exploration were conducted on the types and amounts of crosslinking agent. The results show that the storage performance of the sealant was improved when the crosslinking agents were increased properly. At the same time, we found that the proportion of crosslinking agent had an effect on the process performance of this composition. The adhesive generated a large thickening in the preparation process when A-171's content was 4phr, it required slow mixing for 5min to reduce the peak viscosity. Moreover, the best proportion of crosslinking agent was obtained. When A-171's content was 2phr, the curing rate of sealant was improved significantly as well the storage performance.Lastly, the effect of coupling agents on the adhesive strength, the curing rate and the yellowing resistance were studied. The results show that the shear strength was improved obviously with coupling agents containing amino, but the tack-free time was reduced and the yellowing resistance was worse than before. We can not only ensure the good bonding strength but also good yellowing resistant property through mixture of the crosslinking agent.