Design And Performances Of Multifunctional Flame-retardant Cotton Fabric Coatings Based On Biomass Materials And Two-dimensional Materials

As a natural fiber fabric,cotton has a wide range of applications in clothing,interiors and packaging due to its softness,breathability and biodegradability.However,cotton fabrics are extremely flammable,especially when used as indoor home or decoration,and can easily lead to serious fire accidents caused by the burning of other materials,so flame retardant treatments for cotton fabrics are essential.With the the requirements of sustainable development,most halogen-containing flame retardants and traditional phosphorus-nitrogen flame retardants are gradually banned or restricted because of the environmental,health and smoke hazards.Thus,the development of environmentally friendly flame retardants is imperative.In addition,with the development of science and technology,single-function textiles can no longer meet needs,and functional cotton fabrics can better meet the pursuit of people.Many biomass materials can replace petroleum-based flame retardants because they have a high char-forming ability or contain flame retardant elements such as phosphorus and nitrogen.Among the organic nanomaterials,the two-dimensional laminate materials have excellent physical barrier properties and can effectively isolate the diffusion of thermal mass in combustion,and can promote the formation of a dense and stable char layer,which is a good flame-retardant or smoke suppressant.At the same time,two-dimensional materials have other special properties such as light,heat and electricity,which when used as coatings make the performance of the material no longer limited to a single,can achieve the diversification of materials,functional development,to meet the diverse needs of people.Therefore,this work aims at the design and development of environmentally friendly multifunctional cotton fabric,design or prepare bio-based intumescent flame-retardant coating and then combine it with different two-dimensional layered materials,to construct green composite coating with multiple functions.Thermal stability and combustion of the coated cotton fabric were investigated in-depth and the flame-retardant mechanism was systematically analyzed,and the synergistic flame-retardant effect between the bio-based intumescent flame retardant and the two-dimensional layered material was investigated.Finally,other properties such as self-cleaning,conductivity and UV resistance of cotton fabric of the cotton fabric were explored.The specific findings of the study are as follows as follows:1.polyethyleneimine/g-C₃N₄（P/G）and polyethyleneimine/phytate（P/PA）were deposited on the surface of cotton fabrics as flame retardant coatings using layer-by-layer self-assembly techniques.During combustion,the P/PA coating can be decomposed to form an excellent intumescent char layer,while the underlying insulating coating P/G not only enhances the thickness and strength of the charcoal layer,but also acts as a physical barrier,and the two act synergistically to effectively isolate heat and oxygen during combustion,resulting in a significant improvement in the thermal stability of the cotton fabric,and achieved self-extinguishing in the vertical combustion test.The limited oxygen index value was increased to 30.5%and the peak heat release rate and total heat release rate decreased by 76.9%and 77.1%,respectively,and the good flame retardant properties were maintained after several washes.This simple,green approach offers new perspectives for the development of multilayered flame-retardant coatings containing of bio-based and two-dimensional materials on cotton fabrics or other substrates.2.A composite coating with flame-retardant and durable self-cleaning abilities was designed and constructed on the surface of the cotton fabric based on synthetic g-C₃N₄（GCN）and phosphorylated chitosan（PCS）.Compared to uncoated cotton fabric,the heat release rate of the coated cotton fabric was reduced by 55.8%,the limiting oxygen index was 30.1%and the desired self-extinguishing effect was achieved in vertical combustion tests.In addition,based on the outstanding photocatalytic performance of GCN,which is enhanced by the strong adsorption capacity of PCS,the coated cotton fabric showed excellent and long-lasting photodegradation of a variety of organic dyes and can be used for self-cleaning of contaminants on the surface of cotton fabrics.This work offers a new approach to the realization of multifunctional textiles and the expansion of their applications.3.The bio-based swelling flame retardant PACDU was prepared using phytic acid,cyclodextrin and urea as reactants.A new strategy for the fabrication of multifunctional cotton fabrics was introduced,involving with the sequent coating of PACDU,the two-dimensional material MXene and the hydrophobic long-chain alkyl silane OTMS were constructed on the surface of cotton fabric.The limited oxygen index of the cotton fabric was increased to 36.7%,the peak and total heat release rate were reduced by 74.4%and 62.4%and the cotton exhibit self-extinguishing during combustion.In addition,the constructed MXene conductive network greatly improved the electrical conductivity of the fabric and realized a fast-thermal-response at low voltages.The OTMS treatment resulted in a water contact angle of 141°on the surface of the coated cotton fabric,which showed good resistance to common dyes and contaminants,reducing the impact of frequent washing and pollution from outside on its normal function.This work has prepared a novel high-efficiency green bio-based flame retardant for flame retardant coating of cotton fabric,and the coated cotton fabric has excellent electrical conductivity,anti-fouling and flame retardant properties,which is expected to be applied in the field of wearable electronic devices.4.By impregnation and in-situ growth of PACDU and two-dimensional layered LDH on the surface of the cotton fabric,a composite coating with flame retardant,smoke inhibition and UV resistance was constructed.The in-situ growth of LDH was uniformly distributed on the surface of the cotton fabric,which not only further improved the flame retardant property of the PACDU treated cotton fabric,but also reduced the smoke emission caused by PACDU.Compared with the PACDU treated cotton fabric,the deposition of LDH reduced the peak heat emission rate and total heat emission of the cotton fabric by 16.7%and 7.5%,respectively.Moreover,the maximum smoke density decreased by 32.9%and the smoke density rating was reduced to 5.6,which can effectively avoid the disasters caused by heat and smoke in fires.In addition,the introduction of PACDU and LDH increased the absorption and blocking capacity of the cotton fabric to UV light,so that it obtained good UV shielding performance.The cotton fabric prepared in this work is flame retardant,smoke suppressant and UV resistant,and has potential applications in protective clothing and other applications.