| Cotton textiles have many advantages,such as good moisture absorption and heat preservation ability,skin-friendly,low price and so on.However,they are easy to burn in the air,which pose a great threat to people’s life and property safety,and limit the expansion of cotton fabric in other fields.Therefore,it is very important to develop flame-retardant cotton fabrics to improve its safety and expand its application fields.Traditional flame retardants used in cotton,such as halogen,phosphorus and nitrogen flame retardants,are generally harmful to human health and have low flame-retardant efficiency.Moreover,they all come from non-renewable resources such as petrochemical and coal,which are not in accord with the contemporary social concept of sustainable development.Therefore,the green and non-toxic bio-based flame retardants from a wide range of sources are considered to be a strong substitute for traditional flame retardants.However,the existing processes of producing flame-retardant cotton fabric with bio-based flame retardants often make the cotton fabric have poor hand-feeling,and even affect its normal use.In addition,the single flame-retardant function can no longer meet people’s demand for textiles.Flame-retardant and hydrophobic cotton fabric not only has the ability of water and stain resistance,but also prolongs the service life of flame-retardant fabric,which is helpful to expand its application in the field of clothing,home decoration and so on.Aiming at the above problems,this paper proposed a new method to prepare flame-retardant cotton fabric with the flame-retardant system of bio-based CS / PA.The deposition position of flame-retardant complex in cotton fabric was adjusted by electrospinng so as to avoid clogging the pores of cotton fabric.By constructing a hydrophobic layer on its surface,the multifunctional cotton fabric with good hand-feeling,flame-retardant,hydrophobic and washable properties was prepared.The specific research contents and achievements are as follows:(1)Preparation of CS/PEO/PA flame-retardant membrane: The spinning solution parameters of CS/PEO nanofibers with good morphology and the PA adsorption capacity of CS/PEO electrospun membrane with different thicknesses were investigated.The results showed that when CS: PEO=90: 10 and the total concentration was 3.5%,the fineness of electrospun fibers was uniform,and the diameter was between 110 nm and 160 nm.The sprayed PA formed an obvious coating layer on the surface of the fibers,and formed a bonding point at the joint of the fibers.The phosphorus content on the fiber membranes of different thicknesses had saturation values.(2)Preparation of flame-retardant cotton fabric by bio-based CS/PEO/PA electrospun coating: thin,medium and thick cotton fabrics were loaded with different thickness of CS/PEO/PA electrospun coating.Through a series of tests,the flame-retardant properties,thermal stability and combustion behavior of the prepared samples were characterized and analyzed.The results showed that the matching between the weight of cotton fabric and the thickness of electrospun coating directly affected the flame-retardant effect.The THR and HRR of the cotton fabric treated with flame-retardant treatment decreased to varying degrees,and the THR decreased by about 68% at most compared with the untreated cotton fabric.The flame-retardant mechanism of CS/PEO/PA electrospun flame-retardant layer was embodied in two aspects.In the process of thermal degradation,PA produced phosphoric acid,which catalyzed CS to form carbon,and the produced phosphorous free radicals could eliminate the free radicals in the flame zone,thus interrupting the combustion reaction.CS released non-flammable gases such as ammonia and nitrogen at high temperature,which thickened the carbon layer and also could dilute the concentration of flammable gases.(3)Preparation and properties of flame-retardant and hydrophobic cotton fabric: flameretardant and hydrophobic cotton fabric was prepared by spraying cationic polyurethane hydrophobic agent on the surface of flame-retardant cotton fabric coated by electrospinning.The influence of the concentration of hydrophobic agent on the hydrophobic properties of the fabric was studied.The effects of preparation method and thicknesses of flame-retardant electrospun membranes on mechanical properties of flame-retardant and hydrophobic cotton fabric were investigated,and this paper also compared the washing durability of the flame-retardant cotton fabric before and after hydrophobic finishing.The test results showed that,when the concentration was 5%,the hydrophobic agent could form a complete and continuous hydrophobic film on the surface of the flame-retardant cotton fabric coated by electrospinning,the static contact angle could reach 150.7°.The results showed that the electrospun coating method could reduce the influence on the mechanical properties of cotton fabric more than the self-assembly method of impregnation.Flame-retardant and hydrophobic cotton fabric had better flame-retardant washing durability,LOI could still reach 25.2% after 8 times of washing,and had self-extinguishing effect,the static contact angle could reach 101.3°.In conclusion,an innovative method of preparing flame-retardant cotton fabric by bio-based CS/PA flame-retardant system was proposed in this paper.Cotton fabric was used as the receiving substrate to prepare CS/PEO electrospun membrane by electrospinning.CS/PEO electrospun membrane was used as the adsorption template for depositing PA on the surface of the fibers,the flame-retardant cotton fabric was then prepared.This method minimized the effect of the flameretardant treatment on the mechanical properties of cotton fabrics.By building a hydrophobic layer on the fabric surface,the flame-retardant,hydrophobic and washable multifunctional cotton fabric was prepared,which provided a new solution for the fabrication of bio-based flameretardant cotton fabric. |
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