Study On Flame Retardancy Of Natural Cellulose Paper/Clay Through Layer By Layer Self-assembly

With the extensive application of paper materials and the increasingly severe fire control,paper materials in flame retarding properties have high request.In order to reduce the impact on human health and the ecological environment,the use of efficient,environmentally friendly flame retardants in paper materials for the flame retardant treatment is becoming a global hot spot.In this work,flame retardant treatment on cellulose paper was by the layer by layer self-assembly technology and coating technology.The influence of the counter metal ions on the structure and thermal property of anionically modified montmorillonite（MMT）was studied.Meanwhile the flame retardantcy of anionic modified montmorillonite on the surface of cellulose paper was studied.The anionically modified montmorillonite and flame retarded paper were characterized by X-ray diffraction（XRD）,thermogravimetric analyzer（TG）,scanning electron microscopy（SEM）,air permeability tester and horizontal burning test.（1）Both of the counter metal ion modified montmorillonite（MMT）and anionically modified montmorillonite（MMT）were studied.It showed that metal ion was intercalated into the layers of montmorillonite（MMT）,and could help stearic acid anion enter the layer.The interlayer spacing of anionically modified montmorillonite（MMT）increases from0.98nm to values between 1.56 and 1.58nm,and the content of the organic compound are increased.（2）According to the flame retardancy of surface modified paper using layer by layer self-assembly method,it was found that the treatment method of montmorillonite-cetyltrimethylammonium chloride（MMT-CTAC）and montmorillonite-polyethylenimine（MMT-PEI）was better than CTAC-MMT and PEI-MMT.（3）When the layer by layer self-assembly method was adopted in this work,the effect of the four solution system on the flame retardantcy of paper was as follows:montmorillonite-zinc chloride-sodium carboxymethylcellulose（MMT-ZnCl₂-CMC）>MMT-CaCl₂-CMC>MMT-FeCl₃-CMC>MMT-MgCl₂-CMC.The paper treated by MMT-ZnCl₂-CMC-10 can extinguish,while the paper treated by MMT-ZnCl₂-CMC-15 was difficult to ignite and had good flame retardantcy in the horizontal burning test.In addition,the permeability results show that using sodium montmorillonite（Na-MMT）suspensions modified cellulose paper by layer by layer self-assembly technique of can significantly reduce the permeability of the paper.Especially the paper treated by MMT-ZnCl₂-CMC,permeability decreased with the increasing in the number of self-assembled layer significantly.The permeability of the paper treated by MMT-ZnCl₂-CMC-15 has been decreased by 94%.And with the reduction of the permeability of the paper,the char formation was increased and the flame retardant property was improved.（4）The layered structure of the composite film material was prepared by using the counter metal ion montmorillonite and carboxymethyl cellulose sodium salt（CMC）.The results of XRD and SEM show that the carboxymethyl cellulose sodium salt（CMC）was intercalated into the interlayer of montmorillonite,and the distance between the layers was increased from 0.98nm to 1.79².46nm.Compared with the pure CMC film,the high temperature thermal stability and residual carbon content of the composite films formed by adding montmorillonite were obviously improved.In particular,the optical transmittance of CMC-Fe-MMT composite films decreased by 93.3%⁹3.8%,which shown that the Fe-MMT had excellent UV absorption properties.（5）Coated paper was prepared by coating technology using carboxymethyl cellulose sodium salt（CMC）solution and carboxymethyl cellulose sodium salt（CMC）/montmorillonite（MMT）composite.It was found that the gap between paper fibers was filled up,and shows smooth surface,which improve the high temperature thermal stability and permeability of paper.The high temperature thermal stability of paper coated by carboxymethyl cellulose sodium salt（CMC）/montmorillonite（MMT）composite is better than that of paper coated by carboxymethyl cellulose sodium salt（CMC）.In addition,paper coated by carboxymethyl cellulose sodium salt（CMC）burnt completely,while paper coated by carboxymethyl cellulose sodium salt（CMC）/montmorillonite（MMT）composite generated a layer of dense protective film on the surface in the combustion,which prevented the spread of the combustible gas and the heat,protected the base material,and even made the paper extinguish.