Construction Of Fluoro-Silicon Modifed Polyurea Coatings

Along with the increasing attention to environmental protection,polyurea（PU）has attracted more and more people’s attention because of its excellent green environmental characteristics.However,traditional polyurea materials have shortcomings such as fast reaction speed,poor adhesion and poor water resistance,etc.Which limit its further application,therefore,the modification of polyurea coatings was studied in this paper.1,3-bis（3-aminopropyl）tetramethyldisiloxane（APTMDS）and diethyl maleate（DM）were selected to synthesize silane polyaspartate（DM-APTMDS）by Michael addition.Using DM-APTMDS as modifier and introducing different amounts of DM-APTMDS into amine components to prepare DM-APTMDS modified polyurea coatings.By analyzing the static water contact angle（WCA）,thermogravimetric analysis（TG）,adhesion,anticorrosion,mechanical and other properties.The results showed that when the mass fraction of DM-APTMDS in the amine component was about 21%,and comprehensive performance of Si PU-21 was the best,the water contact angle was enhanced by 27.44%from 78.0°to 99.4°.Then,the initial thermal decomposition temperature(T_5%)increased from 210.7℃to 221.0℃,the adhesion of the coating increased from 6.98±0.90 MPa to 8.49±0.64 MPa by 21.63%.Meanwhile,the tafel polarization curve and salt spray resistance tested,the results showed that the corrosive area of Si PU-21 coating surface was minimal after 7 days of salt spray corrosion,and the corrosion current density was reduced to 7.21×10^-8 A·cm^-2.The experiments on anticorrosion showed that the coating had excellent good ability of anticorrosion.By utilizing the good adhesion of polydopamine（PDA）and was used as a modifier,then,introducing different amounts of PDA into amine components to strengthen the binding between DM-APTMDS and PU.Meanwhile,PDA modified Si PU coatings were prepared.Through the performance analysis of the static water contact angle（WCA）,thermogravimetric analysis（TG）,adhesion,anticorrosion,mechanical and other properties.The results showed that when the mass fraction of PDA in the amine component was about 0.7%,and comprehensive performance of 0.7%PDA-Si PU was the best.Compared with Si PU film,the initial thermal decomposition temperature(T_5%)has no significant change.The coating adhesion was increased from 8.49±0.64 MPa to 9.75±0.13 MPa,which increased by 39.68%and 14.84%compare to PU and Si PU,respectively.The mechanical properties of PDA-Si PU films with 10d ultraviolet（UV）aging resistance were significantly improved,then,the elongation at break retention rate was enhanced to 86.32%,which was16.33%and 8.77%higher than that of PU and Si PU films after UV aging.Meanwhile,the salt spray resistance and tafel polarization curve tested,the results showed that the corrosive area of 0.7%PDA-Si PU coating surface was minimal after 7 days of salt spray corrosion,and low corrosion current density.The experiments on anticorrosion showed that the coating had excellent good ability of anticorrosion.Finally,hexafluorobutyl methacrylate（HFMA）and APTMDS were selected to synthesize fluorosilane（HFMA-APTMDS）by Michael addition.Using HFMA-APTMDS as a modifier and introducing different mass fractions of HFMA-APTMDS into amine components to prepare modified polyurea coatings.By analyzing the static water contact angle（WCA）,thermogravimetric analysis（TG）,adhesion,anticorrosion,mechanical and other properties.The results showed that when the mass fraction of HFMA-APTMDS in amine component was about 20%,and comprehensive performance of FSi PU-20 was the best,the initial thermal decomposition temperature(T_5%)increased by 19.76%from 210.7℃to252.4℃.The water contact angle was increased from 78.0°to 99.7°,and the coating adhesion was increased from 6.98±0.90MPa to 8.23±0.33MPa,an increasing of 17.91%.After immersing in N,N-dimethylformamide solvent for 24 h,the mass change rate decreased from 54.84%to 24.90%.Meanwhile,the tafel polarization curve and salt spray resistance tested,the results showed that the corrosive area of FSi PU-20 coating surface was minimal after 7 days of salt spray corrosion,and the corrosion current density was reduced to 1.15×10^-8 A·cm^-2.The experiments on anticorrosion showed that the coating had excellent good ability of anticorrosion.