Preparation And Heat Resistance Mechanism Of Nd₂O₃/TPUnanocomposites

In this study,the thermal stability,mechanical properties and surface properties of thermoplastic polyurethane elastomers were greatly improved by replacing traditional non-covalent bonds such as hydrogen bonding with covalent bonds formed by polar groups of thermoplastic polyurethane elastomers and neodymium oxide nanoparticles with high activity and easy coordination.Furthermore,the microphase separation of TPU/Nd₂O₃ nanocomposites was qualitatively and quantitatively characterized,and the mechanism of Nd₂O₃ nanoparticles on the microphase separation and properties of TPU was also investigated.The main research results are as follows:?1?Nd₂O₃ nanoparticles were successfully prepared via ultrasonic-spray-assisted hydrothermal method.The results showed that the prepared Nd₂O₃ nanoparticles were monodisperse,cubic fluorite structure with a diameter of 40 nm.And the surface energy of Nd₂O₃ nanoparticles was 125.39 m²/g.In addition,the synthesis process of Nd₂O₃nanoparticles was also studied.It was found that the surfactant type,reaction time and calcination temperature had a great influence on the morphology and structure of Nd₂O₃nanoparticles.?2?The thermoplastic polyurethane/Nd₂O₃?Nd₂O₃/TPU?nanocomposites with different content of Nd₂O₃ nanoparticles were synthesized via an in-situ bulk polymerization technique.The degree of microphase separation of TPU nanocomposites was quantitative calculated by FTIR and DMA.The introduction of Nd₂O₃ nanoparticles can effectively improve the microphase separation of TPU.Based on this,a microphase separation model was constructed.Furthermore,the thermal properties of TPU nanocomposites were studied by DSC,DMA,VST,and TGA.The results showed that Nd₂O₃ nanoparticles adding can effectively improve the thermal properties of TPU.When the content of Nd₂O₃ nanoparticles was 0.5 wt%,compared with pure TPU,the melting temperature,thermal decomposition temperature,and Vicat softening temperature of TPU nanocomposites increased by 29.8°C,33.7°C,and 39.1°C,respectively.Meanwhile,the Nd₂O₃/TPU nanocomposites also illustrated better mechanical properties,surface properties,and chemical resistance characteristics,compared with pure TPU.?3?Finally,the interaction mechanism between Nd₂O₃ and TPU was investigated by X-ray Photoelectron Spectroscopy,which confirmed that the coordination bonds between Nd₂O₃ and carbamate groups of TPU were existed in the nanocomposites.Based on the change of binding energy of each element of Nd₂O₃ nanoparticles,TPU,and Nd₂O₃/TPU nanocomposites,it was found that the binding energy of Nd,N and O elements was consistent with the trend of microphase separation of TPU nanocomposites.Therefore,we believed that the effect of Nd₂O₃nanoparticles on TPU performance mainly followed the law of coordination bond-microphase separation-performance.