재생섬유를 이용한 bio-degradable plastic 특성 및 응용

이진희,홍석준,박정윤,김형진 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

플라스틱은 합성 고분자로 연간 200만 톤 이상 소비되고 있으나 난분해성으로 인해 그 사용량을 줄이고자하는 움직임이 일고 있다. Cellulose acetate는 천연고분자로부터 화학적으로 유도된 물질이며 난분해성인 플라스틱의 대체물질임과 동시에 여러 가지 생분해성 플라스틱의 기초 원료로 이용된다. 이 물질은 치환된 수산기의 수에 따라 mono, di, tri-cellulose acetate로 구분되며 각각의 특성에 따라 안경태, membrane filter, 탁구공 등 여러 분야의 원료로 이용되고 있다. 본 연구에서는 반복 재생되어 그 형상이 조악한 재생섬유를 주원료로 하여 cellulose acetate의 합성을 유도하였으며 약품의 비율과 ash와 lignin 등 고지 중 포함된 cellulose외 물질이 아세틸화에 미치는 영향을 분석하였다. 또한 IR, NMR 등을 이용하여 제작된 cellulose acetate의 화학적 조성에 대해 분석하였고 TGA와 DSC를 이용하여 치환도가 반응물의 열적 특성에 미치는 영향을 분석하였으며, 추가적으로 제작된 recycled cellulose acetate와 PE(polyethylene)의 blending을 통해 그 보강 효과와 합성플라스틱의 대체 가능성에 대해 연구하였다.

적외선 분광법과 기계학습을 이용한 셀룰로오스 아세테이트의 치환도 예측 모델링

이용주,이지은,권재경,이태주,김형진 한국펄프·종이공학회 2023 펄프.종이기술 Vol.55 No.5

The objective of this study is to apply FTIR and machine learning models for the quantitative analysis of the degree of substitution of cellulose acetate. The models used for the degree of substitution analysis include PCA (principal component analysis), PLS-DA (partial least squares discriminant analysis), SVM (support vector machine), and KNN (k-nearest neighbor). The critical findings of this study indicated that it is possible to analyze the degree of substitution for cellulose acetate with a degree of substitution of 2.0 or less using IR spectrum data derived from acetylation, estimated through PCA. The decrease in explanatory power for degrees of substitution higher than 2.0 can be attributed to the chemical reaction rate. However, by applying SVM and utilizing the kernel trick to project the data into a high-dimensional feature space and perform non-linear classification, it was possible to create a degree of substitution discrimination model with excellent performance, regardless of the degree of substitution. As a result, the model for analyzing the degree of substitution of polymer monomers based on machine learning and IR spectrum data was proposed. It is believed that this model can efficiently replace existing analytical methods.

우수한 용융특성을 갖는 Cellulose acetate/Poly ethylene glycol조성물의 제조 및 특성 해석

이해성,이성준,정상원,김현철,김은주,고영준,이세근 한국안광학회 2012 한국안광학회지 Vol.17 No.1

목적: 본 연구는 cellulose acetate(CA)의 용융특성을 증가시키기 위해 polyethyleneglycol(PEG)를 도입함으로써 기존에 사용되는 환경유해성 가소제의 사용 없이 열가공성이 향상 된 CA/PEG 조성물을 제조하는데 목적이 있다. 방법: CA의 최적 가소화 조건을 확립하기 위해 PEG 분자량, 농도, 및 혼입온도를 제어하여 CA/PEG 조성물의 가소화 성능을 확인하였으며, CA와 PEG간의 혼화성을 확인하기 위해 제조된 조성물의 열분석 및 표면분석을 실시하였다. 또한 기존 상용 CA 레진과의 가소제 용출특성, 기계적 물성 및 광학적 특성들의 비교분석을 통해 가소제에의한 물성차이를 검토하였다. 결과: PEG의 도입을 통해 기존 상용 CA 레진과 유사한 가소화 성능을 확인하였으며, 최적의 가소화 조건은 PEG분자량 400, PEG 함량 30~40 phr, 가소화온도 175~180℃에서 우수한 용융특성을 나타냄을 확인 하였다. 또한 기존의 CA 안경테 소재와 비교 시 우수한 광택특성 및 안정성을 확인 하였으며, 동등수준 이상의 기계적 물성을 보임을 확인 하였다. 결론: CA/PEG 조성물은 환경 친화적 안경테 소재로써 기존 프탈레이트계가소제를 사용한 CA 안경테 소재를 대체할 수 있을 것으로 판단된다. Purpose: Cellulose acetate (CA) was blended with polyethyleneglycol (PEG) having different molecular weight at various mixing conditions to enhance melt-processibility of CA, which might prevent the harmful effect resulted from the introduction of phthalic plasticizer. Methods: To establish optimal plasticizing conditions, CA/PEG blends were examined under various plasticizing conditions: PEG concentration, molecular weight of PEG, and plasticzing temperature. Mechanical properties of the CA/PEG blends, as well as migration and exudation of the PEG, were performed in order to evaluate the efficiency of plasticization. Results: Compared to industrial CA resin plasticized by diethyl phthalate, CA/PEG blends exhibited similar thermal plasticization. It was established that the optimum condition was to blend 30~40 phr PEG with molecular weight 400 at 175~185℃. CA/PEG blend showed superior glassness, PEG stability, and mechanical properties. Conclusions: CA/PEG blends would be a eco-friendly glasses frame to substitute traditional CA glasses frame prepared phthalate plasticizers.

Antimicrobial activity of cellulose-based nanofibers with different Ag phases

Hyuk Jang, K.,Joon Yu, Y.,Ha Lee, Y.,Ok Kang, Y.,Ho Park, W. North-Holland 2014 Materials letters Vol.116 No.-

Cellulose acetate (CA) nanofibers containing Ag ions, CA (as-spun), were fabricated by electrospinning with 0.5 or 1wt% of silver nitrate (AgNO<SUB>3</SUB>). CA nanofibers containing Ag ions/nanoparticles (NPs), CA (UV), were prepared by UV irradiation of as-spun CA nanofibers. Also, cellulose nanofibers with Ag NPs, CA (UV+DA), were prepared by deacetylating the UV-irradiated CA nanofibers. The antimicrobial activities of Ag ions or NPs in nanofibrous matrices were examined against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. From conventional antimicrobial test for 18h, both Ag ions and Ag NPs in the CA or cellulose nanofibers exhibited strong antimicrobial activity against S. aureus. From kinetic antimicrobial test against E. coli for 30min, the CA (as-spun) showed faster bactericidal activity than the CA (UV) and CA (UV+DA) samples.

딥러닝을 기반으로 한 DC 마이크로그리드 상태추정

조윤호(Yoono Cho),김도윤(Doyun Kim),송화창(Hwachang Song) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10

최근 신재생 에너지원을 포함한 마이크로그리드가 점차 증가하고 있다. 이러한 상황에서 전력계통의 현 상태를 정확하게 파악하고 모니터링 및 제어하기 위하여 상태추정은 불가피하다. 에너지 관리 시스템(EMS, Energy Management System)의 프로세스에서 상태추정(Power System State Estimation) 위한 대표적인 방법은 가중최소자승법(WLS, Weighted Least Squares Solution)이다. 본 논문에서는 DC 마이크로그리드로 이루어진 6버스 시스템을 사용하여 기존 상태추정 방법인 가중 최소 자승법과 시계열 데이터에 효과적인 장 단기 인공신경망(LSTM, Long Short-Term Memory)을 이용해 상태추정을 수행하고 비교하여 보다 높은 성능을 보이는 상태추정기를 연구하였다.

Cellulose and its derivatives for application in 3D printing of pharmaceuticals

Giri Bhupendra Raj,Poudel Surendra,김동욱 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.1

Background Three-dimensional printing (3DP) has emerged as an advanced manufacturing technology capable of producing complex yet precise medicines intended for patient-centric drug therapy. However, printable materials currently available for 3DP are far too limited. Area covered The current article covers various cellulose-based polymers as well as their applications, especially in 3DP of oral solid dosage forms. The review focuses on their physicochemical properties, roles, and functions in conventional as well as 3DP dosage forms, and the characteristics of the obtained printed products are discussed. In addition, the challenges and considerations for processing cellulose-based feedstock materials are briefly presented. Expert opinion Cellulose and its derivatives are regarded as suitable polymers with a huge potential for applications in 3DP drug delivery systems. It is therefore essential to better understand cellulose-based printable polymers and their applications in 3DP.

Mechanical properties of cellulose acetate/hydroxyapatite nanoparticle composite fiber by electro-spinning process

이은주,곽대현,김득중 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.3

Synthetic biodegradable polymer matrix composites including bioactive ceramic phases are being increasingly considered for use as tissue engineering scaffolds due to their improved physical, biological and mechanical properties. Cellulose acetate composite fibers were prepared by electro-spinning of cellulose acetate doped with from 2.5 to 40 vol.% hydroxyapatite nano powder. The structure of the electro-spun web varied depending on the solvent types. The cross-linked morphology between fibers was obtained by the addition of benzyl alcohol. In this study, the effect of the spinning dope composition and the filler concentration on the morphology of electro spun cellulose acetate fibers was evaluated. The mechanical properties of the electro-spun single fiber were measured using a Thermo Mechanical Analyzer (TMA). The tensile strength of electro-spun fibers depended on the filler content.

Preparation of porous polymer membrane for application to cell separator

강상욱 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

The pores in cellulose acetate polymers for battery separators were generated by utilizing both hydrated metal salts such as Ni and water pressure. When cellulose acetate polymers complexed with hydrated metal salts were exposed to external water pressure, the continuous straight pores were generated in polymer. These results were attributable to that polymer chains became weakened by the plasticization effect by the hydrated regions in cellulose acetate. Furthermore, pore size could also be easily controlled by controlling the strength of external water pressure.

Electrospun polyvinylidene fluoride nanofibers with superhydrophilicity and improved biocompatibility

( Faheem Sheikh ),김헌 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

In this study, we had successfully prepared a colloidal solution consisting of polyvinylidene fluoride and cellulose acetate for obtaining nanofibers by electrospinning. The prepared nanofibers were characterized by SEM, FT-IR, TGA and XRD. These characterization techniques revealed that cellulose acetate can be easily introduced in polyvinylidene fluoride nanofibers using a colloidal solution, and this method favorably preserves the intact nature of cellulose acetate. The cell toxicity and cell attachment studies using NIH 3T3 fibroblasts indicated non-toxic behavior and good attachment of cells due to modification of cellulose acetate in polyvinylidene fluoride nanofibers.

Fabrication and Characterization of Array Tactile Actuator Based on Cellulose Acetate

Hyun-Chan Kim(김현찬),Sungryl Yun(윤성률),Hyun-U Ko(고현우),Jaehwan Kim(김재환) Korean Society for Precision Engineering 2015 한국정밀공학회지 Vol.32 No.8

This paper reports the enhanced fabrication and characterization of a 3 × 3 array tactile actuator composed of cellulose acetate. The array tactile actuator, with dimensions of 15 × 15 × 1 ㎣, consists of 9 pillar-supported cells made from a cellulose-acetate molding. The fabrication process and performance test along with the results for the suggested actuator are explained. To improve the cell-array fabrication, a laser cut was adopted after the molding process. The displacement of the unit cell increased the input voltage and frequency. Various top masses are added onto the actuator to mimic the touch force, and the acceleration of the actuator is measured under actuation. When 2 kV is applied to the actuator, the maximum acceleration is 0.64 g, which is above the vibrotactile threshold. The actuation mechanism is associated with the electrostatic force between the top and bottom electrodes.