Study on Rheological Behavior of Polypropylene Modified by PEG, EVA and WSPET Jiang Tao (Shenyang University of Technology, Liaoyang 111003, Liaoning, China) The rheological behavior of polypropylene modified by PEG, EVA and WSPET blends. The study found that the blended PEG decreased the apparent viscosity of the modified PP, but the extrusion increased. The apparent viscosity of the modified PP first decreased and then increased with the increase of the amount of EVA added; the addition of WSPET made the modified PP. The apparent viscosity decreased; at the addition of about 10%, all three modifiers decreased the apparent viscosity of the modified polypropylene, with WSPET being the most significant.
Polypropylene fiber has the advantages of small density, high strength, good warmth retention, chemical resistance resistance, good electrical insulation, and convenient processing and molding. It has become one of the most promising synthetic fibers of today. Due to the excellent properties of polypropylene fiber, it has a huge market in the three fields of decoration, engineering, and clothing. Therefore, the development of polypropylene fiber, the development of new varieties of polypropylene fiber, and the expansion of the application of polypropylene fiber are important in the world today. Research topics. However, due to its regular structure and high crystallinity, polypropylene has no polar groups, making it dyeable, adhesive, antistatic, hygroscopic, and compatible with other polar polymers, inorganic fillers, and metals. The adhesiveness is very poor, limiting the entry of polypropylene fibers to 10?09: Jiang Tao (1957?), male, associate professor of Liaoning Jinzhou.
One step promotion 1. In order to improve the performance of perspiration, moisture permeability and other clothing, the current work on the modification of polypropylene to obtain a highly hygroscopic polypropylene fiber with a high moisture-absorbing polypropylene is becoming a hot topic, and the research focuses mainly on fine denier and super Fine denier spinning technology development, surface hydrophilic treatment, chemical graft modification and blend modification are among these aspects, in which blending modification technology is one of the effective ways to obtain polymer materials with excellent overall performance. Studies have found that in the polypropylene, the hygroscopicity of the prepared polypropylene fiber after blending a certain amount of polar polymers such as polyethylene glycol (PEG), ethylene vinyl acetate copolymer (EVA), water soluble polyester (WSPET) There is a clear improvement. This is because when the PP matrix is ​​mixed with other components with polar groups, the amorphous region is enlarged, the regularity of the PP fiber structure is destroyed, and the hygroscopicity is improved; some of the blended components are soluble in the alkali solution. On the surface and inside of the fiber, numerous micropores are formed, and PP fibers with micropores have good hygroscopicity; and the introduction of polar groups also plays an important role in improving the hygroscopicity. The addition of blending components that are not completely compatible with the PP matrix also changes the mechanical behavior and spinnability of the polypropylene.
In order to solve the processing problem of hygroscopic polypropylene, this paper focuses on the rheological behavior of polypropylene modified by PEG, EVA and WSPET blends. Because the apparent viscosity is important for the spinnability, this article focuses on the effect of PEG, EVA, and WSPET on the apparent viscosity of the modified polypropylene, with a view to helping the research and development of high moisture-absorbing polypropylene.
It can be seen that the EVA-modified polypropylene system decreases with the increasing temperature of D, and the PP-like sample is a pseudoplastic fluid with shear thinning phenomenon.
2.2.2 Effect of EVA mass fraction on n At 190, 250 C, the effect of EVA mass fraction on melt n is shown in Table 4. From and 4 are visible. The mass fraction of EVA has a great influence on the melt n, and it increases at 250 hours. With the addition of EVA, the melt n first decreases and then gradually increases. When the mass fraction of EVA is 11%, each n is close to the pure polypropylene, and when the EVA mass fraction continues to increase, n continues to increase, and each EVA mass fraction is 30%. The lower n is significantly higher than that of pure polypropylene. This is because EVA has a certain degree of cross-linking and can form a network through cross-linking chains. When the mass fraction of EVA is low, PP is used as a continuous phase to enclose EVA inside, so that the viscosity of the entire system is decreased; when the mass fraction of EVA is gradually larger, the blend of EVA and PP forms a matrix-like microfiber structure. EVA is uniformly dispersed in the continuous PP phase. This network structure inhibits the activity of the continuous phase and increases the flow resistance of the system. Therefore, the viscosity of the PP/EVA system varies with the mass fraction of EVA.
In general, n does not change much with the WSPET mass fraction; however, at WSPET, the WSPET melts completely and the molecular weight of the WSPET melt acts like a plasticizer. As with the PEG, the melt flows around the PP. The phenomenon of knots is reduced, the displacement unit becomes smaller, the flow resistance decreases, and n decreases; WSPET has a large mass fraction and n gradually decreases.
The effects of PEG, EVA, and WSPET on the blending system n can be seen. When the adding amount is about 10%, the addition of PEG, EVA, and WSPET both lowers n. Among them, WSPET has the most significant effect. This is because WSPET is a mixed copolyester of benzenes and meta-benzenes. Its molecular chain is rigid and has a large intermolecular force. It is a kind of “temperature-sensitive†polymer. Its temperature increases and its apparent viscosity decreases. Faster, combined with the low molecular weight of WSPET, the molecular mass distribution and melting range are very wide, so the maximum reduction is at 250 degrees.
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