Development Of Sepiolite-based Synergistic Flame Retardants And Research On Flame And Smoke Suppression Performance Of Polymer Materials

With the continuous progress of science and technology,polymer materials have been widely used in electronics,construction,transportation and other fields,but in the process of practical application,the flammability of polymer materials and the large amount of smoke and toxic gases produced during combustion seriously limit the application of polymer materials,so the research on flame retardant and smoke suppression is urgent;the intumescent flame retardant system has the characteristics of high efficiency,safety and environmental protection,and is widely used.The intumescent flame retardant system is highly efficient,safe and environmental friendly,and widely used,but it needs to be used in combination with other materials because of its defects in gas-phase flame retardant.As a natural mineral,seafoam has a porous structure,high temperature non-combustibility,easy availability of materials,good acid and alkali resistance and durability,etc.,and shows unique advantages in flame retardant and smoke suppression.Therefore,the flame retardant system using seafoam in combination with intumescent system can effectively improve the safety and reliability of polymer materials,which is a research direction with great application prospects.Therefore,in this paper,we developed a new porous structure of seafoam-based synergistic flame retardant and smoke suppressant（SEP@M）and compounded it with phosphorus-nitrogen intumescent flame retardant system（AGT）in EPDM and ABS matrix,and studied the effect of the addition of the compounded system on the flame retardant and smoke suppressant performance of polymer materials by testing and characterizing the flame retardant and smoke suppressant performance of the prepared composites.The effect of the compounding system on the flame retardant and smoke suppression performance of polymeric materials was investigated,and the flame retardant and smoke suppression mechanism of seafoam co-effective flame retardant and intumescent flame retardant system in matrix materials was investigated.The main work of this thesis is as follows.Due to the rich silica hydroxyl group on the surface of natural sepiolite（SEP）,its dispersion in EPDM matrix is poor,which reduces its flame retardant and smoke suppression efficiency.In order to solve the dispersion problem of natural sepiolite（SEP）in EPDM matrix,In the first part,five kinds of modifier were used to modify natural sepiolite（SEP）to prepare sepiolite based synergic flame retardant and smoke suppressant（SEP@M）to solve the dispersion of sepiolite in the matrix material and share with AGT expansion flame retardant system.EPDM/AGT/SEP@M composite material was prepared by melting blending method.The flame retardancy and smoke suppression properties of composites were studied.The results showed that compared with pure EPDM,the oxygen index of EPDM/AGT/SEP₈@YS₁ increased to 34.5%and44.92%.And it reaches V-0 in the UL-94 test.Cone calorimetry test results showed that compared with pure EPDM,EPDM/AGT/SEP₈@YS₁ PHRR decreased to 176.87k W/m²,a decrease of 49.8%.Compared with EPDM/AGT/SEP,the PHRR of EPDM/AGT/SEP₈@YS₁ decreased by 4.80%;The PSPR and TSP of EPDM/AGT/SEP₈@YS₁ were 0.024 m²/s and 8.84 m²,respectively,which were decreased by 75.3%and 41.9%compared with pure EPDM and 22.58%and 12.91%compared with EPDM/AGT/SEP,respectively.ABS materials are widely used,but ABS is flammable and gives off a large amount of smoke during combustion,which is harmful to people’s personal and property safety.In the second part,the modified seaborne SEP₈@YS₁,which has excellent performance and good dispersion in the matrix in the first chapter,is selected as the collaborative smoke suppression flame retardant,which is combined with the expansion flame retardant system（AGT）and added to ABS resin.ABS/AGT/SEP composites were prepared.The experimental results show that with the increase of flame retardant system,the oxygen index of the material increases gradually.When the number of components is 45phr,the oxygen index of the composite material increases to 28.6%,which is 33.57%higher than that of pure ABS.In addition,in the vertical combustion test,the smoke of the material is reduced,the combustion is slow,and the self-extinguishing from the fire is realized,which passes the V-0 grade test.After cone calorimetry test,THR and PHRR of ABS/AGT45/SEP are 68.15 MJ/m² and 227.74 k W/m²,decreased by 53.3%and79.23%,respectively,compared with pure ABS.The TSP of pure ABS and ABS/AGT45/SEP were 43.52 m² and 34.66 m² respectively,and the total smoke release decreased by 20.5%.The PSPR of pure ABS is 0.24 m²/s,and the PSPR of ABS/AGT45/SEP is 0.13 m²/s,and the peak smoke release rate is reduced by 45.8%.The expansion flame retardant system and the addition of sepiolite greatly improve the flame retardant property of the material.Based on the development of seafoam-based synergistic flame retardant smoke suppressant in the first two chapters,in order to solve the problems of multiple component flame retardant systems with many processes,large side effects and poor dispersion,the third part of the work reacted APP with seafoam in the liquid phase,loaded APP into SEP,prepared the intermediate product ASP,and subsequently reacted the prepared intermediate ASP with YS,performed ASP The new well-dispersed flame retardant and smoke suppressant ASY was formed by sealing treatment,and the ABS/ASY composite was prepared by extrusion and molding method for flame retardant and smoke suppression study.The experimental results showed that the composite ABS/ASY50 achieved V-0 grade in UL-94 test,and the oxygen index of ABS/ASY50increased by 28.0%from 19.0%of pure ABS in the oxygen index test;the conical calorimetric test results showed that the composite material with 50wt%ASY flame retardant had longer ignition time,THR decreased by 14.33%and PHRR decreased by14.33%compared with pure ABS.The results of conical calorimetric test showed that the THR decreased by 14.33%,PHRR decreased by 60.16%,smoke release rate PSPR decreased by 10.31%,and total smoke release TSP decreased by 54.16%compared with pure ABS,and the inhibition of smoke release was very obvious.