| Dacron is the trade name of Chinese polyester fiber,and refers to the synthetic fiber which containing more than 85% polyethylene terephthalate(PET).Although the PET fiber was developed relatively late,it has a series of outstanding mechanical properties and good wash and wear property.However,as a clothing fabric,PET fiber has poor hydrophilicity,poor moisture conductivity,low biocompatibility and poor skin-friendly property.But on the other hand,the soybean protein,silkworm pupa protein and sericin protein have excellent biocompatibility,healthcare function and skin-friendly property,if the the protein with good biocompatibility could be grafted on the PET fabric,then a high-performance PET fabric with skin-friendly property and excellent mechanical properties could be produced.However,it is difficult to graft functional compounds onto the surface of PET fibers by using a cross-linking agent because the PET macro molecules have no reactive groups.Therefore,in this paper,a dilute nitric acid gradually concentrating method was investigated to nitrate and reduce PET fibers to impart PET fiber with reactive group-NH2.First,the PET fabric was immersed in a dilute nitric acid solution,then the PET fabric impregnated with dilute nitric acid was cured and the dilute nitric acid on PET fibers surfaces was gradually concentrated enough to nitrate PET to introduce-NO2,and then the nitrated PET fabric was reduced in a soudium sulfide solution to get amino reactive group.After that,soybean protein was grafted onto the PET fabric by using the self-synthesized crosslinking agent-sucrose glycidyl ether.The silkworm pupa protein(SPP)modified by epoxy chloropropane and the sericin protein modified by epoxy chloropropane were grafted on the PET fabric under a certain condition.Then a protein/PET fabric was prepared that has good biocompatibility and prominent mechanical properties.The main research contents of this paper include the process of nitration and reduction of PET fabric,the extraction process of soybean protein,silkworm pupa protein and sericin protein,the finishing process of protein,the synthesis process of crosslinking agent,the grafting processes of soybean,silkworm pupa and sericin protein,and the characterization of composite fabric after grafting protein.Research results are as follows:(1)The optimum process of nitration and reduction was as follows: dilute nitric acid concentration was 20 g/L,immersing time 10 min,bath ratio 1:30,curing temperature 70 ?,curing time 30 min;sodium sulfide 25 g/L,sodium 20 g/L,reduction temperature 98 ? and reduction time 30 min.Under these finish conditions,the contact angle of the PET fabric after nitration and reduction reduced to 0° and there were sufficient reactive groups on the nitration and reduction PET(NR PET)fabric.Scanning electron microscopy(SEM)showed that the surface of the NR PET fiber was not damaged obviously.Total reflection infrared spectroscopy and X-ray photoelectron spectroscopy showed that the amino group was endowed on the PET macromolecule chain.X-ray diffraction analysis indicated that the main structure of the NR PET fibers was well maintained.The thermogravimetric analysis showed that the thermal stability of the NR PET fiber was almost unchanged and remained well.And the crease elasticity,breaking strength and elongation of the NR PET fabric were well maintained.(2)Soybean protein was grafted onto NR PET fiber under 110 ? by using a self-made crosslinking agent-sucrose glycidyl ether to impart PET fabric with skin-friendly and hydrophilic properties.When the grafting rate of soybean protein was less than 3.48%,the contact angle of water droplets decreased below 40° in 10 s.Soybean protein/PET fabric has a good washing resistance,there was still 82.01% protein retained on the PET fiber after washing 30 times.Scanning electron microscopy showed that a layer of substance covered on the surface of soybean protein/PET fibers.Infrared spectroscopy and X-ray photoelectron spectroscopy showed that the surface of soybean protein/PET fiber contained amide and amino group.X-ray diffraction showed that the crystal structure of the soybean protein/PET fiber was kept well.The thermogravimetric analysis indicated that soybean protein/PET fibers had a good thermal stability.The crease resistance of soybean protein/PET fabric was maintained well,and the breaking strength was improved.When the soybean protein grafting rate was less than 2.44%,the hand feeling of PET fabric was still good.(3)The silkworm pupa protein treated with epoxy chloropropane under weakly alkaline condition was grafted onto the surface of NR PET fabric to prepare silkworm pupa protein/PET fabric with good biocompatibility.The washing fastness of silkworm pupa protein/PET fabric was good with a 79.2% protein retained after 60 washing times.The hydrophilicity and skin-friendly property of the silkworm pupa protein/PET fabric were improved greatly.At the same time,the rigidity and permeability were kept well,and the breaking strength increased with the increase of weight gain rate of silkworm pupa protein.The silkworm pupa protein/PET fiber was observed by scanning electron microscopy,and the images showed that the surfaces of the PET fibers were covered with a layer of material,and some materials in the gaps of fibers.The ATR-FTIR spectrum showed that the amide group appeared on the PET fiber after grafting the silkworm pupa protein.X-ray photoelectron spectroscopy showed the nitrogen content of the PET-SPP fabric was higher than that of the original PET fabric.The thermogravimetric analysis showed that the thermal stability of the PET fabric after grafting silkworm pupa protein was good,but the differential scanning calorimetry showed that the silkworm pupa protein/PET fabric had a longer melting process and a lower endothermic peak,indicating that its crystallinity has decreased.Cell proliferation test showed that the cell proliferation of silkworm pupa protein/PET fabric was 139% higher than that of original PET fabric.(4)The sericin was firstly treated with epoxy chloropropane under a weakly alkaline condition,then sericin containing with epoxy group could be firmly grafted onto the NR PET fiber under curing at 110? temperature.After washing 60 times,77.65% sericin was remaind,indicating the washing resistance of sericin/PET fabric was good.Scanning electron microscopy(SEM)revealed a layer of substance covering the surface of the PET fibers,and protein crosslinking in the gaps of fibers.X-ray diffraction analysis showed that the crystal structure of sericin/PET fiber almost did not change.Fourier transform infrared spectra revealed that the sericin was grafted on the PET fabric surface due to the new characteristic peak of protein.The X-ray photoelectron spectroscopy showed that new nitrogen element appeared on the PET fibers after grafting sericin.Differential scanning calorimetry(DSC)measurements suggested that only the PET fiber surface was modified,the thermal behavior was maintained.The mechanical properties such as breaking strength,crease elasticity and stiffness of sericin/PET composite fabric were good and the hydrophilicity was improved greatly. |
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