The Preparation Of Flame Retardant PA6/flame Retardant PET And Their Composite Fiber

In this paper,pentaerythritol phosphate alcohol(PEPA),zinc diethyl phosphate(ZDP),were selected as flame retardants to prepare PA6/ PEPA,PA6/ PEPA/ZDP,PET/ZDP flame retardant blends,respectively.The morphological structure of the blends was characterized by scanning electron microscope.The flame retardant performance of flame retardant systems were characterized by limit oxygen index,vertical combustion and conical calorimetry.The thermal transformation,thermal decomposition and crystallization of the blends were analyzed by means of differential scanning calorimetry,thermal loss and two-dimensional X-ray diffraction.The flame retardant mechanism was also explored by infrared spectrμm and TG-FTIR.And based on this,the flame retardant PA6 as the cortex,the early stage of the research of preparation of flame retardant PET / 2-carboxyethyl phenyl phosphinic acid(CEPPA)as the core layer,then the sheath-core composite fiber of flame retardant PA6 / PET were prepared by double-screw spinning machine.Then the mechanical properties of the fibers were characterized.The results showed that when PEPA was added by 30 wt% in PA6 matrix,the LOI reached38 % and the flame rating was V-2,but the thermal stability of PA6 was decreased.However the ZDP can effectively improve the thermal stability of PA6/ PEPA.When PEPA: ZDP was 10:5,the LOI can reach 28 %,and.the mean heat release rate and total heat release decreased by 34.5 %and 30.8 % compared with pure PA6,respectively,which indicated that synergistic flame-retarding function existed between PEPA and ZDP.The dispersion of ZDP in PET was better than PA6.When the contents of ZDP in PET reached 5 wt%,the cone calorimeter carbon residue contents of blend increased by 229 %,the mean heat release rate and total heat release decreased by 97.5 % and 27.9 % respectively compared with pure PET,and there had less impact on the thermal stability of PET.When the contents of ZDP was 10 wt%,the LOI reached 30 %and the flame retardant grade was V-0.Composite spinning test showed that using the PET/CEPPA as the core layer,PA6 and PA6 / PEPA(content of PEPA was 10 wt %)and PA6 /PEPA / ZDP(PEPA: ZDP was 10:5)for the cortex,three composite fibers were prepared with sheath-core ratio of 50 / 50,which had certain guiding significance.