Reinforced sound insulation properties of styrene-acrylonitrile copolymer composites via using organo-montmorillonite loaded polymethylmethacrylate microspheres

Abstract

Sound insulation material has been broadly used in transportation or construction industries to control noise. Polymer composites have been used in acoustic areas due to their low density and feasible processing capability. In this work, organo-montmorillonite (OMMT) lamellae were adsorbed onto polymethyl methacrylate (PMMA) microspheres via soap-free emulsion polymerization to obtain PMMA@OMMT composite microspheres on reinforcing the sound-insulating effect of styrene-acrylonitrile copolymer (SAN). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the successful loading of OMMT on PMMA microspheres. The sound insulation properties of SAN by incorporating PMMA@OMMT were conducted using a four-microphone impedance tube. The results revealed that PMMA@OMMT composite microspheres were more efficient in enhancing the sound insulation properties of SAN than that using simple blending commercial pelletized PMMA with OMMT or PMMA microspheres with MMT. The average sound transmission loss (STL) of SAN/PMMA@OMMT (5 wt%) composites could reach 38.97 dB, which exceeded previous reports by taking into consideration the thin thickness and few filler loadings. The sound reinforcing mechanism for PMMA@OMMT on SAN was analyzed using dynamic mechanical analysis. This work will broaden the application of OMMT in sound insulation and provide a novel solution for designing lightweight sound-insulation materials.