Study On Hydrophilic Finishing Of Polyester Fabric

Hydrophilic modification of polyester（PET）fabric is one of the key points in the field of artificial fiber.In order to obtain good effect,this paper uses a variety of methods to modify PET hydrophilic.Both of Sericin and acrylic acid have good hydrophilic properties.It is possible to obtain the expected composite PET hydrophilic material by grafting on surface while maintaining physical properties.But it is difficult to carry out chemical grafting directly on the surface due to a little reactive groups in the macromolecular structure of PET.Therefore,amino groups were contacted on the surface of PET to produce amino polyester（NR PET）by optimized nitration and reduction methods in this paper.The hydrophilic PET materials were prepared with boric acid as a crosslinking agent by one-step and two-step methods.AA monomer was grafted on the surface of PET by chemical method using different initiators to prepare PET fabric with good hydrophilicity and mechanical properties.Through the research on the grafting process of reaction and the structure performance of product,the main conclusions were as follows:（1）The nitrifying PET fabric was prepared with nitric acid,and then it was reduced to NR PET.The optimum conditions of nitrifying PET fabric were as follows:the concentration of nitric acid 25 g/L,the reaction temperature 80^oC,the reaction time 40min,and the bath ratio 1:30,then NR PET was obtained by reducing method with sodium sulfide.After nitrification and reduction treatment,the amino content on PET was 1.48×10^-5 mol/g.The results of FTIR,EDS,hydrophilicity test and dyeing analysis showed that the hydrophilic amino groups were introduced onto PET after nitrification and reduction reaction,and its hydrophilicity and dyeing property were improved.The results of XRD and SEM showed that the crystallization peaks and morphology of PET were almost unchanged.According to the mechanical properties test,the breaking strength was decreased and the elongation at break was increased after the reduction of nitrifying PET fabric.（2）The optimum technological conditions of one-step method were as follows:the mass ratio of boric acid to sericin 1:30,sericin concentration 8wt%,reaction temperature 60^oC,bath ratio 1:50.The optimum technological conditions of two-step method were as follows:boric acid concentration 0.5wt%,reaction temperature of boric acid 60^oC,the bath ratio of boric acid is 1:50,sericin concentration 4wt%,reaction temperature of sericin 80^oC and the bath ratio of sericin 1:50.By infrared spectroscopy and EDS analysis,it was confirmed that both sericin could be immobilized on NR PET with one-step and two-step methods.XRD and DSC analysis showed good thermodynamic properties after grafting sericin.The mechanical properties test showed that the breaking strength of PET fabric grafted with sericin did not change much.SEM showed that the main structure of PET fiber grafted sericin was not destroyed,the surface of PET fiber was covered with a layer of material.（3）AA was used as hydrophilic monomer and grafted on NR PET with KMnO₄,Irgacure 2959 and azodiisobutyronitrile as initiators.These optimum conditions of three initiators were obtained.The optimum grafting conditions with KMnO₄ as initiator were as follows:initiator concentration 2 wt%,reaction temperature 60^oC,reaction time 4 h,AA concentration 20 wt%.The optimum grafting conditions with Irgacure 2959 as initiator were as follows:initiator concentration 4 wt%,reaction time1 h,AA concentration 10 wt%.The optimum grafting conditions with azodiisobutyronitrile as initiator were as follows:initiator concentration 0.493 wt%,reaction temperature 95 ^oC,reaction time 1 h and AA concentration 3.6 wt%.The dyeing rates of PET fabric grafted with PAA using Irgacure 2959,KMnO₄ and azodiisobutyronitrile as initiators were respectively 73.77%,75.06%and 18.51%.The modified fabric modified with Irgacure 2959 and KMnO₄ as initiators had good dyeing property and high color fastness.The results of FTIR analysis showed that AA could be immobilize onto NR PET using all three initiators.XRD and DSC analysis showed that the PET had no significant effect on the crystal structure and thermal properties of the fabric.SEM analysis showed that there was no damage to the structure of PET after grafting PAA,the surface was covered with a layer of substance.The mechanical properties of the fabric show that the fabric has good mechanical properties.