Preparation And Application Of Silicon-Containing And Phosphorus-Containing Flame Retardant Polyvinyl Acetate Emulsion

Polyvinyl acetate(PVAc)emulsion is one of the commonly used safe and environmentally-friendly adhesives.It has many excellent properties,but poor thermostability limits its application.Therefore,it is practical and practical to improve the heat resistance of the emulsion and impart flame retardancy to the emulsion.A variety of flame retardant PVAc emulsions were synthesized by pre-emulsified semi-continuous emulsion polymerization process and their applications were studied.The main research work and results are as follows:The surface of the attapulgite(ATP)was separately grafted by coupling reaction using Methyl vinyl dichlorosilane(MVDCS),dimethyl vinyl chlorosilane(CDMVS),γ-methacryloxypropyltrimethoxysilane(KH-570),vinyl tris(β-methoxy Ethyl ethoxy)silane(CG-172)to prepare an attapulgite-silicone monomer having silicon-rich element and double bond.The structure was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD)and scanning electron microscopy(SEM).The properties of the attapulgite-silicone monomer were examined by contact angle(CA)and thermogravimetry(TGA).The effects of the type and amount of silane coupling agent on the grafting effect were investigated.The results show that the modification effect is best when the mass ratio of MVDCS to attapulgite is 3:1,the inorganic-organic silicone flame retardant has good hydrophobicity and a reactive functional group.In order to further enhance the flame retardancy of the PVAc emulsion,a polymeric flame retardant monomer Trivinylsilyl oxyphosphine oxide(TVSOPO)was prepared by nucleophilic substitution reaction using trishydroxymethylphosphine oxide(THPO)and methylvinyldichlorosilane(MVDCS).The unique structure was characterized by FT-IR,XRD and SEM.In addition,the synthesis conditions of TVSOPO were investigated,and the effects of solvent type,dosage and reflux time on product yield were investigated.The results showed that when the ratio of THPO to MVDCS was 1:1.5,the amount of solvent N,N-dimethylformamide was 20 mL and the reflux reaction was carried out for 5 h,the yield was 68%.PVAc emulsion was synthesized by copolymerizing attapulgite-silicone monomer and silicon-phosphor monomer with vinyl acetate.The effects of the addition mode and amount of attapulgite-silicone monomer,the amount of protective colloid and the reaction temperature on the quality of the emulsion and the propertiesof the latex film were investigated,and attempts to apply a silicon-based flame retardant PVAc emulsion as a paper surface enhancer.The flame retardant properties of the emulsion on paper,wood,cloth and carpet were tested by the horizontal/vertical combustion method.The results show that the silicon-based emulsion prepared by MVDCS modified attapulgite and the silicon-phosphorus emulsion with 1.0% TVSOPO added have the best flame retardant effect.Therefore,the flame retardant emulsion can be applied to a paper surface enhancer or wood adhesive and a carpet backing adhesive having a flame retardant effect.