Research On The Preparation And Properties Of Organosilicone/halloysite Modified Waterborn Polyurethane

The introduction of hydrophilic groups during the synthesis of WPU with self-emulsification method results in side effect to the water resistance of WPU,which limited its use range.Organosilicone has a strong hydrophobic,good heat resistance and excellent surface properties,can improve some performance of WPU.DMPA and AAS-Na were used as mixed hydrophilic chain extender to prepare stable WPU emulsion with water as the dispersion medium.Effect of R value,the content of hydrophilic chain extender,the content of DMPA in hydrophilic chain extender,neutralization degree on the properties of emulsion particle size and storage stability.The stable polyurethane emulsion can be prepared when the R value is 1.2,the content of the hydrophilic chain extender is 4wt%,the DMPA accounts for 40% of the total amount of the hydrophilic chain extender and the neutralization degree is 0.9.FTIR indicating that DMPA and AAS-Na were successfully accessed into the polyurethane backbone.The Si-WPU were prepared by semi-continuous feeding method with PDMS-OH,butyl acetate and acetone(Volume ratio of 1: 1)as solvent.With the increase of the PDMS-OH content,the water absorption capacity of the coating was decreased and the water resistance was enhanced.The tensile strength of the coating decreased with the increase of the molecular weight of the polyether and the tensile strength of the coating film is on the rise when the content of PDMS-OH is within 9%.The elongation at break of the modified polyurethane coating film begins to decrease when the content of PDMS-OH is less than 9%.SEM test showed that the soft segment and the hard segment penetrated each other,and the hard segment played the role of physical cross-linking point and increased the mechanical properties of the polyurethane.The TEM test showed that the emulsion particles were spherical and the particle size was wide.The TG test showed that the polysilicon The introduction of oxygen,can improve the heat resistance of polyurethane.The HNTs/Si-WPU were prepared by physical blending method and the addition ofHNTs can make up for reduced tensile strength caused by organic silicon in WPU.HNTs has a good dispersion state when addited with IPDI?HDI?catalyst at the initial stage of thereaction.When the amount of HNTs is 1.5%,the tensile strength of the coating is 8.5MPa.When the amount of HNTs is 1%,the HNTs/Si-WPU elongation at break is 749%.TG and DSC test showed that the addition of HNTs can improve the thermal properties of Si-WPU.TEM and SEM indecated that HNTs has a large aspect ratio and hollow tubular structure can enhance the mechanical properties of the polymer when dispersed in the polyurethane matrix.