Study On Preparation And Properties Of Waterborne Polyurethane/Fe₃O₄ Nanocomposite

In this paper, waterborne polyurethane/Fe₃O₄ nanocomposite with magnetic properties was studied. This paper divided into three parts. The first part is about preparation and characterization of nano-Fe₃O₄ magnetic particles modified by silane. The second part is related to the preparation and properties of waterborne sulfhate polyurethane/Fe₃O₄. In the third part, UV-curable waterborne polyurethane/Fe₃O₄ was synthesizd. All the relative studies are outline as follows:（1） The nano-Fe₃O₄ particles were modified with KH550 using the ultrasonic vibration and mechanical agitation. The N-H (1550cm^-1) in the FTIR spectra of KH550-Fe₃O₄, elementalanalysis of N%, and XRD analysis confirm chemisorptions of KH550 onto the Fe₃O₄ nanoparticles surface. The SEM indicates the size of KH550-Fe₃O₄ was slightly increased, the VSM results showed that the magnetic saturation of KH550-Fe₃O₄（43emu/g） was lower than the unmodified Fe₃O₄.（2） Waterborne sulfnate polyurethane/Fe₃O₄（WPU/Fe₃O₄） nanocomposites were prepared by IPDI, with BY3301, DASS and unmodified Fe₃O₄,which the Fe₃O₄ nanoparticles were doped into polyurethane directly. The FTIR spectra of WPU/Fe₃O₄ showed there there was no chemical bond betweenFe₃O₄ and WPU matrix. The XRD of WPU/Fe₃O₄ indicated that the crystal structure of Fe₃O₄ nanoparticles didn’t change. TG showed nanocomposites were more thermo-stable as compared to the organic polymers. DMA showed that the storage modulus of nanocomposites were higher than Waterborne sulfnate polyurethane, the storage modulus of nanocomposites was increased from 0.7Mpa to 1.08Mpa. SEM and AFM showed that there was some aggregation phenomenon when the the amount of Fe₃O₄nanoparticles was more than 3%. VSM showed that the WPU/Fe₃O₄ nanocomposites were magnetic composites, the magnetic saturation of nanocomposites were increased from 5.6emu/g to 25.6emu/g, because the magnetic anisotropy parameter of Fe₃O₄ was affected by the polyurethane, the magnetic saturation of nanocomposites were lower than the Fe₃O₄（3） Waterborne sulfnate polyurethane/KH550-Fe₃O₄（WPU/KH550-Fe₃O₄） nanocomposites were prepared by replacing Fe₃O₄ with KH550-Fe₃O₄. In this process, the KH550-Fe₃O₄ was incorporated into waterborne sulfnate polyurethane matrix using polymerization method. The FTIR spectra of WPU/KH550-Fe₃O₄ showed N-H peak at 3300 cm^-1 became broader, there there was chemical bond between KH550-Fe₃O₄ and WPU matrix. TG showed nanocomposites were more thermo-stable. The results of mechanical property of specimens showed that with the increasing content of KH550-Fe₃O₄nanoparticles, the tensile strength increases from 0.7 to 2.2 MPa. SEM indicated when the amount of KH550-Fe₃O₄ was 2%, the dispersion of nanoparticles and the compatibility between the inorganic particles and organic polymers is good. VSM indicated that the magnetic saturation of magnetic nanocomposites were increased with increasing content of KH550-Fe₃O₄.（4）UV-curable waterborne polyurethane/Fe₃O₄ nanocomposites were prepared by IPDI, with PCL, DMBA, castor oil, DBTDL, PETA,TEA and unmodified Fe₃O₄ by using situ polymerization method. The FTIR spectra of GPU/Fe₃O₄ showed there there was no chemical bond betweenFe₃O₄ and GPU matrix. TG showed thermal properties of the nanocomposites were improved. nanocomposites possess goodmechanical properties. The tensile strength of the composite film,in which the amount of Fe304nanocomposites was2%, was 13.46Mpa. VSM curves showed that the magnetic saturation of magnetic nanocomposites from 3.3emu/g to 14.8emu/g with increasing content of Fe₃O₄, which was lower than the magnetic saturation of Fe₃O₄. The smaller saturation magnetization value was due to the existence of UV-curable waterborne polyurethane.（5） UV-curable waterborne polyurethane/KH550-Fe₃O₄（GPU/KH550-Fe₃O₄） nanocomposites were prepared by replacing Fe₃O₄ with KH550-Fe₃O₄. The FTIR spectra of GPU/KH550-Fe₃O₄ showed there there was chemical bond between KH550-Fe₃O₄ and GPU matrix. TG showed thermal properties of the nanocomposites were improved, the initial decomposition temperature of composites were from 157 to 228 ℃. The tensile strength of composites were obviously improved from 9.6 to 27.37MPa. VSM curves showed that the magnetic saturation of magnetic nanocomposites from 1.5 to 4.8emu/g with increasing content of KH550-Fe₃O₄, which was lower than the magnetic saturation of KH550-Fe₃O₄.