Design,Preparation And Properties Of Highly Durable Transparent Flame-Retarded Hydrogel Interlayer

Glass components are widely used in modern buildings,and their fire-resistance is gaining increasing interest.However,the domestic research in the field of fireproof glass started late.It is extremely urgent to break through the key technologies of composite fire-proof glass in terms of the fire resistance,light transmittance and anti-aging resistance.In this thesis,transparent flame-retarded hydrogel with excellent heat insulation performance were designed and prepared by molecular design,chemical modification and aqueous solution polymerization.The effects and laws of structural composition of transparent flame-retarded hydrogels on their light transmittance,pyrolysis characteristics,fire resistance,char formation properties and aging resistance were studied by combining materials science and fire science,and the mechanism of fire resistance and anti-aging resistance of transparent flame-retarded hydrogel in fireproof glass were explored.The main work and achievements of this thesis are as follows.(1)Poly(acrylamide-acrylic acid)(P(AM-co-AA))was synthesized by molecular design from acrylamide(AM)and acrylic acid(AA)respectively.Then,the compound flame retardants were introduced,and the cross-linking agent and initiator were added to design and prepare transparent flame-retarded hydrogel,which was applied to the fireproof glass.The structural characteristics and physical and chemical properties of transparent fire-retarded hydrogel were controlled by changing the mass ratio of the hydrogel.The results of optical transmittance analysis show that the light transmittance of transparent fire-retarded hydrogel was negatively correlated with the AA content in(P(AM-co-AA)).The results of heat insulation performance analysis show that the heat insulation performance of the composite fireproof glass decreases first and then increases with the increasing AA content in P(AM-co-AA).When the mass ratio of AA to AM in P(AM-co-AA)is 4:1,the obtained transparent flame-retarded hydrogel interlayer exhibits the best thermal insulation,light transmittance and aging resistance.The expansion height of the char layer reach 5.2 cm and the light transmittance is85.4 %.(2)Acrylamide(AM)-methacrylic acid(MAA)copolymer(P(AM-co-MAA))was synthesized by aqueous solution polymerization and compounded with intumescent flame retardants and curing agent to prepare transparent flame-retarded hydrogel for application in fireproof glass.The results show that when the mass ratio of AM and MAA is 4:1,the obtained composite fireproof glass exhibits the best light transmittance and fire resistance,where the light transmittance is as high as 86.1%.The high light transmittance of P(AM-co-MAA)hydrogel is mainly attributed to the complexation of acrylamide(AM)and methacrylic acid(MAA)units in the polymer network and the intramolecular hydrogen bonds are easier to form and more stable due to the hydrophobic interaction of methyl groups in the polymer chain.Char layer analysis shows that ammonium polyphosphate(APP)and ammonium dihydrogen phosphate(ADP)formed cross-linked and aromatic structures with high stability during the combustion process,which significantly enhance the heat insulation performance and char formation ability of the hydrogels and effectively prevent the heat transfer,thus showing the best fire resistance and aging resistance.(3)Polyethylene glycol 1000(PEG 1000)was blended with PAM,P(AM-co-AA),P(AM-co-MAA)and other polymers to form an interpenetrating network,after which transparent flame-retarded hydrogel was prepared by adding silicon phosphate,alum and other flame retardant liquids for application in fireproof glass.The results show that the formation of metal coordination bonds between high-valent metal salts and polymer interpenetrating networks can effectively enhance the thermal stability of transparent flame-retarded hydrogel and maintain high light transmittance of fireproof glass.The presence of polyethylene glycol molecular chains also promotes the formation of more P-O-C structures to enhance the denseness and expansion of the char layer,which in turn effectively inhibits the volatilization of combustible gases and heat transfer,thus imparting the transparent flame-retarded hydrogel with better heat insulation properties.In addition,the P(AM-co-MAA)/PEG interpenetrating network structure can effectively enhance the aging resistance of transparent flame-retarded hydrogels.By combining the theories and methods of fire science and materials science,this thesis designs and prepares transparent flame-retarded hydrogel interlayer with excellent comprehensive performance,which provides important theoretical support to solve the key problems of composite fireproof glass in terms of light transmittance,fire resistance and aging resistance enhancement,and also provides technical support to carry out related research work.40 figures,15 tables and 76 references are presented in this thesis.