Synthesis Of Novel Phosphorus-silicon Based Flame Retardants And Study Of Their Flame Retardancy Properties

Phosphorus silicon flame retardant is composite flame retardant,which contain phosphorus,silicon as main components.It has been widely used in electronic appliances,aviation industry,construction industry,transportation,household items,and so on.In this paper,a series of novel phosphosilicone flame retardants were synthesized from phosphorus oxychloride,pentaerythritol and various chlorosilanes.Their properties and application containing in polyhexamethylene adipamide(PA66)were studied.This paper mainly includes the following contents.(1)A series of novel phosphosilicone flame retardants based on 1-oxyl-phospha-4-hydr-oxymethyl-2,6,7-trioxabicyclo[2.2.2]octane(PEPA)were prepared.During the process of synthesizing intermediate PEPA,ultrasonic technology has been introduced to explore the effect of ultrasonic conditions,such as reaction time,reaction temperature and yield.The results showed that the introduction of ultrasound significantly reduced the time and temperature of synthesizing PEPA,and increased the yield of the reaction.(2)A series of phosphosilicone flame retardants tetra-(1-oxo-2,6,7-trioxa-l-phosphabi-c yclo-[2.2.2]-octane-4-methyleneoxy)silane(TPSi)and tri-(1-oxo-2,6,7-trioxa-l-phosphabicy clo-[2.2.2]-octane-4-methyleneoxy)phenylsilane(PPSi)were synthesized.The effects of reaction temperature,dropping temperature of silicon tetrachloride,choice of solvent and the choice of acid-binding agent on the reaction yield were discussed by single factor experiments.The intermediate PDCP was prepared by the reaction of PEPA with phosphorus oxychloride.Then PDCP and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were used as the main raw materials to synthesis a new type of polymeric flame retardant PNSFR,which contained three kinds of flame retardant elements,such as phosphorus,nitrogen and silicon.Through the design of orthogonal experiment,the optimal conditions of synthesizing process was determined and the flame retardancy was tested.(3)The thermal stability of phosphosilicone flame retardants was obtained by thermogravimertic analysis.The initial decomposition temperature and carbon residue of the three kinds of flame retardants were also abtained.Using the high temperature muffle furnace calcination experiments determined the charcoal capacity of flame retardant PNSFR after heating.The excellent performance of phosphorus silicon flame retardants were screened out by comparing each other.Besides,the synergistic effects of phosphorus,silicon and carbon on their flame retardancy were also discussed.(4)The three kinds of the prepared phosphorus-silicon flame retardants were mixed with PA66 for different proportions.After mading the standard spline of PA66,oxygen index,flame retardant efficiency,total combustion time,total smoke release,Izod notched impact Strength,tensile strength and other properties were measured.The effects of three kinds of flame retardants on the flame retardancy and mechanical properties of PA66 were analyzed.The regular pattern was concluded and the best adding amount of flame retardants was obtained.This study would be guidance for actual production and application of phosphorus silicon flame retardant in future.