Flame Retardant Finishing Of Polyester/Cotton Fabric And Its Performances

Polyester/cotton fabric（PC）combines the comfort and breathability of cotton and the mechanical properties and chemical stability of polyester,which is widely used in home decoration,medical apparel,and aerospace fields.However,PC is extremely easy to burn,as a result of its special"wick effect",the combustion process is more intense,posing a greater fire hazard that might put lives and property in peril.Therefore,it is particularly important to carry out flame retardant finishing of PC.The existing halogen and phosphorus flame retardants such as Pyrovatex CP have excellent flame retardant effects,but there is the release of toxic and harmful substances like dioxins and formaldehyde during use,which endangers the environment and human health.As a result,they have been gradually banned.Seeking green and environmentally friendly ecological flame retardants to achieve flame retardant finishing of PC has become an effective way to solve the above problems.In this paper,biomass phytic acid（PA）and chitosan（CS）were used as flame retardants to construct intumescent flame retardant coating on the surface of PC by impregnation baking to prepare flame retardant fabric（PC-PA/CS）.On this basis,in order to improve the durability of PC-PA/CS,methyltriethoxysilane（MTES）and dihydroxy-terminated polydimethyl siloxane（PDMS-OH）were used to silane modify PC-PA/CS to prepare durable flame retardant PC（PC-PA/CS/AP）.In order to further realize the active defense function of PC when threatened by fire,carbon nanotubes（CNT）were introduced into the flame retardant finishing solution to prepare PC with fire warning,and flame retardant function（PC-PA/CS/AP₆/CNT）.The research content and results of the paper are as follows:（1）Flame retardant finishing and performances of polyester/cotton fabric:Using PA and CS as flame retardants,the intumescent flame retardant coating was constructed on the surface of PC by impregnation baking method to prepare PC-PA/CS.The influence of the preparation process on the flame retardant performance was studied,and the optimal preparation process was obtained through process control:reaction temperature was 160℃,reaction time was 120 s,CS concentration was 30 g/L,and PA concentration was 400g/L.Through the limiting oxygen index test（LOI）,the LOI value of PC-PA/CS was significantly increased from 17.8%to 28.7%of PC,and by ignition in the air,the droplet phenomenon of the fabric disappeared,which showed good flame retardant performance.The peak heat release rate（PHRR）and total heat release（THR）of PC-PA/CS were significantly lower than those of PC by 33.53%and 25.18%,respectively,effectively reducing heat release.By the microscopic morphology and Raman spectroscopy of char residue,the construction of expanded flame retardant coating promoted the dehydration and carbonization of the fabric,and the stable char layer structure hindered the further combustion of the fabric,which had the condensed phase flame retardant mechanism.（2）Durable flame retardant finishing and performances of polyester/cotton fabric:The polysiloxane solution（AP）containing hydroxyl groups was prepared by MTES and PDMS-OH,and alternately impregnated with flame retardant finishing solution on the surface of the fabric to form a durable flame retardant coating,and durable flame retardant PC（PC-PA/CS/AP）were successfully prepared.Through process adjustment,PC-PA/CS/AP₆ worked best when the AP concentration was 6%.The LOI value of PC-PA/CS/AP₆ reached 30.1%,and the LOI value can still reach26.9%after 20 washes,which had good durability.In the combustion test,compared with PC,PHRR,THR and combustion growth rate（FGR）of PC-PA/CS/AP₆ were reduced by 56.99,33.21 and 61.99%,respectively,and the safety performance was significantly improved.Through the thermogravimetric test（TG）,the degradation rate of PC decreased,the thermal stability was significantly improved,and the amount of residual char increased.By the micromorphology and raman spectroscopy of char residue,the addition of polysiloxane formed the synergistic flame retardant effect of phosphorus and nitrogen silicon,which further promoted the dehydration of the fabric into char,increased the degree of graphitization of the char layer,and played the condensed phase flame retardant effect.（3）Preparation and performances of flame retardant polyester/cotton fabric with fire warning function:CNT was introduced into the flame retardant finishing liquid,and flame retardant PC with early warning function（PC-PA/CS/AP₆/CNT）was successfully prepared.When the amount of CNT was 2 wt%,PC-PA/CS/AP₆/CNT₂ was burned only 2 s to issue an early warning signal,and it can continue to warn within a test time of 120 s,with excellent sensitivity and stability.The LOI value test showed that the LOI value of the fabric was as high as 32.3%,which had excellent flame retardant performance.According to TG,the pyrolysis rate of the modified fabric decreased and the thermal stability was significantly improved.Compared with PC,the total amount of PHRR,THR and smoke release（SPR）with PC-PA/CS/AP₆/CNT₂ combustion decreased by 88.01,34.18 and 11.56%,respectively,reducing the release of heat and smoke.During the combustion process,the flame retardant coating promoted the dehydration of the fabric into charcoal and improved the degree of graphitization of the char residue.CNT increased the compactness and graphitization degree of the char layer,which improved the flame retardant performance of the fabric and the conductivity of the char layer.