Preparation And Properties Of Intrinsic Flame Retardant Nylon 66

Nylon 66(PA66)possess excellent comprehensive performance,which was mainly used in electronic,instrumentation,autombile,aerospace and so on.However,the applications field of PA66 were confined by its flammability.Therefore,it is necessary to improve their flame retardant to meet the industrial safety standards.In general,the additive flame retardants are applied to enhance the flame retardant and thermal stability of PA66,which is always presence of some issues including the high addition amount,poor compatibility with matrix,and influence the mechnical property of PA66.Therefor,a kind of reactive flame retardantand with expansion character was synthesized and connected to the main chain of nylon 66 for the preparation of intrinsic flame retardant PA66 by polymerization.The resultant intrinsic flame retardant PA66 presents good flame retardant and mechanical performance because the flame retardant unit was covalently the polymer backb one.(1)A flame retardant named as 2-(dimethyl phosphate)-4,6(2-hydroxyl propionic acid)–isotriazine was synthesized from chloride(TCT),trimethyl phosphate(TMP)and 2-hydroxyl propionic acid(HP),which is a new reactive flame retardant with the P and N elements.The results of FTIR,element analysis,melting point apparatus,and TGA show that the reactive flame retardant possesses of high purity,260~oC of initial degradation temperature,which could meet the polymerization condition of PA66.Meanwhile,the reactive flame retardant displays outstanding char formation.The carbon rate is 18 per cent.(2)The flame-retardant nylon 66 was prepared by polycondensation of nylon66 salt(PA66 salt)and flame retardant salt that based on 2-(dimethyl phosphate)-4,6(2-hydroxyl propionic acid)–isotriazine and hexamethylenediamine.The FTIR results show that the flame retardant has been successfully connected to the main chain of nylon 66.The phosphorus content of IFR-PA66 was measured by Element analysis method.The results show that the phosphorus content is 0.556%when 8 wt%flame retardant salt was introduced into the PA66,which is close to the theory value of phosphorus content.(3)The results of flame retardant properties of IFR-PA66 show that the LOI value and the rate of UL-94 reached 32 and V-0 with the increase of reactive fire retardant.The data of TG and DSC present that the melting temperature and glass transition temperature of the IFR-PA66(253~oC,205~oC)are lower that of the pristine PA66(265~oC and 228~oC).With the introduction of the reactive fire retardant,the highest thermal degragation temperature of IFR-PA66 was raised to 470~oC.In addition,the IFR-PA66 exhibits good mechanical properties though a certaion amount of reactive fire retardant was introduced into the PA66 matrix.