Preparation And Flame Retardant Properties Of Seaweed Fiber-based Composite Paper

Traditional paper has become a hidden danger to people because of its flammability.The flame retardancy of paper is generally improved by adding flame retardants.The main adding methods are: in-pulp addition method,coating method,impregnation method,spray method,sizing method and so on.However,these methods have defects,either have an impact on the mechanical properties of the paper,or the improvement of the flame-retardant ability of the paper is limited,and the extensive use of flame retardants will also cause harm to the environment.Calcium alginate fiber(Ca-Alg)is a renewable fiber with intrinsic flame retardancy.Using it as a raw material for preparing flame retardant paper can effectively reduce the use of flame retardants.It is found that the smoldering phenomenon exists during the combustion of Ca-Alg,and the smoldering is more serious in the dense state.In order to solve the smoldering of Ca-Alg,Ca-Alg-based composite paper was prepared by blending CaAlg with other fibers.Furthermore,the flame retardancy,combustion behavior and thermal stability of the composite paper were studied.1.Alginate fiber-based composite paper was prepared by mixing flame retardant lyocell fiber(FRL)and calcium alginate fiber(Ca-Alg)according to different mass fraction.The vertical flammability results show that when the mass fraction of FRL in the composite paper is 20-70%,the composite paper can meet the vertical flammability standard of flame retardant paper,and the smoldering of Ca-Alg can be effectively suppressed by FRL.SEM and Raman analyses show that FRL forms a dense carbon layer on the surface of Ca-Alg during combustion,which limits the mass/heat transfer.The combustion behavior of the composite paper was analyzed by cone calorimetry(CONE).When the mass fraction of FRL in the composite paper was 30%,the fire risk of the composite paper was the lowest,even lower than that of Ca-Alg;and the introduction of FRL reduces the effective heat of combustion of composite paper.Thermogravimetric(TG)analysis shows that the temperature of the maximum mass loss rate of FRL and Ca-Alg is similar,so it is beneficial to exert their synergistic effect.Based on these,the synergistic flame retardant mechanism of FRL and CaAlg in composite paper was proposed.2.Polyester(PET)and polyamide(PA)were mixed with Ca-Alg according to different mass fractions to prepare alginate fiber-based composite paper.The vertical flammability results show that when the mass fraction of PET or PA in the composite paper is 20%,PET or PA has the best smoldering effect on Ca-Alg,and the smoldering inhibition effect of PA on Ca-Alg is better than that of PET.SEM and Raman analysis showed that PET and PA were covered by thermal melting on the surface of Ca-Alg fiber,which weakened the mass/heat transfer and inhibited the smoldering of Ca-Alg.Cone analysis shows that the fire risk of composite paper is less than that of wood pulp paper.In addition,TG analysis showed that the intermediate products of Ca-Alg thermal degradation affected the degradation process of PA,and the possible smoldering of PA degradation products further inhibited the smoldering of Ca-Alg.3.Flame-retardant polyester(FRPET)and flame-retardant polyamide(FRPA)were mixed with Ca-Alg to prepare alginate fiber-based composite paper.Compared with composite paper which containing PET or PA,composite paper containing FRPET and FRPA have more obvious inhibitory effect on Ca-Alg smoldering.Especially when the mass fraction of FRPA in the composite paper is 30%,the flame retardancy of the composite paper meets the standard of vertical flammability of flame-retardant paper.