Preparation And Properties Of Copolymerized Flame-retardant PET Fibers

At present,polyethylene terephthalate(PET)fiber is the largest synthetic fiber in the word.PET fiber has good properties,and its textiles is accepted in many fields,including clothing,home textiles,industrial textiles.However,PET h is a flammable material.and it causes great harm when burning.So flame retardant modification of PET is very necessary and urgent.At the beginning,this paper summarizes the research and development of flame retardant technology,and then synthesizes a series of flame retardant PET copolyesters by copolymerization.And studied the performance and internal relations of various aspects of polymers,fibers,and fabrics,hoping to provide theoretical support for the wide application of flame-retardant PET fibers.The main research achievements are as follows:1.The flame-retardant PET copolyester was synthesized by esterification and polycondensation reaction.With the increase in the feed ratio of the flame retardant 2-Carboxyethyl(phenyl)phosphinicacid(CEPPA),the polycondensation reaction becomes slower.~1H-NMR,FTIR and ICP test results show that the flame retardant monomer CEPPA is bound to the PET macromolecular chain by copolymerization.The intrinsic viscosity of the synthesized copolyester is 0.607?0.650 d L/g,and the melt index is 33.52?70.17 cm~3/10min,which meets the spinning standard.DSC test results show that the Tg,Tm and C of copolyesters decrease with the increase of CEPPA feed ratio.Thermo Gravimetric Analyzer(TGA)test results show that under air atmosphere,the higher the feed ratio of CEPPA,the more residual carbon and the T_5%of the copolyester is higher than 374?,Which is much higher than the spinning temperature of the fiber,and has no major impact on fiber formation and subsequent textile processing.The flame retardant PET copolyester's combustion performance test results show that he LOI and UL-94 of the copolyester reaches flame retardant grade and V-0 when the addition of CEPPA is 6 mol%(the molar ratio of CEPPA to PTA),t.Cone calorimeter test results show that copolyester can effectively reduce heat release,and there are gas and solidified phase flame retardant during the combustion process.The isothermal crystallization properties of flame-retardant PET copolyesters were studied using DSC.It shows that flame-retardant PET copolyesters tend to nucleate heterogeneously,and the crystal growth method is three-dimensional spherulitic growth.Polarizing Optical Microscope(POM)test results verify this conclusion well.Since the isothermal crystallization process is affected by many factors(mainly including the"plasticization","dilution"and nucleation effects of CEPPA on the copolyester),with the increase of CEPPA feed ratio,the crystallization rate of copolyester increases,decreases,and then increases.3.Select flame-retardant PET copolyester with a CEPPA content of 8 mol%for melt spinning.Compared with PET fiber,its crystallinity and orientation decreases,while the boiling water shrinkage rate and the moisture regain rate increases.The breaking strength of flame-retardant PET fiber has been reduced,but the mechanical properties can still meet the weaving requirements.Flame-retardant PET fiber has good flame-retardant properties and can self-extinguish quickly after being ignited in the air.4.The flame retardant PET fabric was woven by a small prototype,and under normal temperature and normal pressure dyeing conditions were investigated..When the dyeing rate of flame-retardant PET fabric is the highest,the mass fractions of disperse red,disperse yellow,and disperse blue are 3 wt%,2 wt%,and 3 wt%,respectively.The higher the dye mass fraction,the higher the K/S value of the fabric,so the fabric can be dyed deep colors under high dye mass fraction.Through process optimization,the dyeing effect of flame-retardant PET fabric is better under 100?,60 min and p H=5.These research results show that,different from the high-temperature and high-pressure dyeing of PET fabrics,flame-retardant PET fabrics can achieve better dyeing effects under the conditions of low-temperature boiling dyeing.By analyzing the flame-retardant properties of fabrics before and after dyeing,it can be found that the vertical combustion performance of flame-retardant PET fabrics after dyeing is reduced to a certain extent,which indicates that the selection of dyeing process damages to the flame retardancy of fabrics,which needs to be studied in subsequent studies.