Toughening And Flame Retardant Modification Of Silica Aerogel

Silica aerogel is a porous material with a three-dimensional spatial network structure.It has the characteristics of extremely low density,large specific surface area,high porosity,and extremely low thermal conductivity.It is widely used in adsorption,Catalysis,thermal insulation,medical treatment and other fields.However,ordinary silica aerogel has the disadvantages of being flammable,brittle,and low in strength,which severely limits the popularization and application of aerogel.Therefore,how to prepare an aerogel with high mechanical properties and improve its flame retardant performance has important practical significance.This article is based on the Si O₂aerogel prepared with dual precursors?MTMS and MDMDS?as the silicon source,first by adding the content of Xg?X=0.5wt%,1wt%,1.5wt%,2wt%,2.5wt%?Polyester fiber,improve the mechanical properties of the gel and characterize and analyze the toughened and modified aerogel;follow-up further by adding different flame retardants and changing the content of the flame retardant,explored its flame retardant modified flame retardant efffect of aerogel.The aerogel was characterized by density,shrinkage,compressive strength,and FI-IR,SEM,XRD and other methods.The results showed that the mechanical properties of the composite aerogel with 1.5 wt%polyester fiber content were the best Reached 200k Pa.The macropores of the gel are mainly distributed in the range of 6-18?m,the maximum value is about 9?m,the total invasion volume of the aerogel is about 5.65cm³/g;the thermal conductivity of the gel after toughening is 0.03872W/?m·K?;The waste oil adsorption rate of the toughened aerogel increases first and then decreases with the increase in the amount of polyester fiber.When the polyester fiber content is 1.5wt%,the single adsorption rate is up to 12 times,and the number of repeated adsorption times Up to 38 times;follow-up through a variety of flame retardants?aluminum hydroxide,melamine,pentaerythritol,ammonium polyphosphate?to add modified gel for flame retardant test,we learned that ammonium polyphosphate has the best flame retardant effect,of which ammonium polyphosphate When the content is10wt%,the flame retardant effect is the best:the LOI is as high as 28%,and the UL-94 test reaches the V-0 level;the total heat release?THR?is 30.0k W/m²,and the decrease rate is69.8%;PHRR)67.8 MJ/m²,a decrease of 29.9%;the peak smoke generation rate PSPR?m²/s?is 0.15m²/s,a decrease of 53%;the total smoke production?TSP?is 12.6m²/s,a decrease of 82%;FGR value 1.94k W/m²·s decreased by 80%,compared with pure toughened gel CC data are significantly reduced,that is,after the introduction of fiber and flame retardant,aerogel Department achieve good toughness and flame-retardant effect.