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Цебренко, М. В.; Rezanova, V. G.; Tsebrenko, I. A.

doi:10.1023/a:1024760728558

Cited by 3 publications

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“…The degree of swelling B of the extrudate is an indirect characteristic of the viscoelasticity. Previous studies [9] showed that the value of B is an indirect characteristic of specific fibre formation: the more microfibres formed and the thicker they are, the higher the degree of swelling. From this point of view, we can conclude that A-300 additives improve fibre formation of polypropylene in a CPA matrix: swelling increases (Fig.…”

Section: Effect Of Aerosils On the Rheological Properties Of Pp/cpa Bmentioning

confidence: 99%

Production of polypropylene microfibres containing a filler in the nanostate

et al. 2007

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Solid nanosize Aerosil additives almost do not alter the properties of melts of PP/CPA blends. Melts of threecomponent blends are strengthened in a longitudinal velocity gradient field, manifested by a sharp increase in the maximum possible spinneret drawing. Nanosize Aerosil additives do not prevent realization of specific fibre formation in flow of melts of PP/CPA blends. As a result of stabilization of the liquid jets of PP in a CPA matrix, thinner (up to 0.30-0.15 μm) microfibres are formed with low dispersion of the distribution by diameters. This increases the specific surface area by 3-4 times. Nanofilled PP microfibres and new filter materials that combine high output and efficiency (99.999% with respect to 0.3 μm particles) were made for the first time. Aerosil additives act as crystallization centers during spinning of PP microfibres, which prevents the liquid jets from breaking down into drops. Incorporation of highly disperse Aerosils can be a method of regulating crosslinking of the polymer in the disperse phase in the matrix polymer.In the last decade, the nanostructural state of materials has been of great interest to scientists, and the research in this direction has become an important world trend. When the nanostructural state is attained, the basic functional characteristics of the materials change sharply and unique properties appear [1]. Data on the nanostate in polymers are usually limited to patent information. Polymeric nanofibres obtained primarily by electrospinning acquire unique properties: color change, ultrasound generation, reaction to specific signals, change in the pH of the medium, temperature, concentration of solutions, etc. However, solving the problems related to technical difficulties and the complexity of production of nanomaterials and the high cost of the final product remain pressing.Manufacturing nanofibres from melts of polymer blends implies reducing the diameter of the microfibres to nanosizes. One way of doing this is to add compatibilizers [2, 3], whose mechanism of action consists of decreasing the interfacial tension. By affecting interfacial events, structure formation processes can be regulated toward reducing the diameter of the microfibres. Research is also developing intensively in the polymeric nanocomposite sector, which is producing materials with unique properties [5].We investigated production of polypropylene microfibres containing a filler in the nanostate by processing melts of polymer blends. There is no published information on this topic and this research is being done for the first time.Polypropylene/copolyamide (PP/CPA) blends in the ratio of 30/70 wt. % were investigated. Industrial samples of PP and CPA were used: brand 2103016 polypropylene manufactured by Lisichansk chemical plant, brand PA-6/66-3 copolyamide manufactured by Ural Plastik IA (alcohol-soluble copolymer of 50% caprolactam and 50% hexamethylene adipate) were investigated.

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Section: Effect Of Aerosils On the Rheological Properties Of Pp/cpa Bmentioning

confidence: 99%

Production of polypropylene microfibres containing a filler in the nanostate

et al. 2007

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“…Fibre formation does not take place in the phase change region. However, macro-and microflow processes in melts of polymer blends can be controlled by adding compatibilizers (substances that improve the compatibility of the components of a blend) [2][3][4].We investigated the macro-and microflow processes in compatibilized PP/CPA blends of 50/50 wt. % composition with polyethylene glycol (PEG) additive in the amount of 0.5, 1.0, 3.0, and 5.0% of the weight of the PP.…”

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Specific Fibre Formation in Flow of Melts of Polypropylene/Copolyamide Blends in the Phase Change Region

2005

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541.64:532.135 and N. M. RezanovaThe rheological features and crosslinking processes in melts of PP/CPA [polypropylene/copolyamide] blends containing PEG [polyethylene glycol] or EVAC [ethylene-vinyl acetate copolymer]/PEG binary additive as compatibilizers were investigated. The possibility of realization of specific fibre formation was established for PP/CPA blends in the phase change region on addition of PEG as a compatibilizer. The study of decomposition of PP microfibres in compatibilized blends demonstrated a stabilizing effect on liquid jets of PP in a CPA matrix.In fabrication of ultrafine synthetic fibres by processing melts of polymer blends in certain conditions, one of the components (fibre-forming) forms a multitude of microfibres oriented in the direction of extrusion in the mass of the other (matrix) polymer under the effect of flow forces. This phenomenon is called specific fibre formation [1].We know that in polymer blends, when the ratio of components changes, phase inversion takes place; its essence is that the dispersion medium and disperse phase change roles under the effect of external factors (change in the composition of the blend, addition of a new substance, change in temperature, etc.). In polymer blends, the phase change region covers a wide range of compositions, where both phases are continuous (matrix structures). For polypropylene/copolyamide (PP/CPA) blends, the phase change region covers a 40/60, 50/50, and 60/40 wt. % ratio of components. Previous studies [1] showed that specific fibre formation is most distinctly realized for a 20-30 wt. % disperse phase content. Fibre formation does not take place in the phase change region. However, macro-and microflow processes in melts of polymer blends can be controlled by adding compatibilizers (substances that improve the compatibility of the components of a blend) [2][3][4].We investigated the macro-and microflow processes in compatibilized PP/CPA blends of 50/50 wt. % composition with polyethylene glycol (PEG) additive in the amount of 0.5, 1.0, 3.0, and 5.0% of the weight of the PP. Since [5] shows that a mixture of compatibilizers is more effective than the individual substances, we used a binary mixture of the copolymer of ethylene and vinyl acetate (EVAC)/PEG in the ratio of 0.5/0.5, 1.0/1.0, 5.0/5.0, and 10.0/3.0% of the weight of the PP. The characteristics of these polymers are reported in [6]. CPA (PA-6/66, OST 6-05-438-78) is the copolymer of caprolactam and hexamethylene adipate in the ratio of 50/50. Its melting point is close to t m of PP (brand 21060, TU 6-05-1756-78). On heating, it dissolves in ethyl alcohol, which is also used for extraction of CPA from composite extrudates to separate PP microfibres. PEG, a dihydric alcohol, has CH 2 CH 2 groups and two terminal hydroxyl groups along the length of its chain, which makes it a biphilic compatibilizer for PP/CPA blends.The polymers were blended and additives were incorporated with a LGP-25 industrial combined screw-disk extruder which finely disperses one polymer in ano...

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Extraction of nanofibers from polymer blends: A brief review

Rabiei

Kish

2018

Polymers for Advanced Techs

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This review is about the naturally formed and intentionally produced nanofibrils or nanofibers (NFs) that have been extracted and utilized or expected to be used for special applications. The diameter of NFs ranges between a few to a few hundred nanometers. Methods to arrange synthetic NFs assembly in yarns or pads forms have been examined. High throughput productions, versatility of various thermoplastics, and less environmental pollution are the advantages of the methods of extraction, which seems to make it as an economical process. It can also be used for the polymers that are difficult to be converted to NFs by electrospinning. The process is challenging and scientifically fascinating to attract the investigators. There are many more polymers to be considered, and there are many more envisioned applications that have to be practiced in the future. A theoretical base is needed for the evaluation of the effects of polymer flow parameters on the extracted NFs properties.

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Cited by 3 publications

References 6 publications

Production of polypropylene microfibres containing a filler in the nanostate

Production of polypropylene microfibres containing a filler in the nanostate

Specific Fibre Formation in Flow of Melts of Polypropylene/Copolyamide Blends in the Phase Change Region

Extraction of nanofibers from polymer blends: A brief review

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