Microstructure and Optical Properties of PMMA Matrix Composites Containing LaB₆ Nanoparticles

摘要

he lanthanum hexaboride (LaB₆) nanoparticles are synthesized via a solidudstate reaction in vacuum. Silane coupling agent is used for modifying theudsurface of the nanoparticles. This process is carried out in different solutionsudso as to ascertain the best modification technology. Modified LaB₆ nanoparticlesudare added to polymethyl methacrylate (PMMA) matrix by in-situ polymerization.udSynthesized nanoparticles are characterized by XRD and TEM, theudresults show that the obtained particles have high degree of crystallinity andudelliptical or cubic shape, the size ranged from 20 nm to 100 nm. In addition,udFESEM and Medium infra-red spectrometers are used to prove the effect ofudsurface modification of nanoparticles, alcohol solution can provide the bestudmodification atmosphere for the modifying process, as LaB₆ nanoparticlesudmodified in alcohol solution appear in uniformly elliptic shape and smallestudsize. Furthermore, the microstructure of PMMA/LaB₆ composites are characterized,udand optical properties of the composites are tested by UV-vis-NIRudspectrophotometry. Experimental results show that modified LaB₆ nanoparticlesuddispersed well in the PMMA matrix, the relationship between addedudLaB₆ nanoparticles and optical properties of PMMA matrix is demonstratedudas well. PMMA matrix contained 0.02% wt. LaB₆ nanoparticles can blockudNIR effectively with slight influence on the high transparency of PMMA matrix.