| As a typical transparent polymer material,polymethyl methacrylate（PMMA）is also known as plexiglass or acrylic.It has good transparency but its poor flame retardancy greatly limits its application.In this paper,the nano flame retardant and synergistic flame retardant were used to prepare polymethyl methacrylate nanocomposites through melt blending method,which not only maintains the transparency of the material,but also enhances the flame retardancy.The main research content is as follows:（1）Grafting polymethyl methacrylate on the surface of SiO2（30nm）byγ-methacryloxypropyltrimethoxysilane（KH570）,then preparing PMMA/SiO2-g-PMMA composites.The synthesized PMMA/SiO2-g-PMMA were characterized by TGA and UV-vis,the results showed that SiO2-g-PMMA could enhance the thermal stability of PMMA and the light transmittance of the PMMA5SiO2-g-PMMA composite was 88.9%.（2）In order to improve the flame retardancy of PMMA.First DOPO-VTS was synthesized by the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide（DOPO）and vinyltrimethoxysilane（VTS）.Then,the surface of SiO2 was grafted with flame retardant DOPO.Finally PMMA/SiO2-g-DOPO composites were prepared.The flame ratardance properties of PMMA/SiO2-g-DOPO composites were evaluated by the cone calorimeter test（CCT）,results showed the peak heat release rate（PHRR）of PMMA10SiO2-g-DOPO composite was decreased by 52.2%.（3）The flame retardant triphenyl phosphate（TPP）or tris（2-chloropropyl）phosphate（TCPP）with the refractive index similar to PMMA were selected as synergists to prepare PMMA/SiO2-g-PMMA/TPP and PMMA/SiO2-g-PMMA/TCPP composites.The flame retardancy properties of the synthesized composites were estimated by limiting oxygen index（LOI）and vertical burning test（UL-94）,which suggests that the PMMA/SiO2-g-PMMA/TPP and PMMA/SiO2-g-PMMA/TCPP composites possess flame retardant rating. |
