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Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution./
Author:	Joghataei, Majid.
Description:	1 online resource (204 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-10, Section: B.
Contained By:	Dissertations Abstracts International84-10B.
Subject:	Skewness. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30364031click for full text (PQDT)
ISBN:	9798377684077

Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution.
Joghataei, Majid.

Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution. - 1 online resource (204 pages)

Source: Dissertations Abstracts International, Volume: 84-10, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2023.

Includes bibliographical references

Meltblowing technology is one of the most economical ways to produce fine fiber webs. Properties and quality of web, fiber size, and fiber diameter distributions in the meltblown process result from complex interactions between capillary orifice configuration, viscoelastic polymer strands, and surrounding high-speed air stream. Even though the mechanism of meltblowing is extensively studied, a comprehensive understanding of the role of polymer melt rheology on fiber diameter, diameter distribution, process stability, and fiber breakage is still lacking. In this study, linear isotactic polypropylenes (PP) with a variety of melt flow rates (MFR) and narrow molecular weight distribution and PP Blend (PPB) were used to produce meltblown web in order to understand the role of polymer melt rheology on attenuation and instability development in meltblowing fiber formation and related to fiber diameter, diameter distributions and lower limit of fiber diameter at on-set failure points. The morphological characteristics of produced nonwoven samples have been determined by scanning electron microscope images and rheological characterization determined by capillary and parallel plate rheometer to find the melt viscosity (zero shear viscosity (\uD835\uDF020)) and melt elasticity which correlated here with the longest relaxation time (\uD835\uDF06).There are two critical questions in this study. The first is how polymer properties control fiber diameter and diameter distribution. The results have shown that an increase in viscosity and elasticity appears to make a statistically significant increase in median fiber diameters. Moreover, each polymer sample has different median fiber diameters at the same melt viscosity, although median fiber diameters are the same at the same melt elasticity for different PP resins. On the other hand, dispersity and skewness show the same trend. The dispersity and skewness decrease with increased melt elasticity, although melt elasticity has almost more effect on these parameters when polymer rheology is modified by molecular weight and temperature. In the following, PPB has been used to investigate the effect of melt rheology on fiber diameter and diameter distribution to modified melt rheology by changing the molecular weight distribution. The results have shown that an increase in melt elasticity for PPB makes a statistically significant increase in median fiber diameters. On the other hand, dispersity and skewness show the same trend. The dispersity and skewness decrease with the increase in melt elasticity. The results indicate that utilizing high molecular weight PP resin can stabilize the production of polymeric micro and nanofibers through the meltblown process.The second question of this study is how polymer properties influence melt strand instability and the onset of a process failure and achieving the smallest possible fiber diameter without defect formation. The following investigated melt strand stability and fiber breakage after die exit. The results have shown that the critical air drag force, which represents the melt strength of flow before fiber breakage, increases with the increase of melt viscosity and elasticity. There is a relationship between critical air drag force and polymer melt viscosity and elasticity when polymer rheology is modified by molecular weight and temperature, although the critical air drag force is almost the same at the same temperature and melt viscosity and it is not similar at the same temperature and melt elasticity which it can be related to the high molecular weight polymer resin used to make PPB. Then the results have shown that the critical draw ratio after die exit decreases with the increase of melt viscosity and melt elasticity. The critical draw ratio is not the same at the same melt viscosity and melts elasticity for different PP with different MFR when polymer rheology is modified by molecular weight and temperature. Also, the critical draw ratio after die exit is almost similar at the same temperature and melt viscosity, and it is not similar at the same temperature and melt elasticity when polymer rheology is modified by molecular weight distribution. Finally, the results show that the failure mechanism is almost similar for all polymer resins at different throughputs at critical points, and polymer melt rheology does not have too much effect on stress at the break and stability points.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798377684077Subjects--Topical Terms:

3698925
Skewness.
Index Terms--Genre/Form:

542853
Electronic books.

Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution.
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245 1 0 $a Effects of Polymer Rheology on Meltblowing Fiber Formation Process and Fiber Diameter Distribution.
264 0 $c 2023
300 $a 1 online resource (204 pages)
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338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-10, Section: B.
500 $a Advisor: Shim, Eunkyoung.
502 $a Thesis (Ph.D.)--North Carolina State University, 2023.
504 $a Includes bibliographical references
520 $a Meltblowing technology is one of the most economical ways to produce fine fiber webs. Properties and quality of web, fiber size, and fiber diameter distributions in the meltblown process result from complex interactions between capillary orifice configuration, viscoelastic polymer strands, and surrounding high-speed air stream. Even though the mechanism of meltblowing is extensively studied, a comprehensive understanding of the role of polymer melt rheology on fiber diameter, diameter distribution, process stability, and fiber breakage is still lacking. In this study, linear isotactic polypropylenes (PP) with a variety of melt flow rates (MFR) and narrow molecular weight distribution and PP Blend (PPB) were used to produce meltblown web in order to understand the role of polymer melt rheology on attenuation and instability development in meltblowing fiber formation and related to fiber diameter, diameter distributions and lower limit of fiber diameter at on-set failure points. The morphological characteristics of produced nonwoven samples have been determined by scanning electron microscope images and rheological characterization determined by capillary and parallel plate rheometer to find the melt viscosity (zero shear viscosity (\uD835\uDF020)) and melt elasticity which correlated here with the longest relaxation time (\uD835\uDF06).There are two critical questions in this study. The first is how polymer properties control fiber diameter and diameter distribution. The results have shown that an increase in viscosity and elasticity appears to make a statistically significant increase in median fiber diameters. Moreover, each polymer sample has different median fiber diameters at the same melt viscosity, although median fiber diameters are the same at the same melt elasticity for different PP resins. On the other hand, dispersity and skewness show the same trend. The dispersity and skewness decrease with increased melt elasticity, although melt elasticity has almost more effect on these parameters when polymer rheology is modified by molecular weight and temperature. In the following, PPB has been used to investigate the effect of melt rheology on fiber diameter and diameter distribution to modified melt rheology by changing the molecular weight distribution. The results have shown that an increase in melt elasticity for PPB makes a statistically significant increase in median fiber diameters. On the other hand, dispersity and skewness show the same trend. The dispersity and skewness decrease with the increase in melt elasticity. The results indicate that utilizing high molecular weight PP resin can stabilize the production of polymeric micro and nanofibers through the meltblown process.The second question of this study is how polymer properties influence melt strand instability and the onset of a process failure and achieving the smallest possible fiber diameter without defect formation. The following investigated melt strand stability and fiber breakage after die exit. The results have shown that the critical air drag force, which represents the melt strength of flow before fiber breakage, increases with the increase of melt viscosity and elasticity. There is a relationship between critical air drag force and polymer melt viscosity and elasticity when polymer rheology is modified by molecular weight and temperature, although the critical air drag force is almost the same at the same temperature and melt viscosity and it is not similar at the same temperature and melt elasticity which it can be related to the high molecular weight polymer resin used to make PPB. Then the results have shown that the critical draw ratio after die exit decreases with the increase of melt viscosity and melt elasticity. The critical draw ratio is not the same at the same melt viscosity and melts elasticity for different PP with different MFR when polymer rheology is modified by molecular weight and temperature. Also, the critical draw ratio after die exit is almost similar at the same temperature and melt viscosity, and it is not similar at the same temperature and melt elasticity when polymer rheology is modified by molecular weight distribution. Finally, the results show that the failure mechanism is almost similar for all polymer resins at different throughputs at critical points, and polymer melt rheology does not have too much effect on stress at the break and stability points.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Skewness. $3 3698925
650 4 $a Textile fibers. $3 659605
650 4 $a Membrane separation. $3 664305
650 4 $a Air flow. $3 914389
650 4 $a Viscosity. $3 1050706
650 4 $a Resins. $3 3682318
650 4 $a Rheology. $3 570780
650 4 $a Molecular weight. $3 3683783
650 4 $a Polymer melts. $3 3683586
650 4 $a Deformation. $2 lcstt $3 3267001
650 4 $a Geometry. $3 517251
650 4 $a Nonwoven fabrics. $3 659206
650 4 $a Mechanics. $3 525881
650 4 $a Physics. $3 516296
650 4 $a Textile research. $3 2153103
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0346
690 $a 0605
690 $a 0994
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a North Carolina State University. $3 1018772
773 0 $t Dissertations Abstracts International $g 84-10B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30364031 $z click for full text (PQDT)