Synthesis And Superhydrophobic Properties Of Alkyl Multialkoxy Polysiloxane Emulsion

Organosilicone emulsion was widely used in the adhesive,waterproof coating,and other fields because of its special structure.In this paper,the study on variety,preparation and application of organosilicone emulsion was reviewed,and the application of organosilicone in hydrophobic material research was also introduced.The polymerization technology,property of alkyltrialkoxysilane polymerization emulsion and performance of latex film was investigated in details.The application of copolymerization emulsion by methyltriethoxysilane(MTEOS),n-propyltrimethoxysilane(PTMOS),y-(2,3 epoxypropyl oxygen)propyl trimethoxysiliane(EPTMS)and PDMS with hydroxyl in superhydrophobic coating was emphatically explored.The stable poly(alkyltrialkoxysiloxane)latex was synthesized via emulsion polymerization under alkaline conditions and compound emulsifier using PTMOS,MTEOS/PTMOS,n-octylmethoxysilane(OTMS)/PTMOS.The compound emulsifier was composed of sodium dodecylsulfate(SDS),sodium dodecylbenzesulfonate(SDBS)and Polyoxyethylene octylphenol ether(OP-10).The influence of different feeding modes(batch and semi-continuous),ratio of monomer,reaction temperature and time on emulsion particle size structure and properties was investigated;the model of the core-shell structure formation mechanism in emulsion polymerization was put forward.The polymer structure was characterized by FTIR;the particle size and structure were characterized by dynamic laser scattering(DLS),transmission electron microscopy(TEM),scanning electron microscopy(SEM);the thermal properties of polymer was carried out by Thermal gravimetric analysis(TGA);the hydrophobic performance of coating was characterized by the static contact angle tester;the polymer phase characteristics by X-ray diffraction(XRD).The results indicated that the particle sizes of poly(alkyltrialkoxysiloxane)emulsion increased and finally tended to be constant as with the extension of reaction time.The latex particle size distribution index(PDI)decreased as with the extension of reaction time.The particle size prepared by batch was larger than that by semi-continuous,while the PDI was smaller.The actual solid content of emulsion was 15.6%(by batch)and 15.5%(by semi-continuous)when monomers mass fraction was 30%in the total system.During the emulsion polymerization by semi-continuous,we found that the core-shell particles were formed during the chemical bonds reconstruction,shrinkage and rotation in the hydrolyzation and condensation reaction process;the particles had three change stages(nucleation period,growth period and stable period)during the emulsion polymerization;the shell of emulsion hybrid particles was organic layer(alkyl),and their core of those was inorganic layer(Si-O-Si-).The formation mechanism of core-shell structure was discussed.The latex could be stored more than 6 months,and the latex centrifugal stability was excellent.The polymerization coagulum content ranged between 0.09wt%and 0.31wt%.The weight percentages of poly(alkyltrialkoxysiloxane)are above 90%when the temperature is 400 ? in nitrogen atmosphere.There were some similar crystal structures in the molecular chain of polyalkylsilsequioxane prepared with alkyltrialkoxysilane.The hydrophobility of OTMOS/PTMOS(1:4)latex(WCA?110.8°)was much more durable than others for its long alkyl chain.The preparation of superhydrophobic coating can be obtained through control the coating surface morphology of organicsilicone emulsion which is a hydrophobic material.Based on the synthesis of polyalkylsilsequioxane emulsion,we firstly prepared a composite emulsion with PTMOS/SiO2 and PTMOS/SiO2/phenyltrimethoxysilane(PHTMOS).After comparison of hydrophobic effect among varieties of different composite emulsion,we fabricated a superhydrophobic surface by casting the alkoxy polysiloxane copolymerization composite emulsion containing fumes silica and PHTMOS/EPTMOS on the glass slide.The facile method is simple and low cost.The method offer an effective strategy and promising industrial applications for fabricating superhydrophobic surfaces.The hybrid quaternary copolymerization emulsion is prepared by alkaline-catalyzed co-hydrolysis and condensation reactions of MTEOS,PTMOS,PDMS and EPTMS.With increasing of fumes silica content,the contact angles first increased and then decreased,and the sliding angle first decreased and then increased.Under the content of fumes silica keeping constant,with the total of mixture silanes(PHTMOS:EPTMOS=1:2,mass ratio)increases,the contact angle has no significant change(contact angle 155°±2°),but sliding angle decreases obviously.When the content of fumes silica is 23wt%and the total content of PHTMOS and EPTMOS is 15wt%,the contact angle is 156.1° and sliding angle is 3°,and the thermostability of as-prepared surface coating is best.