| Nowadays with the improvement of people’s living standard, the moisture absorption and ventilation、wearing comfortable clothes has become a great concern. Cellulose Diacetate(CDA) fiber has much advantages of neat, comfortable and bright luster. However its low fracture strength has limited the application in taking areas. The conventional polyacrylonitrile fiber(PAN), with the honor of “artificial wool”, was the customer’s favorite with the low price and excellent performance. Due to the special structure of PAN, so it has the disadvantages of poor moisture absorption, easy to static electricity and so on. Therefore, considering about the advantages and disadvantages of above two kinds of fibers, this paper mixed the CDA and PAN to spin the excellent CDA/PAN blend fiber. Then the homemade blend fiber was treated by NaOH solution to further improve the hygroscopicity. This hydrophilic fiber with a certain strength can expand the application in the field of clothing.The rheological properties of CDA/PAN solution are found: the steady state test results showed that the CDA/PAN solution system is a non-Newtonian fluid. The non-Newtonian index was increased with the increasing of PAN content or the decreasing temperature of the solution, and the viscous flow activation energy was also increased. When the content of CDA/PAN is constant, the viscous flow activation energy was decreased as the shearing rate is increased. So when the content of PAN was higher, an appropriate shearing rate increasing can reduce the influence of temperature change, in order to reduce processing difficulty. Dynamic test results showed that the storage modulus value G’ and loss modulus value G’’ of the CDA/PAN system was increased with the increasing of shearing rate. And the intersection of G’ and G’’ moved in the direction of higher shearing rate with the increase of temperature. When the shearing rate in range of 0.1~100 rad/s, most of the CDA/PAN solution under different temperature presented a G’<G’’ curve relationship, showing viscous properties, namely the spinnability of the blend solution was good, especially choosing the spinning temperature as 60℃, spinnability could be better.The CDA/PAN blend solution with different ratio was selected to wet spinning at room temperature. Through the control of the spinning process, the optimum spinning process was obtained: the temperature of coagulation bath was 40℃, and the concentration was 60%, while the jet stretch ratio was 0.9, and the first water bath draft ratio was 1.5 times, in the second boiling water drawn, the maximum CDA/PAN draw ratio was 4 times. In this process, the maximum fracture strength of the blend fiber was 2.55cN/dtex, the crystallinity was 41.78% and the orientation degree is 0.791, which meet the requirement of conventional fiber.Through the adjustment of the hydrolysis process of the blend fiber, the optimal hydrolysis process was obtained: the hydrolysis temperature was 90℃, hydrolysis time was 12 min, the concentration of NaOH was 15%, and bath ratio was 15:1. In this process, the surface roughness of the fiber was increased, the cross section become loose, and the permeability of water molecules and dye molecules was increased. After hydrolysis carboxyl, amide groups and water molecules could form a hydrogen bond, meanwhile the binding force of the dye molecules was enhanced, so that the water absorption of the blend fiber increased by 3~4 times, the dying rate increase by 2%~6%. So the hydrophilic experiment of the CDA/PAN blend fiber has important practical significance.The above research showed that CDA/PAN blend fiber was expected to become a new generation of taking fiber and improve the shortcomings of traditional fiber. This excellent fiber could provide people with a more comfortable dressing experience. |
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