Preparation And Properties Of Bio-based Polyamide 56 Modified Polyester Fibers

PET fiber belongs to synthetic fiber.The production cost of the fiber is low.At the same time,it has the advantages of heat resistance,corrosion resistance,lighe resi-istance etc.The fabr-ics have a good shape retention,fastness and durability.However,fibers also have disadvantages.PET fibers have poor hydrophilic and cannot be dyed by conventional dyeing,and have poor anti-static properties.Polyamide fiber(PA)a-has amide bonds in the main chain,amide group belong-s to hydrophilic group,and the mide bond can also form a hydrogen bond with water,so the poly-amide fiber has very good hydrophilic,while the main contains a lot of flexible methylene so pol-yamide fiber has good strength and softness.If a new type of polyamide ester fiber is produced,w-hich has the advantages of both polyester fiber and polyamide fiber,the future market for this fiber will be even broader.The main research content of this project is to use the direct esterification method to ma-ke terephthalate(PTA)and ethylene glycol(EG)react to obtain polyester,and using the polyamid-e 56 oligomer to modify at different stages of polyester synthesis.By changing the reaction condi-tions to synthesis two series of new polyamide ester,while the new polyamide ester fiber by melt pinning method.Polyamide ester chips and fibers are tested for structure and performance by som-e test methods.Research shows,1.Through the study of infrared spectroscopy(FT-IR)of two series of new poly-amide ester chips,it is proved that polyamide 56 oligomers are successfully introduc-ed into the macro-molecule chain of the polyester,and then the polymer was further subjected to nuclear magnetic r-esonance.The structure of the polymer was characterized by ¹H-NMR and ¹³C-NMR.Studies hav-e shown that polyamide 56 oligomers have successfully participated in the reaction and added to t-he polyester on the main chain.2.One-dimensional wide-angle X-ray diffraction(WXAD)analysis is performed on the new polyamide ester samples.WAXD analysis of the novel polyamide esters show that the crysta-lline structure of the novel polyamide esters is still typical of polys-ter crystal structure.At the s-ame time,studies have shown that the degree of crystalli-nity decreases from 32.69%to 25.26%.3.Through static contact angle(CA)study of two series of new polyamide ester chips,the static contact angle are between 65.8 and 78.0°.Viscometer is used to test the intrinsic visco-sity of the slices.The intrinsic viscosities are between 0.60 and 0.80 d L/g,and the viscosity ave-rage molecular weight calculated from the viscosity was above 16,000,which are suitable for spi-nning.4.By studying the thermal properties of polyamide ester chips,Founding that with the increase of polyamide 56 oligomer content,the melting point of the new polya-mide ester grad-ually decreased between 235.80 and 221.33°C,and the glass transitio-n temperature are also Bet-ween 76.15 and 71.89 degrees Celsius gradually decreased.Thermal gravimetric(TG)tests are pe-rformed on the new polyamide ester chips.The analysis show that the initial decomposition point temperatures of the samples are all above 340^oC,and that the series 2 temperature was higher at the same percentage of weight loss.5.The UDI-DT process route was used to prepare new polyamide ester fibers.T-he UD-Y draw ratios were 3.3,3.7,and 4.0 times respectively.By analyzing the crystallization of the fila-ments,the degree of orientation and draw ratio of the sample fil-aments were shown.There was a positive relationship between the crystallinity between 11.3 and 26.6%.At the same time,the orie-ntation degree of the filaments was also positively correlated with the draft ratio.The degree of or-ientation is between 0.62 and 0.81.6.The moisture regain of the sample filaments are tested.Analysis show that the moi-sture regain of the filaments increased with the increase of the LPA56 monomer c-ontent.When the addition amount is only 5%,the moisture regain could be achieved.Above 1.0%and above,w-hen the polyamide 56 monomer content reaches 15%,the moisture regain can reach 1.56%.7.The boiling water shrinkage test of the filaments shows that there is a positive relatio-nship between the boiling water shrinkage and the filament draft multiple.The tensile properties of the sample filaments were tested and the results showed that there was a positive relationship b-etween the breaking strength of the filaments and the initial modulus,and the relationship between the elongation at break and the multiples of the filaments was inversely proportional.At the same time,as the addition of polymide 56 oligomers increases,the relationship between the breaking st-rength,initial modulus and elongation at break of the novel polyamide ester filaments is reversed,the in-itial modulus,breaking strength decreases,and the elongation at break decreases.The incr-ease in the rate indicates that as the monomer is added,the softness of the filament is improved,but the mechanical properties are decreased.