Study On Preparation Of Nanocomposites And Surface Modification Of Nano-CaCO₃

The nanometer calcium carbonate was the calcium carbonate nanoparticles by the chemical synthesis, which diameter was less than 100nm,and was a new ultra-fine solid material.In this paper, the problems of the shape-controllable synthesis and surface modification and applications that were closely related to issues of the CaC03 nanoparticles were studied. Firstly using the way of low-temperature carbonization, the different morphological of nano-CaCO3 were prepared, the controllable synthesis of technological conditions was studied, the surface of the prepared nano-calcium carbonate was modified, meanwhile the late-model compound modifier was researched and developmented. Based on the above work, the core/shell composite particles were prepared, and the PMMA/CaC03 of nanocomposite was prepared, the mechanical property of nanocomposites was studied.The main research results as following:(1)The industrial of CaO was used as raw materials, using the way of low-temperature carbonization, the controlled spherical nano-calcium carbonate particles were prepared, they were discussed that the influence of carbonization temperatures and the amount of crystal directing-agent on the size and topography of the prepared nano-CaCO3.The structure and morphology of the product were characterized by XRD and TEM, the calcium carbonate has particle size distribution, uniform particle size and good dispersibility when the reacting conditions were the best. Under the same experimental condition, the amount of crystal directing-agent the different morphological forms of nano-CaCO3 were prepared by changing the amount and species of crystal directing-agent.(2)To the spherical nano-calcium carbonate for the study, the surface of the nano-calcium carbonate was modified with KH-570 and sodium stearate as compound modifier, the prepared samples are investigated by the oil absorption number,FT-IR and TEM,the compound modifier and optimal proportion were selected.the modified nano-calcium carbonate have the low of oil absorption value、the high of activation grade、the good of dispersibility.The other late-model compound modifier were researched and developmented.(3)Firstly in this paper, the superfine CaCO3 was disposed by KH-570,then the nanocomposite particles with core (nano inorganic particles)-shell (PMMA) were prepared by emulsifier-free polymerization. The effects of many factors such as amount of inorganic nanoparticles, MMA, initiator and temperature on emulsifier free polymerization were investigated.The structure and the mechanism of the nanocomposite particle were analyzed though XRD,TGand TEM.(4)The surface of the nano-calcium carbonate was modified with KH-570, the PMMA/CaCO3 nanocomposites were prepared by in situ polymerization.The interfacial compatibility between nano-CaCO3 and PMMA matrix was characterized by dissolution,SEM and FT-IR,the mechanical property of nanocomposites was studied.