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Innovative wet-spinning for manufacturing defect free PAN fibers: Electric current assisted process : 낮은 결점 PAN 섬유 제조를 위한 혁신 습식방사 공정: 전류인가 공정
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 유웅열 | - |
| dc.contributor.author | 양호성 | - |
| dc.date.accessioned | 2018-11-12T00:57:42Z | - |
| dc.date.available | 2018-11-12T00:57:42Z | - |
| dc.date.issued | 2018-08 | - |
| dc.identifier.other | 000000153105 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/143162 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2018. 8. 유웅열. | - |
| dc.description.abstract | Wet spinning is a conventional spinning process for making fibers. Wet-spun Poly-acrylonitrile (PAN) fibers have become more important since the discovery of PAN fibers in the 1960s that they can be transformed into carbon fibers through heat treatment. However, significant progress has not been made in wet spinning since the wet spun PAN fibers were commercialized in 1949. A new process parameter, such as the electric current, has not been introduced and its effect on the final properties of the PAN fiber has also not been investigated.
In this thesis, a new process, current-assisted wet-spinning, was developed, which is the first attempt in the world. The main idea of current-assisted wet-spinning was inspired by the electrospinning. In the electrospinning process, polymer solutions are continuously spun into nanometer-sized fibers without significant damage even at extremely high electric potential (tens of kV). Like electrospinning, the current-as-sisted process was carried out simply by applying electric potential to PAN solution in the existing wet-spinning process. Unlike electrospinning, the electric current in current-assisted wet-spinning process was several hundred microampere. The PAN fibers fabricated via the current-assisted wet-spinning process (EPANf) showed 20% higher mechanical properties than the PAN fiber fabricated via general wet-spinning process (GPANf). Various characterization methods were conducted for both samples to investigate the mechanism of improved mechanical properties in EPANf. It was revealed that the applied electric potential affected the coagulation environment in coagulation bath by forming ions in PAN solution, attracting more non-solvent (water). The more absorbed non-solvent in the PAN fibers (EPANf) minimized the enlargement of existing voids and nanocavitation during following drawing process, resulting in the enhanced mechanical properties of PAN fibers. Due to the simple set-up of current-assisted wet-spinning process, it is expected that the newly developed process can be applied to commercial wet-spinning process, offering new opportunities of innovating PAN fibers and their productions. | - |
| dc.description.tableofcontents | 1. Introduction 1
1.1. PAN fiber 1 1.2. PAN synthesis 2 1.3. Solution preparation 5 1.4. Wet-spinning process 6 1.5. Current-assisted wet-spinning 12 2. Current-assisted process: Electrospinning 14 2.1. Multi-layer coaxial electrospinning 14 2.1.1 Introduction 14 2.1.2 Experimental 16 2.1.3 Results and discussion 19 2.1.4 Summary 34 2.2. Multi-channel coaxial electrospinning 35 2.2.1 Introduction 35 2.2.2 Experimental 37 2.2.3 Results and discussion 40 2.2.4 Summary 55 3. Wet-spinning process: Basic setup 56 3.1. Wet-spinning for single filament 56 3.1.1 Experimental 56 3.1.2 Results and discussion 59 3.1.2.1 Solution parameters (concentration and flow rate) 59 3.2. Wet-spinning for multi filaments 64 3.2.1 Experimental 64 3.2.2 Results and discussion 66 3.2.2.1 Solution parameters (flow rate and solvation effect) 66 3.2.2.2 Jet stretch effect 71 3.2.2.3 Coagulation composition effect 76 3.2.2.4 Drawing ratio effect 80 3.3. Summary 84 4. Current-assisted wet-spinning: Basic setup 85 4.1. Current-assisted wet-spinning for single filament 85 4.1.1 Experimental (electric current introduction) 85 4.1.2 Results and discussion 87 4.2. Current-assisted wet-spinning for multi filaments 94 4.2.1 Experimental 94 4.2.2 Results and discussion 96 4.2.2.1 Solvent diffusion control by coagulation composition 96 4.3. Summary 104 5. Defect and mechanical properties of PAN filaments 105 5.1. The effect of coagulation composition 105 5.1.1 Experimental 105 5.1.2 Increased mechanical properties of single PAN filament 105 5.2. Analysis of multi PAN filaments 111 5.2.1 Experimental 111 5.2.2 Characterization 113 5.2.3 Results and discussion 113 5.2.3.1 Mechanical properties 113 5.2.3.2 Morphological observation 117 5.2.3.3 WAXD analysis 118 5.2.3.4 TGA, DSC, and DMA analysis 120 5.2.3.5 SAXS analysis 124 5.2.3.6 Chemical constituent analysis 128 5.3. Summary 134 6. Current-assisted wet-spinning mechanism 135 6.1. Experimental 135 6.2. Characterization 137 6.3. Results and discussion 138 6.3.1 PAN filaments with different methyl acrylate content 138 6.3.2 CNT-incorporated PAN filaments 152 6.4. Summary 157 7. Conclusion 158 References 160 Korean abstract 171 | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject.ddc | 620.1 | - |
| dc.title | Innovative wet-spinning for manufacturing defect free PAN fibers: Electric current assisted process | - |
| dc.title.alternative | 낮은 결점 PAN 섬유 제조를 위한 혁신 습식방사 공정: 전류인가 공정 | - |
| dc.type | Thesis | - |
| dc.contributor.AlternativeAuthor | Ho-Sung Yang | - |
| dc.description.degree | Doctor | - |
| dc.contributor.affiliation | 공과대학 재료공학부 | - |
| dc.date.awarded | 2018-08 | - |
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