摘要：
The durability of sealing materials for road joint plays an important role in service of roads. The durability of silicone rubber sealant was studied by way of the testing its properties of liquid resistance, chemical resistance, alternate freezing and thawing stability and adhesion at various temperatures. The results evident that silicone rubbers have good thermal characteristics, chemical resistance, and environmental stability, which make this class of materials very attractive selection for use in the outdoor applications.
摘要：
This investigation aimed to study the interaction between concrete substrate and silicone rubber sealant. Several surface treatments were applied in order to obtain different levels of surface roughness in concrete substrates. The bond tensile test showed that abrasion and solvent cleaning methods improved the bond strength relative to that of untreated substrates. The effects of silane coupling agents on the bond strength was studied via two methods of application of the coupling agent, namely, (a) pre-treatment of concrete substrate in an aqueous solution of silane, and (b) adding silane to the silicone rubber sealant as an integral blend additive. No significant differences in bonding values were noted between the two methods. An increase in the amount of silane coupling agent increased the bond strength of the silicone rubber sealant, but beyond a certain point, further increases in the amount of silane lowered the bond strength. As the amount of silanes increased, the failure mode of the samples changed from adhesive failure to cohesive failure. Scanning electron microscopy and contact angle methods were employed to investigate the interface. The results strongly suggest that interface adhesion and treatments are crucial factors in creating a durable bond interface between substrate and sealant.
摘要：
A cost-effective better performing silicone waterproofing agent interpenetrating polymer network coating for the protection of concrete has been developed. The working mechanism of the silicone polymer on the concrete was revealed and the effect of the material on the water absorption, chloride diffusion coefficient of concrete was analyzed. The results showed that the deep penetration of silicone material formed a hydrophobic layer and provides an effective protection against water corrosion and chloride ingress. A long-term protection can be guaranteed in case the surface of the concrete is waterproofing.
摘要：
Avinyl functional microemulsion was successfully prepared via polycondensation between polysiloxane prepolymer and a modifier (vinyl silane coupling agent with alkoxy groups). The polysiloxane prepolymer was prepared by ring-opening of D<inf>4</inf> (octamethylcyclotetrasiloxane). The structure and properties of vinyl functional microemulsion were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), photon correlation spectroscopy (PCS). FTIR Spectroscopy result showed that vinyl groups were successfully introduced into the polysiloxane molecules. The variation in pH, amount of vinyl coupling agent and catalyst were studied in relation to the properties of the final microemulsion. The results indicated that under strong acidic more coagulum and higher percentage of conversion occurred in the microemulsion. TEM results also revealed that particles are densely packed in strong acidic condition but become sparsely distributed in weak acidic condition. An increase in the vinyl coupling agent content leads to an increase in formation of coagulum and in particle size, but it lowers the particle size distribution. The smaller ratio of the average surface coverage of surfactant leads to higher amount of coagulation which is in linear dependence to the increased amount of vinyl coupling agent modifier. Photon correlation spectroscopy results show that increasing the amount of vinyl coupling agent modifier increases the particles size, while reduces the particles size distribution. It can be concluded that the coagulum weight fraction increases linearly with higher amount of catalyst. An increase in the vinyl coupling agent modifier leads to an increase in the coagulum. The microemulsion shows stability when the amount of catalyst is about 3.0-4.0 wt%.
