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Experimental and Theoretical Investigation of Jet Roping In Melt and Solution Blowing Set Up /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Experimental and Theoretical Investigation of Jet Roping In Melt and Solution Blowing Set Up // Vinod Kumar Balakrishnan.
Author:	Balakrishnan, Vinod Kumar,
Description:	1 electronic resource (366 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 86-04, Section: B.
Contained By:	Dissertations Abstracts International86-04B.
Subject:	Mechanical engineering. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31693710
ISBN:	9798384460602

Experimental and Theoretical Investigation of Jet Roping In Melt and Solution Blowing Set Up /
Balakrishnan, Vinod Kumar,

Experimental and Theoretical Investigation of Jet Roping In Melt and Solution Blowing Set Up /Vinod Kumar Balakrishnan. - 1 electronic resource (366 pages)

Source: Dissertations Abstracts International, Volume: 86-04, Section: B.

The main objective of this thesis is to investigate the probability of roping for smaller inter-needle distances during nonwoven formation processes. Nonwovens are materials comprised of fibers that are entangled physically and are bonded together mechanically, thermally or chemically. Nonwovens have become essential in our daily lives, in such applications as filtration media, life sciences, biomedical industry and its products (wipes, single-usage garb, etc.). In order to produce suitable polymer micro/nanofibers for various applications, several manufacturing techniques have been developed, including electrospinning, meltblowing, solution blowing, phase separation, self-assembly, and template synthesis. Specifically, solution blowing and meltblowing are widely used in industry not only because they are more cost-effective, but because they also possess high integrity of fabrication processes. Solution blowing process utilizes flow of a slowly moving polymer solution jet into a high-speed air co-flow. This process is used to form micro/nanofibers. In contrast to the other forms of fiber production, solution blowing can be easier applied to both petroleum-derived polymers and biopolymers (especially, bio-waste), thereby increasing the range of materials that can be utilized. Accordingly, multiple problems arise in relation to product innovation. Most-used fabrication technique in nonwoven manufacturing is meltblowing, which is employed in forming multiple products, including protective fabrics, filter media, wipes and medical gowns. In meltblowing, relatively slowly moving molten polymer jets are issued from a nosepiece into a high-speed co-flowing hot air stream. As a result, the polymer jets are stretched, bent and thus, additionally, stretched by the surrounding air stream. The thinning polymer jets are cooled, solidified and partially crystallized, as they are entrained by the surrounding gas further from the nosepiece. Eventually, the solidified polymer jets are deposited either on a moving belt or a stationary screen forming a nonwoven laydown. There are many potential defects which diminish the overall quality of meltblown products, like, in particular, die drool, flies, roping and shots. This thesis focusses on roping defect during non-woven production processes. How to quantify roping? What happens when multiple jets rope in flight? How much porosity of the laydown is affected by roping phenomenon? Also, how is the probability of roping affected by the processing parameters? In particular, figuring out inter-needle distances upto which probability of roping stays within statistically tolerable limit? Thus, the current study aims to establish novel theoretical, numerical, and experimental approaches, which are expected to elucidate the roping phenomenon in nonwoven formation processes. Such an insight would be helpful to foster improvements in the quality of nonwoven products and enhance throughput, particularly facilitating the use of nonwoven dies with reduced spacing between the needles.An insight into the effect of the operating parameters on the likelihood of roping in nonwovens can lead to an increased throughput and an optimization of such parameters. A progress in this direction facilitates opportunities for identifying the minimum inter-needle distance, at which nonwoven products reach a statistically tolerable level of roping. The industry utilizes high-density nosepieces for large-scale manufacturing and is interested in diminishing the inter-die distances as much as possible. The question is where the limit is, beyond which a severe roping could set in. An extremely 'dense'(large number of holes per inch) nosepieces potentially could result in a major drawback - the fiber-fiber roping. The optimization of die dimensions, the inter-die distances, facilitates an effective production of high-quality nonwovens.Polymer jets surrounded by a high-speed air flow experience aerodynamic forces causing bending instability. Bending instability induces whipping of polymer jets, hence, increasing the probability of a phenomenon called jet roping. Roping refers to the bundling or merging of two or more fibers, leading to the formation of exceptionally thick fibers (with diameters that are more than five-fold the average fiber diameter). Roping is scarcely explored in the literature and research which could shed additional light on this phenomenon is extremely important for applications. The primary cause for jet roping is the bending instability, which is equally characteristic of both solution blowing and meltblowing. Other characteristics, such as the solidification rate, and the corresponding structural differences in the resulting fibers, are secondary. Accordingly, the experimental investigation of roping in two and multi-fiber systems is evaluated in this thesis. Two and multi-fiber system was used to characterize end effect on probability of roping. The end effect stems from the fact that the high-speed airflow surrounding polymer jets results in the air-pressure gradient toward the polymer jets. This pressure gradient can cause significant roping of the outer polymer jets with their neighbors, whereas the inner jets are. (Abstract shortened by ProQuest).

English

ISBN: 9798384460602Subjects--Topical Terms:

649730
Mechanical engineering.
Subjects--Index Terms:

Fiber spinning

Experimental and Theoretical Investigation of Jet Roping In Melt and Solution Blowing Set Up /
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500 $a Source: Dissertations Abstracts International, Volume: 86-04, Section: B.
500 $a Advisors: Yarin, Alexander L. Committee members: Karpov, Eduard; Mirbod, Parisa; Ray, Suman Sinha; Komperda, Jonathan; Brown, Michael.
502 $b Ph.D. $c University of Illinois at Chicago $d 2024.
520 $a The main objective of this thesis is to investigate the probability of roping for smaller inter-needle distances during nonwoven formation processes. Nonwovens are materials comprised of fibers that are entangled physically and are bonded together mechanically, thermally or chemically. Nonwovens have become essential in our daily lives, in such applications as filtration media, life sciences, biomedical industry and its products (wipes, single-usage garb, etc.). In order to produce suitable polymer micro/nanofibers for various applications, several manufacturing techniques have been developed, including electrospinning, meltblowing, solution blowing, phase separation, self-assembly, and template synthesis. Specifically, solution blowing and meltblowing are widely used in industry not only because they are more cost-effective, but because they also possess high integrity of fabrication processes. Solution blowing process utilizes flow of a slowly moving polymer solution jet into a high-speed air co-flow. This process is used to form micro/nanofibers. In contrast to the other forms of fiber production, solution blowing can be easier applied to both petroleum-derived polymers and biopolymers (especially, bio-waste), thereby increasing the range of materials that can be utilized. Accordingly, multiple problems arise in relation to product innovation. Most-used fabrication technique in nonwoven manufacturing is meltblowing, which is employed in forming multiple products, including protective fabrics, filter media, wipes and medical gowns. In meltblowing, relatively slowly moving molten polymer jets are issued from a nosepiece into a high-speed co-flowing hot air stream. As a result, the polymer jets are stretched, bent and thus, additionally, stretched by the surrounding air stream. The thinning polymer jets are cooled, solidified and partially crystallized, as they are entrained by the surrounding gas further from the nosepiece. Eventually, the solidified polymer jets are deposited either on a moving belt or a stationary screen forming a nonwoven laydown. There are many potential defects which diminish the overall quality of meltblown products, like, in particular, die drool, flies, roping and shots. This thesis focusses on roping defect during non-woven production processes. How to quantify roping? What happens when multiple jets rope in flight? How much porosity of the laydown is affected by roping phenomenon? Also, how is the probability of roping affected by the processing parameters? In particular, figuring out inter-needle distances upto which probability of roping stays within statistically tolerable limit? Thus, the current study aims to establish novel theoretical, numerical, and experimental approaches, which are expected to elucidate the roping phenomenon in nonwoven formation processes. Such an insight would be helpful to foster improvements in the quality of nonwoven products and enhance throughput, particularly facilitating the use of nonwoven dies with reduced spacing between the needles.An insight into the effect of the operating parameters on the likelihood of roping in nonwovens can lead to an increased throughput and an optimization of such parameters. A progress in this direction facilitates opportunities for identifying the minimum inter-needle distance, at which nonwoven products reach a statistically tolerable level of roping. The industry utilizes high-density nosepieces for large-scale manufacturing and is interested in diminishing the inter-die distances as much as possible. The question is where the limit is, beyond which a severe roping could set in. An extremely 'dense'(large number of holes per inch) nosepieces potentially could result in a major drawback - the fiber-fiber roping. The optimization of die dimensions, the inter-die distances, facilitates an effective production of high-quality nonwovens.Polymer jets surrounded by a high-speed air flow experience aerodynamic forces causing bending instability. Bending instability induces whipping of polymer jets, hence, increasing the probability of a phenomenon called jet roping. Roping refers to the bundling or merging of two or more fibers, leading to the formation of exceptionally thick fibers (with diameters that are more than five-fold the average fiber diameter). Roping is scarcely explored in the literature and research which could shed additional light on this phenomenon is extremely important for applications. The primary cause for jet roping is the bending instability, which is equally characteristic of both solution blowing and meltblowing. Other characteristics, such as the solidification rate, and the corresponding structural differences in the resulting fibers, are secondary. Accordingly, the experimental investigation of roping in two and multi-fiber systems is evaluated in this thesis. Two and multi-fiber system was used to characterize end effect on probability of roping. The end effect stems from the fact that the high-speed airflow surrounding polymer jets results in the air-pressure gradient toward the polymer jets. This pressure gradient can cause significant roping of the outer polymer jets with their neighbors, whereas the inner jets are. (Abstract shortened by ProQuest).
546 $a English
590 $a School code: 0799
650 4 $a Mechanical engineering. $3 649730
650 4 $a Statistical physics. $3 536281
650 4 $a Applied physics. $3 3343996
650 4 $a Materials science. $3 543314
650 4 $a Aerospace engineering. $3 1002622
653 $a Fiber spinning
653 $a Non-woven processes
653 $a Entanglement
653 $a Roping
653 $a Optimization
653 $a Meltblowing
690 $a 0548
690 $a 0794
690 $a 0217
690 $a 0215
690 $a 0538
710 2 $a University of Illinois at Chicago. $b Mechanical and Industrial Engineering. $e degree granting institution. $3 3830120
720 1 $a Yarin, Alexander L. $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 86-04B.
790 $a 0799
791 $a Ph.D.
792 $a 2024
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31693710