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3D 인쇄용 필라멘트 제조 시 MFC 분산성이 필라멘트의 물리적, 열적 특성에 미치는 영향
류지애(Ji-Ae Ryu),최사랑(Sa-Rang Choi),안은별(Eun-Byeol Ahn),서은지(Eun-Ji Seo),박수정(Su-Jeong Park),엄태진(Tae-Jin Eom),이중명(Jung Myoung Lee) 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.1
In this study, thermal and physical properties of the 3D filaments fabricated with microfibrillated cellulose (MFC) reinforced polylactic acid (PLA) for fused deposition modeling (FDM) 3D printer were investigated. In order to produce a good dispersed filament of hydrophilic MFCs derived from lignin-less (F-MFC) and lignin-rich (R-MFC) fibers in a hydrophobic PLA matrix, two different dispersion methods were compared. The Type 1 method was powder-type MFCs and PLA fibers were simply mixed with inside an extruder and then MFC-reinforced filaments were produced at a given production condition. Another was the mixture of MFCs with a PLA solution dissolved in dichloromethane was dried into a complex form which was fed into the extruder to produce Type 2 filaments. It was confirmed through FE-SEM images that the hydrophilic MFC and hydrophobic PLA were uniformly distributed in the Type 2 filaments rather than Type 1 filaments. Also Type 2 filaments showed higher values in the tensile strength and elongation at break and a lower melting peak than those of Type 1 and neat PLA filaments. In addition, the filament derived from the lignin-less MFC (F-MFC) with the Type 2 method had the highest tensile strength and elongation at break and showed one melt peak between 50-250℃, suggesting a better dispersion of MFC in the hydrophobic matrix.
MFC-PCC Hybrid가 첨가된 수초지의 물성 평가
류지애(Ji-Ae Ryu),김강재(Kang-Jae Kim),나기백(Gi-Baek Nah),엄태진(Tae-Jin Eom) 한국펄프·종이공학회 2018 펄프.종이기술 Vol.50 No.3
The MFC-PCC hybrid was prepared by physical pre-treatment of MFC and PCC. physical pre-treatment refers to the state where MFC and PCC were homogenized. In this study, it was called MFC-PCC Hybrid. When the MFC-PCC hybrid was applied, not only the tensile strength and ash content of handsheets were high, but also the pore size decreased. Also, as the homogenization rate of MFC and PCC increased, tensile index and pore size of handsheets were decreased and then increased again. As a result of investigation the coagulation behavior of the MFC-PCC hybrid, the zeta potential decreased with increasing homogenization rate, and it was found that the MFC and PCC behaved in the order of coagulation-dispersion-coagulation. These results showed that electrostatic bonding between two factors was not always achieved through homogenization of MFC and PCC, and it was expected that the cohesion of several cases may affect the properties of handsheets. In this regard, future research will attempt to prepare the MFC-PCC hybrid by controlling the time.
Glycol Ether/NaOH 수용액에 의한 셀룰로오스계 시료의 용해
류지애(Ji-Ae Ryu),김강재(Kang-Jae Kim),안은별(Eun-Byeol Ahn),엄태진(Tae-Jin Eom) 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.1
The dissolution characteristics of glycol ether/NaOH solution were compared with NaOH/urea and PEG/NaOH solutions were reported. With decreasing of the particle size and concentration of the cellulosic micro-fines (CMFs), the dissolution ability of the CMFs was drastically increased in all solvents. Compared with the PEG/NaOH solution, the glycol ether/NaOH solution had been found to exhibit a similar or higher regenerated cellulose degree of polymerization as well as solubility. The FT-IR analysis also identified the differences between natural cellulose and regenerated cellulose. The shortening of particle length in the filter paper non-dissolved part was observed through optical microscopy, and for CMFs, swelling were observed in most particles. These results confirmed that the properties of raw materials particle size and degree of polymerization had a significant effect on dissolution and the glycol ether/NaOH solutions was a new solvent.