Synthesis Of Organic Fluorine Compounds And Study Of Organic Fluorine/Silicon Modified Waterborne Polyurethane

Taking the advantages of safety,environmental friendly,good film-forming performance,excellent physical properties,waterborne polyurethanes(WPU)have been widely applied in coatings,adhesives,fabric coatings,elastomer materials,fibers,biomaterials and so on.However,the water-resistance of WPU is always poor due to the presence of hydrophilic substances or groups in their macromolecules.Polysiloxane has low surface energy,excellent water resistance,high thermal stability,low glass transition temperature.Fluorine-containing organic compounds have low surface energy,high thermal stability,excellent water resistance,chemical inactivity,and so on.Introduction of organic fluorine and/or silicon chains into the WPU can combine the respective advantages of them to improve the deficiency of the WPU.Currently,there are few types of fluorochemicals for the purposes of WPU modification.Based on these issues,a series of fluorinated organic compounds terminated with amine or hydroxyl groups were prepared.Then,the fluorinated and/or silicone compounds have been used as extending chains to introduce into the WPU macromolecules.The effect of fluorinated and/or silicone compounds on the properties of WPU was investigated.The main contents are as follows:1.A secondary amine-and hydroxyl-terminated fluorochemicals including DFMA-IPDA,FBMA-DEA and DFMA-DEA were synthesized via Michael addition reaction by hexafluorobutyl methacrylate(FBMA),dodecafluoroheptyl methacrylate(DFMA),isophorone diamine(IPDA)and diethanolamine(DEA),respectively.FT-IR,~1H-NMR and GPC characterizations showed that the fluorinated compounds were successfully synthesized according to the experimental design and their purities were higher than 98%.2.A series of fluorine-modified WPU with different chains length and amount of fluorocarbon were prepared by replacing 1,4-butanediol(BDO)with FBMA-DEA and DFMA-DEA partially or totally to investigate the effect of fluorocarbon on the properties of WPU emulsions and films.The results showed that the average particle size of WPU emulsion increased with increasing the chain length or the amount of fluorocarbon.Meanwhile,the tensile strength,thermal stability,water resistance and surface hydrophobicity of the films were also greatly improved,but the elongation at break decreased.Compared to the film of unmodified WPU,the film of DFMA-DEA modified WPU showed tensile strength increased from 10.1 MPa to 14.5 MPa,the water absorption decreased from 18.0%to 6.5%and the water contact angle increased from 71.4°to 93.9°,respectively.3.Fluorine-silicon co-modified WPU were synthesized by using polyoxypropylene glycol(PPG)and polydimethylsiloxane(PDMS)as mixed soft segments,and partial or total fluorine-containing DFMA-IPDA.The effect of fluorine and silicon content on the properties of the emulsion and the properties of the film were investigated.An increase in the content of PDMS and/or DFMA-IPDA led to an increase in the average particle size of WPU emulsions,and thermal stability,water resistance,surface water contact angle of the WPU films.PDMS can improve the flexibility of WPU film,whereas DFMA-IPDA can increase their toughness.When the chain extender was completely replaced with DFMA-IPDA,the water absorption of the WPU film was 4.5%,and the water contact angle reached 102.3°as the amount of PDMS was 4%.