Study On The Preparation And Structure Properties Of Polyamide Ester And Fibre Based On PA6/PET

Polyethylene terephthalate(PET)fibers and polyamide 6(PA6)fibers are two of the world's largest synthetic fibers.Polyester has high molecular modulus,so the fabric is anti-wrinkle but has a harder hand.As a fabric,poor hygroscopicity of polyester is prone to static electricity and sweltering;Whlie polyamide has good hygroscopicity due to the hydrophilic group of molecules.However,polyamide also has disadvantages of low modulus,poor dimensional stability,After comparison,it is found that the advantages and disadvantages of the two materials can be complementary to each other.In order to obtain a material having both excellent characteristics of them,this article provides a method for preparing high-performance polyamide ester fiber by a chain-exchanging reaction of prepolymers.Firstly,polyamide prepolymer was prepared.During caprolactam hydrolysis,excess dibasic acid was added for capping,and double-blocked with ethylene glycol to prepare one of the prepolymers of the polyamide ester,named esterified polyamide(esterified prePA6).And then esterifying the terephthalic acid and hexanediol to prepare PET prepolymer-BHET.Finally,the polyamide ester was obtained by the polycondensation and chain-exchange reaction of the esterified prePA6 and BHET and its oligomers,along with the removal of ethylene glycol to achieve chain growth.Polyamide ester fibers were successfully prepared by spinning,and the properties of the obtained fibers were studied.The main conclusions obtained are as follows:(1)The prepolymers and esterification methods provided in this study can effectively shorten the reaction time,which is helpful to increase productivity,and successfully prepare a uniform and stable copolymer-polyamide ester.(2)The DMA analysis of PEA shows,there is only one glass transition temperature(Tg)in PEA,and the DSC carves also have only one crystallization peak and one melting peak.All of these prove that the prepared PEA is a polymer,not a two-phase separation blend.According to the analysis of TGA and SEM,PEA obtained by polymerization is a polymer with good thermal stability and compatibility and high uniformity.Meanwhile combining the nuclear magnetic proton spectrum and infrared characterization of PEA,it's fully proved that the polyamide ester obtained by polymerization was a chain-exchange reaction between PA6 and PET components to form copolymers,and the response rate of CPL is 80%~93.3%.The GPC results of PEA slices show that the increase of PA6 components is not conducive to the increase of the molecular weight of the polymer.The molar ratio of CPL to PTA up to the spinning grade of PEA can be up to 0.2:1.(3)The properties of PEA fibers were characterized,The analysis of the moisture regain of PEA fiber shows that the increase of PA6 component contributes to the increase of moisture regain of polyamide ester fiber.PEA-PA6-20% even doubled the resurgence of PET to 0.835%,which is taken as a reflection of good moisture absorption performance.Therefore,the hygroscopicity of PEA fibers is higher than that of PET.The mechanical analysis of PEA fiber shows that the addition of PA6 component makes the modulus(14.7~59.5 cN/dtex)and breaking strength(1.4~3.7 cN/dtex)of polyamide ester fiber decrease,and the elongation at break(19.9~73.6%)improve.In clothing fibers,the decrease of the initial modulus will make the textile more soft and comfortable.