Flame Retardant Modification Of Cotton Fabric Based On Biomass Flame Retardant And Its Mechanism

Textile materials are important basic materials related to national economic development and people's livelihood.In recent years,with the continuous deepening of the concept of green and low-carbon recycling,cotton textiles derived from natural cellulose fibers have been applied from daily clothing,home decoration and home textiles due to their unique advantages such as green environmental protection,biocompatibility and biodegradability.It has expanded to many high-end emerging industries such as military medical,rail transit,aerospace,and flexible wear.However,the high flammability of cotton fabrics(LOI=18.63%)poses a serious threat to people's life and property safety.Therefore,the development and application of flame-retardant cotton fabric has important scientific significance and application value for improving its safety in use and expanding its application range.However,the current flame-retardant finishing of cotton fabrics still faces serious limitations of environmental friendliness,durability and strong damage.On the one hand,the use of halogen or organophosphorus flame retardant finishing agents with high flame retardancy will bring about bioaccumulation and release harmful substances such as hydrogen halides or formaldehyde,which threaten human health.On the other hand,the flame-retardant properties of halogen-free and formaldehyde-free flame-retardant finished cotton fabrics are weak.As the washing process progresses,its flame retardancy will quickly lose and cannot meet commercial requirements.Therefore,how to achieve environmentally friendly,high-efficiency,durable and flame-retardant cotton fabrics is a key issue that needs to be resolved in the field of textile fire safety research.Aiming at the contradictions of ecological flame retardancy,high efficiency and durability,and strong damage in flame retardant cotton fabrics,this thesis uses biomass phytic acid(PA)as a flame retardant to prepare phytic acid modified flame retardant cotton fabrics by combining impregnation and heat curing methods.The influence of process parameter such as the ratio of raw materials and reaction time on the grafting rate and flame retardancy of cotton fabrics was investigated.On this basis,in order to improve the smoke suppression ability,flame retardant efficiency and mechanical properties of COTP,the phosphorus-nitrogen-silicon synergistic modified flame retardant cotton fabric was prepared by one-pot method using polyethylenimine(PEI)and 3-glycidoxypropyltrimethoxysilane(GPTMS)as synergistic flame retardant.The synergistic relationship between flame retardants was investigated,and the flame retardant and smoke suppression mechanism of COTP/N/Si was discussed.In order to realize the full bio-based synergistic flame retardancy of cotton fabrics and further expand its application potential in the field of safety protection,tannic acid(TA)and PA were used as flame retardants to prepare flame retardant,antibacterial and UV resistant multifunctional cotton fabrics.The main research results are as follows:(1)Study on the preparation and flame retardant properties of phytic acid modified flame retardant cotton fabrics:The fusion strategy of impregnation and thermal curing was adopted to successfully graft PA onto the surface of cotton fabric to prepare phytic acid modified flame retardant cotton fabric.The effects of the mass ratio of COT,PA and Urea and reaction time on the grafting rate and flame retardancy of cotton fabrics were investigated.The optimal preparation process was as follows:M_COT?M_PA?M_Urea=1?3?6,t=90 min,T=130?,and the sample prepared under this optimized process was named COTP3-90.COTP3-90 has excellent flame retardant properties,LOI value can reach 42.53%,after 50 LCs standard washing test,it can still maintain 28.32%,and also exhibit excellent durability.Combustion behavior studies have found that the introduction of PA promotes the dehydration and carbonization of cellulose,COTP3-90was self-extinguishing,and its peak heat release rate(PHRR)and total heat release rate(THR)were reduced by 65.51%and 71.43%,respectively.Smoke emission(TSP)was reduced by 12.50%.TG-IR analysis of the gas phase cracking products found that the emission of volatile combustible gas was significantly reduced,indicating that PA can inhibit the release of volatile combustible gas and toxic gas.(2)Study on the preparation of phytic acid-polyethyleneimine-silane synergistic modification of flame-retardant cotton fabric and its smoke suppression performance:In order to further improve the smoke suppression and mechanical properties of COTP,PEI and GPTMS were used as synergistic flame retardants to prepare phosphorus-nitrogen-silicon synergistically modified flame-retardant cotton fabrics by one-pot method.The optimal preparation process was as follows:M_COT?M_PA?M_Urea?M_PEI?M_GPTMS=1?1?2?0.15?0.15,t=90 min,T=130?,and the sample prepared under this optimized process was named COTP/N/Si-90.Compared with COTP,COTP/N/Si-90 achieved better flame retardant efficiency,carbon length was only 6.20 cm,and UL-94 reached V-0 grade.Meanwhile,the tensile strength of COTP/N/Si increased by 9.43%-19.42%.Combustion behavior study found that the PHRR and THR of COTP/N/Si-90 decreased by 85.89%and 52.72%,respectively,and the TSP decreased by 47.22%.COTP/N/Si-90 exhibit excellent smoke suppression and high safety protection performance benefit from the synergism of phosphorus,nitrogen and silicon flame retardants.(3)Study on the preparation and performance of flame-retardant,anti-bacterial and anti-ultraviolet cotton fabric modified by phytic acid and tannic acid:In order to realize the full bio-based synergistic flame retardancy of cotton fabrics and further expand its application potential in the field of safety protection,tannic acid(TA)was introduced to prepare phytic acid-tannic acid synergistically modified flame retardant,antibacterial and UV resistant multifunctional cotton fabric.The optimal preparation process was as follows:the addition amount of TA was 0.25%,M_COT?M_PA?M_Urea=1?3?6,t=30 min,T=130?,and the sample prepared under this optimized process was named COTP@0.25TA.The flame retardant properties of COTP@TA were significantly improved,indicating the synergistic flame retardant effect of TA and PA.The thermal stability of COTP@0.25TA was significantly enhanced,and the residual rate reached 37.59%at800?.The mechanical properties of COTP@TA were also improved compared to COTP.The tensile strength and elongation at break of COTP@0.25TA in the warp and weft directions were maintained at approximately 80%and 91%of the raw cotton fabric,respectively.TA promotes the formation of carbon layer,and the graphitization degree of COTP@0.25TA was high.The inhibitory rates of COTP@0.25TA against S.aureus and E.coli were 99.99%and 100.00%,respectively.At the same time,the transmittance of COTP@0.25TA was significantly reduced,the UPF value can reach 46.02,indicating that it has UV anti-aging performance.In this thesis,the flame retardant cotton fabric with"durability+smoke suppression+environmental protection"was successfully prepared,which solved the problems of traditional flame retardant cotton fabric such as complex process,poor durability and toxicity.The multifunctional cotton fabric with"flame retardant+antibacterial+UV resistance"was obtained by functional modification,which expanded the application potential of flame retardant cotton fabric in the field of safety protection,and provided a novel technology for the sustainable development of cotton fabric.