Preparation And Study On Properties Of FRPET Containing Intumescent Flame Retardants

In this study,two charring agents tris(2-hydroxyethyl)isocyanurate terephthalic acid ester(T-ester43 and T-ester45)with different degree of esterification were synthesized by using tris(2-hydrooxyethyl)isocyanurate(THEIC)and purified terephthalic acid(PTA)as raw materials.Two kinds of intumescent flame retardants(IFR43 and IFR45)were prepared via combination of T-ester and ammonium polyphosphate(APP).The preformed IFR were melt blended into four commercial thermoplastics(PA6,PET,PLLA,PP),respectively,and to obtain phosphorus-containing flame retardant polyethylene terephthlate(FRPET).The chemical structure,thermal properties,combustion performance and anti-dripping property were characterized by means of Fourier transformed infrared spectrometry,~1H-NMR spectrumetry,differential scanning calorimetry,thermogravimetry,limiting oxygen index instrument and cone calorimetry.The results showed that the decomposition temperature of charring agent increased up to300℃after esterification,and char residue at 700℃to 10%from 1%of neat THEIC.The LOI value of polymers after loading of 20 wt%IFR43 was enhanced by 6%～7%,as well as the melt drops decreasing.From the overall point of view of flame retardancy,IFR43 showed better performance than IFR45.In addition,an obvious crystallization acceleration effect was found in the sample of PLLA after addition of IFR.FRPET with 20 wt%of IFR(in that,APP/T-ester=17:3,wt%)can achieved the optimal flame retardancy.The char residue of FRPET/IFR17-3 at 700℃is 23.2%,and the LOI value increased to 32～33%.The numbers of melt drops fell to 28(average)from 44(average)in per minute.The peak heat release rate and peak smoke releate rate decreased by 46.4%and 59.2%,respectively.Moreover,a continuous and expansionable char layer formed after the completion of combustion in CONE tests.The flame retardant effect of IFR on FRPET increased with increasing the loadings of IFR.