Preparation Of Ag-Ga/PMMA Nano-composite Materials By Ultrasonic

Ultrasonic radiation method without any initiator or metal reducer was used to prepare nanometer Ag-Ga alloy formed by silver cluster with gallium atoms; synchronously, polymethyl methacrylate is synthesized by ultrasonic radiation in-situ MMA emulsion polymerization, which enwrapped alloy nano-particles; thus, Ag-Ga/PMMA nano-composite materials were obtained and characterized by means of HREM, XRD and XPS and so on.Emulsion polymerization of methyl methacrylate without any initiator was investigated. Experimental results showed that the reaction conditions were optimized: ultrasonic power 400W, ultrasonic time 45 min, content of emulsifier 0.5wt%, content of metal 0.3 wt%, velocity of flow of N₂ 80ml/min, and reaction temperature 45±2℃.HREM with EDS indicated that the nano-composite particles presented core-shell structure with diameters of 80～200nm, as well as excellent monodispersity, and the core with dark color was of metal, the shell with light color was of PMMA. The phenomenon of the shell of the particles via layer-by-layer PMMA self-assembly is found, the distance between layers was calculated to be about 2.8nm.XRD proved that the synthesis of alloy Ag_0.72Ga_0.28 and the probability of new Ag-Ga alloy because of two unknown diffraction peaks in XRD spectrum.The microstructure of Ag-Ga alloy/PMMA nano-composite materials were characterized by FT-IR and XPS. The experimental results showed that the combination between metal particle and PMMA was not only physical action, but also certain of chemical action. Thereby, the nano-composite materials were obtained.The thermo analysis of Ag-Ga alloy/PMMA nano-composite materials was tested by TG-DSC. The results indicated that the T_g(85℃) was lower than the pure PMMA's(104℃), and the decomposition temperature(380℃) was higher than the pure PMMA's.