Study On Fire Safety And Anti-Aging Properties Of Silicone Acrylic Emulsion-Based Composite Coatings

The most effective way to reduce fires is to solve the flammability problem at the root of the material.Organic flame retardant coatings can reduce the flammability of the material surface,but they have the disadvantages of poor compatibility with the base material,durability,and weather resistance,and are prone to aging and cracking under the influence of natural factors,resulting in a decrease in flame retardant performance.Therefore,it is necessary to improve the flame retardancy and aging resistance of organic flame retardant coatings.In this paper,water-based silicone acrylic emulsion is used as film-forming material,wood is used as substrate,and carbodiimide-uretonimine is used to modify 4,4’-diphenylmethane diisocyanate(MDI-100L),aluminum diethylphosphinate(ADP)is used as a variable to prepare organic composite flame retardant coatings to obtain the formula with the best flame retardancy.The main results of the paper are as follows:Add MDI-100L to the silicone medium to synthesize MDI-100L/silicon acrylic emulsion-based composite coating,generate polyurea molecules to block heat transfer,and enhance the fire safety performance of the coating.When the content of MDI-100L is 1 wt%,the flame retardancy of MDI-100L/silicon acrylic emulsion-based composite coating is the best,and the p-HRR value decreases by 36.05%.In the pyrolysis kinetics,the Z.-L.-T.three-dimensional diffusion-3D model is calculated and determined by the improved Coats-Redfern integral method,and the pyrolysis process is fitted.The results show that the pyrolysis activation energy(E_α)increases by 136.96%in the temperature range of 135-210℃,and increases by 6.63%in the temperature range of 370-455℃.Using ADP as a synergist to add to MDI-100L/silicon acrylic emulsion-based composite coating to synthesize ADP/MDI-100L silicon acrylic emulsion-based composite coating,generate aluminum phosphate solid phase residues to form a stable carbonization layer to inhibit coating combustion,and is based on MDI-100L/silicon acrylic emulsion-based composite coating,the fire safety of the composite coating enhances again.When the content of ADP is 1 wt%,the flame retardancy of ADP/MDI-100L/silicon acrylic emulsion-based composite coating is the best,and the p-HRR decreases by 37.61%.In the pyrolysis kinetics,the Z.-L.-T.three-dimensional diffusion-3D model is calculated and determined by the improved Coats-Redfern integral method,and the pyrolysis process is fitted.The results show that E_αincreases by 23.4%in the temperature range of 300-380℃,and increases by 21.5%in the temperature range of 380-430℃.The aging resistance of coatings is investigated using an ultraviolet artificial weathering tester.The experimental results show that the flame retardancy of the coating after the aging test is reduced,but the water resistance is enhanced.Under the same aging conditions,ADP/MDI-100L/silicon acrylic emulsion-based composite coatings have better flame retardancy than MDI-100L/silicon acrylic emulsion-based composite coatings,indicating that ADP has the effect of delaying anti-ultraviolet aging and delaying the reduction of flame retardancy of coatings speed.They determined the colorimeter that as the anti-ultraviolet aging time increases,the color of the coating gradually becomes darker and yellower,indicating that the law of aging affects the effect of the coating display from the color difference of the coating.In summary,this paper successfully prepared ADP/MDI-100L/silicon acrylic emulsion-based composite coatings with anti-ultraviolet aging properties,which improve fire safety.Coatings provide a certain reference for further improving the comprehensive performance of coatings in the future.