Papers by Keyword: Antifoaming Agent

Abstract: Gemini surfactant acetylene glycol polyethers and polyhydrosilicone oil were used as raw materials to generate the acetylene glycol surfactants with defoaming, antifoaming properties, and polyether modification through a hydrolyzation reaction. A novel silicone surfactant based on acetylene glycol-modified polyoxysilane, which has the advantages of low surface tension and good water solubility. Its structure characterized by infrared. Finally, the new silicone surfactant prepared was emulsified with a composite emulsifier, and a new concrete defoamer was prepared by a mechanical method. The defoaming performance, foam suppression performance and surface tension were tested. The results showed that the new silicone surfactants contained functional groups of acetylene glycol and siloxane. The composite emulsifiers were Span40 and Tween60, which the HLB value was 10, the amount was 5% and the emulsification time was 30 minutes. The prepared new concrete defoamer has good defoaming and antifoaming properties with a low surface tension.

Abstract: This paper presents the experimental investigation to enhance the mechanical properties of Polymer Modified Concrete (PMC) incorporating Styrene Butadiene Rubber (SBR) and describes the potential of using PMC as a structural material. PMC has been used for many years as an over layer in the bridges deck or for the repairing the defected concrete structures subjected to marine environment. But, because of low compressive strength due to foaming phenomenon, PMC has not been considered as a structural concrete. In this study, a range of investigations including sensitivity of PMC to water cement ratio, the effect of SBR proportion on compressive strength and modulus of rupture, selection of the proper antifoaming agent, the effect of various curing methods on compressive strength, proper mix design of PMC to achieve medium to high compressive strength are carried out. Also, the instructions for casting PMC are composed which can be stated as a standard for mixing and curing procedure of PMC. Results show that increasing the proportion of latex in PMC causes the strength reduction. But, using appropriate antifoaming agent (defoamer) and proper curing method, the mechanical properties can be recovered remarkably.

Abstract: This first part of this paper will introduce the mechanical-dynamical properties of polysiloxane defoamer thoroughly. Defoamers or foam breakers are added to eliminate the existing foam and usually act on the outer surface of the foam because a bubble is a closed system and the defoamer can only reach the outer surfaces. Then, some of synthesis methods and compounds under real application conditions are given, such as synthesis of methyl hydrogen silicone oil, synthesis methods of polyether and compounds of polyether modified polysiloxane defoamer.