Synthesis And Characterization Of Fluoroalkyl-terminated Hyperbranched Polyurethane Film Forming Agent

In view of the shortcomings of poor water resistance of waterborne polyurethane,this paper has done the related modification research,the main research contents are listed as follows:Firstly,polyurethane prepolymer(PU)was prepared via the acetone process using isophorone diisocyanate(IPDI),polybutylene adipate(CMA-1044),1,4-butanediol(BDO)and dimethylolpropionic acid(DMPA)as raw materials.Hyperbranched polyurethane(HBPU)was synthesized through modification of PU by hydroxyl-terminated hyperbranched polymer.Then,novel fluoroalkyl-terminated hyperbranched polyurethane(HBPUF)was prepared by the grafting reaction of perfluorohexyl ethyl alcohol and HBPU.Finally,HBPUF emulsion was obtained by neutralization,adding water,and high-speed stirring operations.Fourier transform infrared spectrum(FT-IR),proton nuclear magnetic resonance spectrum(NMR),Transmission Electron Microscope(TEM),nano particle size,thermogravimetry analyzer(TGA),differential scanning calorimeter(DSC),x-ray diffractometer(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscope(SEM),atomic force microscope(AFM)and static contact angle analyzer were utilized to characterize structure of the resultants,particle morphology and average size,thermal properties,crystal structure,chemical compositions,morphology,hydrophobicity of the latex films,as well as the relative performance properties of the treated crust leather.FT-IR,1H NMR and 13 C NMR results confirmed that the final product had due structure.HBPUF latex possessed a favorable stability and the core-shell and regularly spherical pattern,where a faint,light and dark diffraction ring existed in the relatively bright inner region and this illustrated that the HBPUF polymer had some crystallinity.The fluoroalkyl groups had the tendency to enrich at the film-air interface during the film formation process by XPS,which engendered water contact angle on HBPUF film increase by 36.1°and water absorption of HBPUF film reduce by 125.2% compared to PU film.Thermal stabilities of PU,HBPU and HBPUF films were gradually enhanced by TGA analyses.DSC analyses revealed that the crystal-melting peaks all appeared in PU,HBPU and HBPUF and this denoted that crystallization should exist to some extent in the above polymers.XRD analyses further demonstrated that crystallinity did appear in PU,HBPU and HBPUF polymers.Furthermore,as a result of the incorporation of hyperbranched polymer,fine crystal particles emerged in the HBPU and HBPUF crystalline domain compared to PU and this phenomenon was also proved by SEM observation.AFM analyses indicated that PU film displayed the micro-phase separation pattern.Since the hyperbranched polymer has been imported into one end tail of the PU,curling or spirals amongst molecular chains should be impeded to some extent as a result of crosslinked action to make fine micro-morphology of HBPU film more flat.However,while the fluoroalkyl groups were grafted onto another end tail of the PU to form the HBPUF skeletons,owing to the significant surface enrichment of the terminal fluoroalkyl,HBPUF film presented much more micro-phase separated model with a greatly enhanced surface roughness.Secondly,polyurethane prepolymer(CPU)was obtained via the acetone process using isophorone diisocyanate(IPDI),polybutylene adipate(CMA-1044),1,4-butanediol(BDO)and n-methyl diethanolamine(MDEA)as raw materials.Hyperbranched polyurethane(CHBPU)was manufactured through modification of CPU by hydroxyl-terminated hyperbranched polymer.Then,novel fluoroalkyl-terminated hyperbranched polyurethane(CHBPUF)was prepared by the grafting reaction of perfluorohexyl ethyl alcohol and CHBPU.Finally,CHBPUF emulsion was obtained by neutralization,adding water,and high-speed stirring operations.Fourier transform infrared spectrum(FT-IR),proton nuclear magnetic resonance spectrum(NMR),Transmission Electron Microscope(TEM),nano particle size,thermogravimetry analyzer(TGA),differential scanning calorimeter(DSC),x-ray diffractometer(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscope(SEM),atomic force microscope(AFM)and static contact angle analyzer were used to characterize structure of the resultants,particle morphology and average size,thermal properties,crystal structure,chemical compositions,morphology,hydrophobicity of the latex films,as well as the relative performance properties of the treated crust leather.FT-IR,1H NMR and 13 C NMR results confirmed thatthe final product had due structure.CHBPUF latex had an unfavorable stability due to poor emulsifying capacity of the MDEA and the cream yellow appearance.The fluoroalkyl groups had the tendency to enrich at the film-air interface during the film formation process by XPS,which engendered water contact angle on CHBPUF film increase by 18.5° and water absorption of CHBPUF film reduce by 91.67% compared to CPU film.Thermal stabilities of CPU,CHBPU and CHBPUF films were gradually improved by TGA analyses.DSC analyses revealed that the crystal-melting peaks all appeared in CPU,CHBPU and CHBPUF and this denoted that crystallization should exist to some extent in the above polymers.XRD analyses further demonstrated that crystallinity did appear in CPU,CHBPU and CHBPUF polymers.Furthermore,as a result of the incorporation of hyperbranched polymer,fine crystal particles emerged in the CHBPU and CHBPUF crystalline domain compared to CPU and this phenomenon was also proved by SEM observation.AFM analyses indicated that CPU film displayed the micro-phase separation pattern.Since the hyperbranched polymer has been imported into one end tail of the CPU,curling or spirals amongst molecular chains should be impeded to some extent as a result of crosslinked action to make fine micro-morphology of CHBPU film more flat.However,while the fluoroalkyl groups were grafted onto another end tail of the CPU to form the CHBPUF skeletons,owing to the significant surface enrichment of the terminal fluoroalkyl,CHBPUF film presented much more micro-phase separated model with a greatly enhanced surface roughness.