Halogen-free Flame Retardant Modification Of Polyester Fabric

Polyester(PET)fabric is widely used in people's daily life with excellent performance,but it is flammable and may pose safety hazards.Therefore,it is necessary and valuable to carry out flame retardant research on PET fabric.In this paper,three bio-based halogen-free flame retardant systems were employed to modify PET fabric.While improving flame retardant ability,the smoke release during combustion and vulnerably contaminate performance of PET fabric were reduced.The mechanism of flame retardant PET fabric with different flame retardant systems was analyzed.The results of research mainly include three aspects:Firstly,ammonium phytate(APA)which was synthesized by phytic acid and urea was used as acid and gas source with cyclodextrin(CD)as carbon source to construct an intumescent flame retardant coating on PET fabric.The limiting oxygen index(LOI)of PET fabric after flame retardant finishing was increased from 19.0%to 29.5%.The vertical burning test showed that the damage length of modified PET fabric was reduced from 24.5 cm to 4.4 cm and no droplets generated during combustion,which meant carbon forming ability of fabric was significantly improved.In the cone calorimeter test(CCT),peak heat release rate(pHRR)of coated PET fabric was significantly decreased from 419.6 kW/m² to 158.3 kW/m².The mechanical properties of PET fabric were enhanced after flame retardant finishing,the radial breaking strength was increased from 465.1 N to 974.2 N.The skin irritation test results indicated that APA/CD modified PET fabric was non-irritating and had good biological safety.Secondly,waterborne aqueous polyurethane emulsion compounding of ferrocene-cyclodextrin inclusion compound(FC),CD,ammonium polyphosphate(APP)and melamine(MEL)was coated on PET fabric.Test results indicated the LOI of PET fabric reached 28.1%and the damage length reduced from 24.5 cm to 11.8 cm when the amount of FC was 4 phr.The Fe generated by FC during combustion process could serve as a nucleation center to accumulate soot around the core,accelerate soot oxidation,hence the smoke maximum density(SMD)of PET fabric after coating was decreased from 58.5%to 37.3%.Thermogravimetric analysis(TGA)data showed the residual carbon of PET fabric at 700? was increased from 12.4%to 24.0%.Meanwhile,the radial breaking strength of PET fabric was increased from 465.1 N to 1024.5 N after coating,which indicated the mechanical properties of PET fabric significantly increased.Finally,PET fabric was finished by flame retardant and super hydrophobic composite coatings.Intumescent flame retardant layer was forming with starch(ST),polyethyleneimine(PEI)and APP,and hydrophobic layer build by nano-SiO₂ and polydimethylsiloxane(PDMS).After coating,the LOI of PET fabric increased to 28.4%,and no droplets were generated during the combustion process.In CCT,the pHRR of coated PET fabric was reduced by 47.4%compared with pure PET fabric.Coated PET fabric reached super hydrophobic level with a water contact angle(WCA)of 150.8° and showed excellent anti-fouling ability.Hydrophobic and lipophilic groups as methyl and siloxane on the surface of modified PET fabric made it could be used for oil-water separation.The modification with flame retardant and super hydrophobic composite coating on PET fabric can broaden the field of application and improve safety in the use of PET fabric.