Design And Synthesis Of Hydrophobic Flame Retardants And Their Finishing Of Cotton Fabric

Cotton fabric is widely used in production and life.However,cotton fabric is flammable and has potential fire risk,so the flame retardant finishing of cotton fabric is of great significance to the safety of production and life.At present,tetramethylol phosphine chloride and N-hydroxymethyl-3-?dimethoxyphosphonyl?propionamide flame retardants commonly used in Proban finishing and Pyrovatex CP finishing can give cotton fabric good flame retardancy and washing resistance,but these two kinds of flame retardants will release formaldehyde which is harmful to human body during the usage.In recent years,some new flame retardants and finishing methods have emerged,such as ultraviolet initiated polymerization?UV-curable?based on olefin-containing flame retardants,sol-gel finishing based on silane groups?sol-gel?and layer-by-layer based on positive and negative nanoparticles,etc.,which have defects in flame retardancy and washing resistance.Based on this,a flame retardant with high flame retardant efficiency,washability and no formaldehyde release was designed and synthesized in this paper,and it was finished on cotton fabric to give cotton fabric excellent flame retardancy.Additionally,in some application fields,cotton fabric is required to have both flame retardancy and hydrophobicity,this kind of cotton fabric is non-flammable and self-cleaning,and is not easy to breed bacteria,such as curtains,sand release,car cushions and so on.However,there are few reports on the finishing methods which are both hydrophobic and flame retardant.Fluorine-containing compounds are used as finishing agents in traditional hydrophobic finishing,and fluorine is harmful to the environment and human body.In this paper,a fluorine-free hydrophobic flame retardant finishing agent was designed and synthesized,and the hydrophobic and flame retardant cotton fabric was prepared.The main work of this paper is as follows:?1?Synthesis of N-ethanolyl-N-methylenephosphonic acid ammonium-N-ethylammonium phosphate?ACMPEP?flame retardant and its application in cotton fabric.A new flame retardant containing-OH group and reactive-P=O?ONH₄?₂ groups was synthesized from diethanolamine,formaldehyde,phosphoric acid,phosphorous acid and urea.The structure of ACMPEP was verified by Nuclear magnetic resonance spectroscopy?NMR?and the successful grafting onto cotton fabric was confirmed by Fourier Infrared Spectroscopy?FTIR?analysis.In the process of high temperature finishing,flame retardants not only react with cellulose to form P-O-C covalent bond,but also polymerize to a certain extent.The results showed that the cotton fabric treated with the flame retardant has high flame retardancy and excellent washing resistance.The limiting oxygen index?LOI?of cotton fabric treated with 30%ACMPEP was increased to 42.0%.The flame retardant property of cotton fabric after 50 laundering cycles was good.The thermogravimetric?TG?test showed that the thermal degradation route of the finished cotton fabric changed.The results of thermogravimetric-infrared spectroscopy?TG-FTIR?showed that the amount of flammable gas released from flame retardant cotton fabric decreased obviously.The results of cone calorimetry showed that the heat release rate?HRR?and total heat release?THR?of cotton fabric decreased significantly after treatment.The structure and surface morphology of cotton fiber changed little after treatment.After finishing,the strength of cotton fabric decreased and the stiffness increased.To sum up,ACMPEP can be used as an efficient and durable flame retardant for cotton fabric.?2?Synthesis of N-dimethyl octadecyl phosphate acrylamide?NDOPA?hydrophobic flame retardant and its application in cotton fabric.A new fluorine-free hydrophobic flame retardant finishing agent containing olefin group was designed and synthesized using acrylamide,formaldehyde,octadecyl alcohol and phosphorous acid as raw materials,and the structure of NDOPA was verified by NMR.The finished cotton fabric has hydrophobic and flame retardant properties.FTIR showed that NDOPA reacted with cotton fiber to form C-O-C covalent bond.The water contact angle?WCA?of cotton fabric treated with 10%NDOPA solution reached 157.5°,which reached the standard of superhydrophobicity.At the same time,the finished cotton fabric preserved the complete carbon frame in the vertical combustion test.After 30 laundering cycles,the water contact angle of cotton fabric is maintained at 149.5°.The vertical combustion test showed that the treated cotton fabric could still maintain a basically intact carbon frame after 30 laundering cycles.The TG test results showed that the thermal degradation route of the finished cotton fabric had changed.FTIR and EDX analysis showed that the finishing agent formed a covalent bond with cotton fiber.Therefore,cotton fabric has long-lasting hydrophobicity and flame retardancy.XRD and SEM analysis showed that the structure and surface morphology of cotton fabric changed little.NDOPA finishing agent can be used as a durable and environmentally friendly flame retardant for hydrophobic cotton.?3?Synthesis of ammonium octadecyl phosphate hydrophobic flame retardant?AMOP?and its application in cotton fabric.An environmentally friendly hydrophobic flame retardant octadecyl ammonium phosphate?AMOP?,was synthesized from octadecyl alcohol,phosphoric acid and urea.Its structure was verified by ¹HNMR,¹³CNMR and ³¹PNMR.AMOP can endow cotton fabric with flame retardancy and superhydrophobicity at the same time.The WCA and LOI of the treated cotton fabric can reach 161.8°and 27%.After 30 washing cycles,the hydrophobicity of cotton fabric is good.TG and TG-FTIR analysis showed that AMOP changed the thermal decomposition path of cotton fiber,and the treated samples released less combustible gas during thermal decomposition.The results of cone calorimetric test showed that the values of THR and HRR of treated cotton were significantly lower than those of control cotton.FTIR and EDX analysis showed that AMOP was successfully grafted onto cotton fabric by P-O-C group.The results of SEM show that AMOP could cause surface roughness.The fracture strength of treated cotton fabric decreased slightly,but it could meet the strength requirements of most application fields.The cotton fabric finished by AMOP has better hydrophobicity and flame retardancy.