Study On The Preparation And Properties Of Surface Modified Nanoparticles/Polyurethane Composities

Polyurethane?PU?with high flexibility,wear resistance,low temperature,ozone resistance and many other excellent performance is widely used,But it aslo has strength,heat resistance,water resistance,solvent resistance and other defects,making it limited in certain areas of application.Inorganic materials have many characteristics for example high melting point,high hardness,good wear and oxidation resistance.We added a small amount of inorganic nanoparticles into polymer to prepare inorganic nanoparticles/polyurethane composite materials,the mechanical properties and thermal properties can be improved obviously.In this paper,the surface of nano-SiO₂,nano-CaCO₃ and CNT was modified with KH-550.The modified nanoparticles were characterized by infrared spectroscopy and contact angle test,indicating that there was a strong interaction between the nanoparticles and the coupling agent.We respectively prepared modified nano-SiO₂/polyurethane?SiO₂/PU?,nano-CaCO₃/polyurethane?CaCO₃/PU?and KCNT/polyurethane?KCNT/PU?by in-situ polymerization.Morphology,thermal performances and mechanical properties of the composites were investigated by infrared spectroscopy?IR?,scanning electron microscope?SEM?,thermogravimetric analysis?TGA?,water resistance test,universal testing machine and Ultra-high resistance tester.Study on the properties of modified SiO₂/PU composites,TGA data showed that thermal stability of polyurethane increased after adding surface-treated SiO₂.When the content of SiO₂ was 1 wt%,the decomposition temperature was the highest.T5 of SiO₂/MDI-based polyurethane was 320.46 ?,T5 of SiO₂/IPDI-based polyurethane was 315.74 ?.The mechanical test results showed that tensile strength improved with the increase of the content of SiO₂.When the content of SiO₂ was 1 wt%,the mechanical properties reached maximum.The tensile strength of SiO₂/MDI-based polyurethane increased 4.58 Mpa.The tensile strength of SiO₂/IPDI-based polyurethane increased 5.96 Mpa.Water absorption of the modified SiO₂/PU nanocomposites reduced with the increase of the content of SiO₂.Study on the properties of modified CaCO₃/PU composites,TGA data showed that thermal stability of polyurethane increased after adding CaCO₃.When the content of CaCO₃ was 1 wt%,the decomposition temperature was the highest.T5of CaCO₃/MDI-based polyurethane was 322.02 ?,T5 of CaCO₃/IPDI-based polyurethane was 319.80 ?.The mechanical test results showed that tensile strength improved with the increase of the content of CaCO₃.When the content of CaCO₃ was 1 wt%,the mechanical properties reached maximum.The tensile strength of CaCO₃/MDI-based polyurethane increased 5.89 Mpa.the tensile strength of CaCO₃/IPDI-based polyurethane increased 7.54 Mpa.Water absorption of the modified CaCO₃/PU nanocomposites reduced with the increase of the content of CaCO₃.Study on the properties of KCNT/PU composites,TGA data showed that thermal stability of polyurethane increased after adding KCNT.When the content of KCNT.was 0.75 wt%,the decomposition temperature was the highest.T5of KCNT/MDI-based polyurethane was 319.31 ?,T5of KCNT/IPDI-based polyurethane was 316.39 ?.The mechanical test results showed that tensile strength improved with the increase of the content of KCNT When the content of KCNT was 0.75 wt%,the mechanical properties reached maximum.The tensile strength of KCNT/MDI-based polyurethane increased 2.65 Mpa.The tensile strength KCNT/IPDI-based polyurethane increased 3.55 Mpa.Conductivity of the modified KCNT/PU nanocomposites improved with the content of KCNT increased.Different inorganic fillers have an enhanced effect on the polyurethane,SiO₂/PU composite material has the best toughening and water resistance.CaCO₃/PU has better hardness,tensile strength and heat resistance.KCNT/PU have conductivity.