Investigation On Synthesis Of A Novel Methylphenyl Silicone Resin And Flame Retardancy In Polycarbonate

Polymeric materials are a vital important part of today’s live, they can be found nearly everywhere. However, most polymeric materials are easy to burn to produce corrosive gases and toxic fumes caused a great threat to the safety of people’s lives. Using of flame retardants to reduce combustibility of the polymeric materials. Because of the environmental problems, The EC proposed to restrict the use of halogen-containing flame retardants that have high flame-resistant efficiency. Consequently, it is essential that new flame retardant systems should be developed to become the focus of the currently flame retardants development. Recently, silicon resin used as a kind of efficient and environment-friendly flame retardants have received more and more attentions.Polycarbonate (PC), has a high heat resistance, mechanical properties, transparency and excellent electrical properties. It was widely used in electrical and electronics, construction, transportation, medical equipment, optical equipment, aerospace and other fields. Because PC is a naturally high charring polymer, for the flame retardant properties of PC, it shows a limiting oxygen index (LOI) of approximate28%and a V-2rating in the UL-94test. However, strict flame retardant performance is often required for electronic and electric applications.In this paper, a rounded spherical nano-silicone resin flame retardant, Polymethylphenyl MQ silicone resin (PMPMQSR) was synthesized successfully by hydrolysis condensation reaction under acidic conditions from tetraethoxysilane, hexamethyldisiloxane and1,3-diphenyl-1,1,3,3-tetramethyldisiloxane. The structure was characterized by Fourier transform infrared spectroscopy (FTIR),1H nuclear magnetic resonance (’H-NMR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Transmission electron microscopy (TEM). The wettibility and thermal stability of PMPMQSR were investigated by static contact angle and thermogravimetric analysis, respectively. CA and TGA results demonstrated that PMPMQSR showed a good hydrophobic property with a water contact angle of145°. PMPMQSR showed a good thermal stability and a high of char-forming ability. In nitrogen and air, its initial decomposition temperature was362℃and340℃based on1wt%mass loss, and residu was84.1wt%and80.8wt%at800℃, respectively.PMPMQSR and anti-dripping were blended with Polycarbonate. The limiting oxygen index (LOI), UL-94test and mechanical properties were used to evaluate the properties of the composites. The results showed that flame retardant could effectively enhance flame retardancy of PC, however, mechanical properties slightly decreased.Thermal degradation behavior and combustion behavior of the FR-PC composites were measured by thermogracimetric analysis (TGA) and cone calorimeter (CONE), while morphological structures and elemental analysis of char layer were measured by X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM). TGA results demonstrated that the addition of PMPMQSR promoted the PC crosslinked degradation and improve the high thermal stability of PC. CONE test results demonstrated that PMPMQSR could effectively decrease the heat release rate (HRR) and the total heat release (THR) of PC. XPS and SEM test results revealed that the polysiloxane unique-Si-O-inorganic protective layer of the char layer formed on the surface to effectively improve the flame retardancy of the material.