Study On The Preparation And Properties Of Polyester Fibers Modified By Natural Polymers

Polyester has been applied in various fields including textile,industrial,medical and so on for its excellent mechanical properties and mechanical properties.However,high degree of crystallinity and lack of polar groups make PET has poor hydrophilic performance and antistatic property.Therefore,it is essential to solve these problems and prepare multi-functional polyester fibers.At present,there is still a certain gap in the overall level and quality compared with the foreign countries and Taiwan area.In general,there is great room for domestic polyester industry to improve the differentiation rate of polyester products.Therefore,sucrose ester（SE）was used to fixed on the surface of PET fiber to improve the activity on the base of alkali treatment in this project.Furthermore,chitosan and alginate were applied to coated on the surface of PET fiber and the hydrophilicity,antistatic and antibacterial properties got improved.Firstly,ethylene glycol / water mixture was used as solvent for alkali treatment of polyester fibers and the orthogonal experiment was applied to study the effects of various reaction conditions on the reduction rate of polyester fiber.Also,sucrose ester（SE）was used to fixed on the fiber surface in the condition of high temperature and high pressure.The chemical structural of polyester fiber before and after the treatment was characterized by infrared spectroscopy（IR）and morphological analysis（SEM）.What’s more,we studied the impacts of reduction rate on mechanical properties,thermodynamic properties as well as sucrose ester fixation rate of polyester fiber and chose the optimum processing conditions in final.The results showed that alkali treatment has certain influence on the mechanical properties of polyester fiber where yarn density,fracture strength and elongation all decreased in varying degrees.In the situation of reduction rate reaching 23.21%,the breaking intensity decreased from 2.83 c N/dtex to 4.21 c N/dtex.When the reduction rate is less than 15%,the fixation rate of SE increases with the reduction rate;while the reduction rate exceeds 15%,the fixation rate shows a decreasing tendency.So,the optimum reduction rate is among 10%¹5%.It should be noted that after treated by SE,the surface of polyester fiber is covered with a thin and dense layer,and with the increase of SE concentration,the layer comes to be obvious and thicker.In addition,the fiber has a lower fixation rate and higher retention rate with a low concentration of SE;however,with the increasing of SE concentration,the fixation rate increased.Secondly,alginate was coated on the surface of polyester fiber using sol gel method and silver ions were loaded on the fiber by ion exchange.The modified fiber is characterized by infrared absorption spectroscopy（IR）,X ray photoelectron spectroscopy（XPS）and morphological analysis（SEM）.Thermal stability,mechanical properties hydrophilic and antistatic properties were also tested.Moreover,we studied the effects of silver ions with different concentration on the antibacterial performance and determined the optimum treatment conditions.The results show that the surface morphology and chemical structure of polyester fibers have changed after modification and the number of hydroxyl groups increased.What’s more,with the increasing concentration of alginate,the coating deposited on the fiber became thicker.Compared with untreated fiber,the fineness of the modified polyester fiber increased slightly while the mechanical properties and thermodynamic properties were not affected obviously.Also,the hydrophilic and antistatic property of treated fibers have further improved where the contact angle decreased from 122°to 54°and the half-life reduced from 150 s to 20 s.After ion exchanging with Ag+,polyester fibers have a significant inhibitory effect on Escherichia coli and keep good antibacterial property even at low concentrations.Considering the balance among the antibacterial effect,the loss rate and safety,the concentration of 0.005mmol/L Ag NO3 was chosen for ion exchanging where the silver content in the fiber is 35μg/g.Finally,chitosan-CO₂ solution was prepared for the preparation of chitosan / polyester fibers（CS/PET）by sol-gel method.A series of tests were carried out to characterize the mechanical properties,moisture regain rate,antistatic properties and crystallization properties of the modified fiber.The results indicated that polyester fibers treated by chitosan with different concentrations have different degree of improvement in moisture regain and antistatic property compared to the initial fibers.In the situation of treated by 2.0wt% chitosan,the moisture regain increased by 3.4 times and the half-life decreased from 150s to 25s.