Synthesis And Properties Of Bola Polysiloanxes Modified By Butynediol-ethoxylate

Siloxane surfactants possess high surface activity,low foam property and good spreading wetting property,which can be used in many fields.In order to meet the demand of various fields,it is of great practical significance to develop new and efficient functional siloxane surfactants.The introduction of different hydrophilic groups to modify the polysiloxane has become one of the effective methods for the development of new functional surfactants.Butynediol-ethoxylate is a downstream product of coal chemical industry with rich sources and low foaming properties.The combination of butynediol-ethoxylate and siloxane surfactant could enhance some of properties of siloxane surfactants.In order to improve the physico-chemical properties of polysiloxanes modified by butynediol-ethoxylate,bola polysiloxanes modified with butynediol-ethoxylate were designed and synthesized in this paper.And the article explores synthesis conditions,physico-chemical properties and application properties.?1?Synthesis and process optimization.Firstly,under the condition of concentrated sulfuric acid as a catalyst,tetramethyl dihydrogen disiloxane as a capping agent reacted with octamethyl cyclotetrasiloxane by open ring reaction to obtain hydride terminated polysiloxane?HTP?with different degrees of polymerization.The degrees of polymerization of hydride terminated polysiloxane were analyzed by active hydrogen content determination method and ensured by¹H NMR again,and the degrees of polymerization of HTP were determined to be n=2,3,5,and 6.Then,the coal-based surfactant butynediol-ethoxylate?BEO?was used to modify HTP with chloroplatinic acid acts as a catalyst.The effect of reaction time,reaction temperature,catalyst concentration and feed ratio n?C?C?:n?Si-H?on the reaction was determined the conversion rate of HTP measured by the gas volume method.A series of bola polysiloxane surfactants modified by butynediol-ethoxylate?HBBP?were synthesized with optimal technological condition?the code name of HBBP were P2-4,P3-4,P5-4 and P6-4?.Finally,the structures of HBBP were confirmed by FT-IR,¹H NMR,²⁹Si NMR and ¹³C NMR.?2?Researches on physico-chemical properties.The equilibrium surface tension,dynamic adsorption performance,spreading wetting ability and aggregation behaviors of HBBP in aqueous solution were studied.HBBP own lower equilibrium surface tension,and the equilibrium surface tension of HBBP aqueous solutions could reach to about 25mN/m,and the CMC of HBBP were about 0.1×10^-33 mol/L.With the hydrophobic chain length increased from P2-4 to P6-4,the dynamic adsorption rate and the spreading wetting ability of HBBP gradually decreased.Finally,the aggregation behaviors of HBBP aqueous solutions were investigated by TEM and DLS.When the concentrations of HBBP were higher than CMC,the molecules will aggregate together to form spherical micelles by the strong hydrophobic interaction.?3?Application performance study.In this paper,foam properties of HBBP,FP and FPF aqueous solutions were measured by Ross foam apparatus.In terms of leveling properties and foam performance in coating with working viscosity,there were the comparisons of HBBP and polyether-modified silicones?FP,FPF,FC-7038?.The results indicate that HBBP have no foam,FP and FPF have low foam.The leveling properties of HBBP were basically the same as that of FC-7038,but the leveling properties of FP and FPF are slightly weaker in working viscosity coating.When the concentration of sample is 0.3 wt%,HBBP have lower foaming property than FC-7038,which may be suitable for leveling agent.