| The polymer/inorganic nanoparticle composite material contains inorganic particles and organic polymer chains,combines the advantages of inorganic nanoparticles in optics,electricity,magnetics,catalysis,biology,mechanics,etc.,as well as the solubility and chemical activity of the polymer,and processability advantages.Because of its unique properties,it has a good application prospect and gradually becomes a hot spot in the field of material research.Among them,the widely used inorganic nano-silica particles have significant small size and surface effects attracting the attention of many researchers at home and abroad.In this paper,nano silica particles were modified by grafting polymers and studied.The main contents are as follows:1.Using TDI as a coupling agent to modify nano-silica particles,and then reacting with 2-hydroxy-2'-ethyl-2'-bromopropionic acid ethyl ester to synthesize surface containing atom transfer radical polymerization.?ATRP?Initiator Nanosilica Particles?SiO2-Br?.It was characterized by 1H NMR,FTIR,TG and XPS.A 0.64 mmol/g nanoparticle initiator was successfully synthesized.Then the polyacrylamide?PAM?was grafted onto the surface of the nanosilica particles by ATRP method.The product was characterized by FTIR and GPC,indicating that the nano-SiO2/PAM composites were successfully synthesized.In addition,the dispersibility of nano-silica particles before and after modification in organic solvents was also compared,and it was found that the modified nanoparticles can be well dispersed in organic solvents,further confirming the successful synthesis of nano-SiO2/PAM composites.2.The silane coupling agent KH570 was used to modify the nano-silica particles.The optimum conditions of the coupling reaction were studied by orthogonal experiments.When the alcohol-water mixed solution was used as the solvent,the reaction temperature was 75 ?.10h is the best reaction condition.The grafted polymethyl methacrylate?PMMA?was grafted on the surface of the modified nano-silica particles by emulsion polymerization.The product was analyzed by FTIR and TGA.The results showed that the thermal stability of the synthesized nano-SiO2/PMMA was better than that of pure PMMA.With greater improvement,the thermal decomposition temperature of the composites increases by 38? when the content of nano-silica is 31.12%.3.Silica coupling agent KH550 and dibromoisobutyryl bromide were used to modify the surface of nano-silica particles.Nanosilica particles?SiO2-Br?containing ATRP initiator were synthesized.It was characterized by FTIR,TGA and XPS.The results showed that the grafting rate of the amidation method after the reaction of the nano-silica particles with the coupling agent was higher,and the 0.28 mmol/g nanoparticle initiator was successfully synthesized.SiO2-PMMA andSiO2-PMMA-g-PS composites were synthesized by ATRP.The products were characterized by TG and GPC,which showed that the synthesis of SiO2-PMMA and SiO2-PMMA-g-PS composite particles was successful.GPC analysis shows that the composite material has a predetermined structure of molecular design,and the polymerization reaction has the characteristics of controllable/active reaction. |
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