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수중대향충돌 방식을 통한 TEMPO 처리 α-키틴(TOChNF)의 NaClO 농도에 따른 나노섬유화
서원정 ( Wonjeong Seo ),진정호 ( Jungho Jin ) 한국키틴키토산학회 2022 한국키틴키토산학회지 Vol.27 No.3
자연계에 풍부한 천연 고분자로써 생분해성, 향균성 및 우수한 기계적 특성 등의 장점에도 불구하고 섬유들 사이 수소결합에 의한 불용성으로 활용에 제한이 있었던 α-키틴의 나노섬유화를 진행하였다. TEMPO 매개 산화를 통한 화학적 전처리 후 수중대향충돌(ACC)이라는 하향식(top-down) 물리적 나노섬유화 과정을 통해 물리 화학적 나노섬유화 방법으로 균일한 크기의 키틴 나노섬유(ChNF)를 확보하였다. TEMPO 매개 산화 시 산화제로 사용된 NaClO의 농도를 조절하여 산화시켰을 때, 30 mmol NaClO 사용 후 ACC 처리하였을 때 가장 균일한 키틴 나노섬유(ChNF)가 관찰되었다. TOCNF는 나노섬유화 후에도 키틴 고유의 화학 및 결정구조를 유지하고 있음을 FT-IR 및 XRD분석을 통해 확인하였다. 또한 사용된 NaClO의 농도에 따른 분산안정성을 제타전위를 통해, 필름의 광학적 특성을 투과도 측정을 통해 그 값이 키틴 나노섬유화 정도에 따라 향상됨을 확인하였다. In this study, we reported on the nanofibrillation degree of TEMPO-oxidated α-chitin nanofibers (TOChNF) according to the oxidant NaClO concentration using aqueous counter collision (ACC) method as the means to implement the physical nanofibrillation of the TOChNF. We found that, for an equivalent ACC treatment level, the decrease of TOChNF diameter after TEMPO-mediated oxidation becomes more effective upon ACC treatment as the NaClO concentration is increased due to greater electrostatic repulsion between TOChNFs. Nevertheless, during the ACC treatment of the TOChNF, the original chemical and crystal structures were maintained. In addition, our Zeta potential analysis showed that the dispersion stability of TOChNF in aqueous suspension is improved as the NaClO concentration is increased. The solvent-casted film of the ACC-treated TOChNF also showed increased optical transmittance at higher NaClO concentration.
수중대향충돌 방식을 이용한 숙신산 무수물 개질 β-키틴 나노섬유의 제조
진정호,Lee Jongmin,Seo Wonjeong,Song Myeong-Oh,Oh Eunchan 한국키틴키토산학회 2022 한국키틴키토산학회지 Vol.27 No.2
In this study, we report on the production of succinylated β-chitin nanofibers (ChNF) via aqueous counter collision (ACC) method. Succinic anhydride (SA) mediated chemical modification is known as an effective nanofibrillation strategy for typical natural polysaccharides through the surface carboxylation, which has attracted attention due to its relatively mild characterisitics, such as non-toxicity. Using the combined physico-chemical treatment of SA and ACC, the succinylated β-chitin nanofiber (β-SChNF) was successfully prepared as a uniform hydrocolloidal suspension. The SEM and AFM analysis showed that the diameter of the SChNF ranged from 14 nm to 30 nm. The XRD and FT-IR analysis were used to confirm that the original crystal and chemical structure of chitin were maintained even after the physico-chemical nanofibrillation. We also fabricated a transparent film from the SChNF which showed a typical diameter-dependent optical transmittance; that is, the higher the number of ACC pass (i.e., smaller diameter of SChNF), the greater the optical transparency (80%). Our results show that SA chemical pre-treatment of β-chitin can boost successful nanofibrillation.