습식방사와 연신 공정이 Cellulose Nanofiber 필라멘트의 구조적 특성과 기계적 물성에 미치는 영향

다국어 초록 (Multilingual Abstract)

Abstract

In this study, the effects of spinneret diameter and TOCNF (TEMPO-oxidized Cellulose Nanofiber) content on the structural characteristics and mechanical properties of TOCNF filaments fabricated by wet spinning were investigated. In addition, a drawing process was applied to evaluate the enhancement of mechanical properties associated with structural changes before and after drawing. The diameter and tensile strength of the wet-spun TOCNF filaments were measured, while surface morphology was observed using scanning electron microscopy(SEM). The crystallinity index and orientation index of the filaments were analyzed using X-ray diffraction(XRD) and two-dimensional wide angle X-ray diffraction(2D‑WAXD). The results showed that, at a constant TOCNF content, decreasing the spinneret diameter led to a reduction in filament diameter and an increase in tensile strength, whereas the crystallinity index exhibited no significant change. This behavior is attributed to enhanced nanofibril orientation induced by increased shear conditions associated with smaller spinneret diameters. When the TOCNF content was varied under a constant spinneret diameter condition, the highest tensile strength was observed at lower TOCNF contents, while the crystallinity index remained within a similar range, indicating that differences in orientation efficiency played a dominant role in the mechanical performance. After applying the drawing process, both the crystallinity index and tensile strength increased for all TOCNF contents compared to the undrawn filaments. Notably, filaments with higher TOCNF contents exhibited more pronounced enhancement of crystal orientation along the fiber axis during drawing, which can be attributed to their higher maximum draw ratios. These findings indicate that the tensile strength improvement of TOCNF filaments arises from the synergistic increase in crystallinity and orientation induced by the drawing process. Through this study, it was confirmed that the enhancement of mechanical properties of TOCNF filaments is related to changes in structural characteristics resulting from wet spinning parameters and the drawing process.

목차 (Table of Contents)

• 1. 서론 1
• 2. 이론적 배경 5
• 2.1 CNF 5
• 2.2 TEMPO CNF 8
• 2.3 습식방사 9
• 2.4 연신 10
• 2.5 연구 목적 11
• 3. 실험 및 방법 12
• 3.1 실험 재료 12
• 3.2 시편 제조 14
• 3.2.1 TOCNF 함량별 제조 16
• 3.2.2 습식방사를 통한 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 제조 18
• 3.2.3 습식방사를 통한 TOCNF 함량별 필라멘트 제조 20
• 3.2.4 TOCNF 함량별 필라멘트 최대연신 22
• 3.3 측정 24
• 3.3.1 직경(Diameter) 분석 24
• 3.3.2 XRD(X-Ray Diffraction) 분석 25
• 3.2.3 2D-WAXD(Two-Dimensional Wide-Angle X-ray Diffraction) 분석 26
• 3.3.4 인장강도(Tensile strength) 분석 27
• 3.3.5 주사전자현미경(Scanning Electron Microscope, SEM) 분석 28
• 4. 결과 및 고찰 29
• 4.1 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 29
• 4.1.1 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 직경 29
• 4.1.2 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 XRD 31
• 4.1.3 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 인장강도 34
• 4.1.4 TOCNF 2.0wt% 구금 직경 크기별 필라멘트 SEM 36
• 4.2 TOCNF 함량별 필라멘트 38
• 4.2.1 TOCNF 함량별로 제조된 필라멘트 직경 38
• 4.2.2 TOCNF 함량별로 제조된 필라멘트 XRD 40
• 4.2.3 TOCNF 함량별로 제조된 필라멘트 인장강도 43
• 4.2.4 TOCNF 함량별로 제조된 필라멘트 SEM 45
• 4.3 TOCNF 함량별 최대연신 필라멘트 47
• 4.3.1 TOCNF 함량별로 제조된 필라멘트 최대연신율 47
• 4.3.2 TOCNF 함량별로 제조된 최대연신 필라멘트 직경 49
• 4.3.3 TOCNF 함량별로 제조된 최대연신 필라멘트 XRD 51
• 4.3.4 TOCNF 함량별 및 최대연신 필라멘트 2D-WAXD 54
• 4.3.5 TOCNF 함량별로 제조된 최대연신 필라멘트 인장강도 58
• 4.3.6 TOCNF 함량별로 제조된 최대연신 필라멘트 SEM 61
• 5. 결론 63
• 6. 참고문헌 65
• Abstract 73