Preparation And Performance For Self-Healing Insulation Film Based On LaB₆ Nanoparticles

Energy plays an important role in economic development.Energy conservation,environmental protection and sustainable development become the mainstream of social development in view of energy shortage.Building energy consumption in China's energy consumption structure is the largest proportion,and an effective way to reduce building energy consumption is to improve the insulation performance of existing building doors and windows.The excellent near-infrared absorption characteristics of lanthanum hexaboride?LaB₆?and the great change of near-infrared light absorption rate before and after VO₂ phase transformation had became the research hotspots of window insulation film,which can effectively improve the heat insulation performance of doors and windows.A self-healing thermal insulation film based on LaB₆ was investigated.In this paper,the required functional LaB₆ particles for the thermal barrier film were firstly prepared.LaCl₃ and NaBH₄ were used as reactants to synthesize LaB₆nanopowder under an Ar atmosphere at 400°C.XRD patterns and TEM images demonstrated that the prepared samples were mixture of LaB₆ crystals and amorphous boron oxide.The product size ranged from a few nanometers to several tens of nanometers.It can be seen from the TEM image that the surfaces of the product were coated with a layer of amorphous boron oxide.In order to investigate the effect of LaB₆ content and thickness on the properties of the thermal barrier film,LaB₆/PnBA-r-PMAUPy thermal insulation film was prepared by using 2-ureido-4[1H]-pyrimidinone?MAUPy?and butyl acrylate?nBA?as the reactants,azobisisobutyronitrile?AIBN?as initiator and N,N-dimethylformamide?DMF?as solvent at 70oC for 2 h via in-situ polymerization.The composition,self-healing effect,light transmittance and heat insulation rate of the thermal insulation films were characterized by XRD,tensile test,rheological test and light transmittance and heat insulation rate test.The results showed that the prepared membrane material had good self-healing performance and heat insulation efficiency,and the self-healing range is 88.0%-75.5%.The VO₂?M?functional particles were prepared by two-step method.The VO₂?D?was prepared by hydrothermal method using NH₄VO₃ and HCOOH as reactants at200°C for 48h.VO₂?D?was calcined at 400°C to obtain VO₂?M?.The prepared samples were characterized by XRD,TEM,and DSC.The characterization results showed that the prepared sample was VO₂?M?of regular star morphology,and the thermotropic phase transition property was consistent with those reported in the literature.The phase transition temperature was 67.97°C and the enthalpy value was31.2 J/g.In order to investigate the effect of VO₂ content on the properties of the thermal barrier film,LaB₆-VO₂/PnBA-r-PMAUPy thermal insulation film was prepared by in-situ polymerization whhile the thickness of the thermal barrier film was constant and the LaB₆ content was 5 mg.The composition,self-healing effect,light transmittance and heat insulation rate of the thermal insulation film were characterized by XRD,tensile test,rheological test and light transmittance and heat insulation rate test.The results showed that the prepared membrane material had good self-healing properties and heat insulation efficiency.