Fabrication,propertv And Application Of Flame Retardant Shape Memory Epoxy Composotes

Shape memory epoxy(SMEP)is a chemically crosslinked shape memory polymer with good thermomechanical properties,chemical resistance and excellent dimensional stability.In recent years,SMEP has been favored by domestic and foreign researchers;however,most of epoxy resins have high-viscosity properties and require further solvent treatment to reduce their viscosity,resulting in waste of resources and air pollution.With the improvement of human environmental protection awareness,waterborne epoxy(WEP)using water as a solvent dispersion medium has received widespread attention,and it is one of the important branches of epoxy resin.Previous research by our team found that cured WEP has excellent shape memory performance,but WEP after curing is extremely easy to burn,and its Limited Oxygen Index(LOI)is less than 20%,which restrict its widespread applications.For this purpose,this work aims to study a multi-functional shape memory composite material with both shape memory property and good flame retardant property,a compound flame retardant was developed,and to study the effects of flame retardants on the mechanical property,shape memory property,and flame retardancy of WEP.And the composite material is applied to a polyester fabric,and it is desired to obtain a multifunctional fabric having excellent mechanical properties and flame retardancy and having infrared light irradiation and wrinkle removing function.The paper mainly includes the following three parts:Firstly,Ammonium polyphosphate(APP),which has excellent smoke suppression,non-toxicity and flame retardant effect,was used as a flame retardant,and prepared by emulsion blending,freeze drying and hot press forming processes.The APP/WEP composites were studied and the effects of APP on the mechanical property,thermal degradation property,shape memory property,and flame retardancy of the composites were investigated.The results showed that the flame retardancy of the composites was significantly improved with the increase of APP.When the APP mass fraction was 20%,the LOI value of the APP/WEP composites was 32.6%.Moreover,the APP/WEP composites still maintained good shape memory performance,and its shape memory recovery ratio and shape memory fixing ratio were both higher than 95%.However,APP had a large difference in polarity between the inorganic flame retardant and WEP matrix.With the increase of APP content,the mechanical strength of the APP/WEP composites decreased,and the flame retardant performance of WEP was limited.Secondly,in order to further improve the flame retardant property of the composites and inhibit the mechanical damage of APP to WEP,polydopamine(PDA)was compounded onto the APP surface by in-situ polymerization to obtain a composite flame retardant PDA@APP.The PDA@APP/WEP the composite were prepared by emulsion blending,freeze drying and hot press forming processes.The effects of PDA@APP on the morphology,mechanical property,thermomechanical property,thermal degradation property,and shape memory property and flame retardancy of composites were investigated.The results showed that PDA can effectively inhibit the damage of APP to the mechanical property of WEP.Under the same filler content,the breaking strength of the PDA@APP/WEP composites was higher than that of the APP/WEP composites.Furthermore,the flame retardant synergy between PDA and APP existed.The effect further improved the flame retardant property of the composite.For example,the peak heat release rate and the total smoke yield of the 15wt%PDA@APP/WEP composites were reduced by 58.4%and 64.5%,respectively.In addition,the PDA@APP composites had excellent shape memory performance and their shape recovery ratio and shape fixing ratio were both higher than 98%.Int addition,due to the excellent photothermal conversion performance of PDA,the PDA@APP imparted a shape memory effect to the WEP light drive during near-infrared irradiation.Finally,the PDA@APP/WEP emulsion(uncured state of the composite)was compounded to the polyester fabric by post-finishing.The results showed that the mechanical property of the polyester fabrics finished by PDA@APP/WEP emulsion has been significantly improved.When the post-finishing time was up to 3,the tensile strength of the polyester fabrics reached 97.87 MPa,which increased by 30.4%compared with the pure polyester fabric.After finishing,the shape memory performance of the polyester fabric was imparted,and the shape memory fixing ratio and the shape memory recovery ratio of the fabric showed an increasing trend with the increase of the finishing times.Compared with the finishing times,the shape memory fixing ratio and shape memory recovery ratio of the fabric were improved by 22.3%and 33.1%,respectively.After finishing,the flame-retardant performance of the fabric was effectively improved,compared with the pure polyester fabric,PHRR decreased by 93.49%for the sample finishing for 4 times.In addition,the polyester fabric finished by the PDA@APP/WEP emulsion had excellent light(near-infrared light)wrinkle-removing function.