대나무섬유-열가소성 폴리우레탄 복합체의 특성 연구 = Characterization of bamboo fiber/Thermoplastic polyurethane composites

국문 초록 (Abstract)

고강도 및 물성을 요구하는 제품에서 기존의 합성섬유와 고분자 수지로 제조되는 고분자 복합재료는 폐기되었을 경우 분해되지 않아 환경오염을 초래하는 원인중 하나가 되어, 보강재로 쓰이는 섬유를 자연에서 풍부하게 얻을 수 있는 친환경섬유가 큰 관심을 받고 있다.
하지만 천연섬유와 고분자 수지간의 상용성 저하로 물성이 저하되며, 이를 개선하기 위해 알칼리처리, 전자빔, 등의 방법을 이용하여 섬유를 개질하지만, 이러한 방법은 습식 방법이거나 높은 공정 또는 장비비용이 동반되는 등 응용상의 어려움을 지니고 있어 공정이 단순하면서 복합재료의 물성을 향상시킬 수 있는 방법이 필요하다.
이에 따라 본 연구에서는 섬유의 개질 없이 매트릭스로 극성 고분자인 열가소성 폴리우레탄을 사용하여 상용성을 개선시킬 때 나타나는 물성효과를 확인하기 위해 실험을 진행하였다. 대나무섬유 함량을 5phr씩 증량시키며 실험을 진행하였고, 그 결과 섬유 함량이 증가할 때 인장강도는 감소하였지만, 100%,300% 모듈러스가 증가되는 경향을 나타냈다. 파괴신율은 다른 물성에 비해 상대적으로 많이 감소되지 않았으며, 인열강도는 15phr에서 최고점을 확인하였다. 수분 흡수율과 접촉각은 섬유 함량이 높아질수록 친수성기 증가로 인한 수분 친화성이 높아지는 것을 확인할 수 있었으며, 열 가속 노화 특성은 섬유 함량이 증가하였을 때 열에 의한 물성변화율이 개선되는 것으로 확인되었다.
이러한 연구 결과는 열가소성 폴리우레탄의 열 노화 특성을 개선시키거나, 향후 극성 고분자 섬유강화 복합재료 제조 연구 및 제조공정 단축으로 인한 제품의 단가 절감 연구에 이바지할 것으로 기대된다.

목차 (Table of Contents)

• 1. 서론 ···························································································································································· 1
• 2. 이론적 배경·············································································································································· 3
• 2.1 섬유강화복합재료(Fiber Reinforced Composite)·································································· 3
• 2.2 천연섬유(Natural Fiber)···················································································································· 6
• 2.3 천연섬유의 표면개질······················································································································ 12
• 2.4 폴리우레탄(Polyurethane)············································································································· 14
• 2.5 열가소성 탄성체(Thermoplastic elastomer)········································································· 15
• 2.6 섬유강화 복합재료의 성형··········································································································· 19
• 3. 실험···························································································································································· 24
• 3.1 실험재료················································································································································ 24
• 3.2 BF/TPU 복합체 시편 제조············································································································ 25
• 3.3 BF/TPU 복합체의 특성 분석········································································································ 26
• 4. 결과 및 고찰········································································································································· 30
• 4.1 대나무 섬유 함량에 따른 용융 흐름 지수 (Melt Flow Index)비교·························· 30
• 4.2 대나무섬유 함량에 따른 경도 특성 비교············································································· 32
• 4.3 대나무섬유 함량에 따른 인장강도 특성 비교···································································· 33
• 4.4 섬유 첨가에 따른 인열강도 특성 비교·················································································· 35
• 4.5 섬유 첨가에 따른 압축강도 특성 비교·················································································· 37
• 4.6 섬유 첨가에 따른 반발탄성 특성 비교·················································································· 39
• 4.7 섬유 첨가에 따른 열 노화 특성 비교···················································································· 40
• 4.8 섬유 첨가에 따른 수분흡수 특성 비교·················································································· 45
• 4.9 섬유 첨가에 따른 접촉각(Contact angle) 비교································································· 46
• 4.10 섬유 첨가에 따른 열 중량 특성 비교·················································································· 48
• 4.11 섬유 첨가에 따른 Morphology 비교···················································································· 50
• 5. 결론··························································································································································· 52
• 6. 참고문헌·················································································································································· 54