환원된 산화그래핀과 산화흑연의 오일 흡착특성에 관한 비교 연구

이시춘,Lee, Shichoon 한국섬유공학회 2014 한국섬유공학회지 Vol.51 No.6

Oil adsorption capacities of reduced graphene oxide (RGO) and graphite oxide (GO) were investigated and compared with commercial graphite products. Adsorption capacities were determined by measuring the adsorbed amounts using a tea bag containing the adsorbent materials. RGO and GO showed higher adsorption capacities than other graphite adsorbents. This is attributed to the increase in the interlayer spacing and consequent development of mesopore structures, resulting in a decrease in the bulk density and increase in adsorption. Expanded graphite (EG) prepared in the laboratory showed a worm-like structure and good adsorption; however, commercial milled EG showed low adsorption capacities because the pores were crushed.

SBS/SAN 블렌드계에서의 단축 압출 공정과 이축 압출 공정 비교

이시춘,김진국 국립경상대학교 공과대학 부설 첨단소재연구소 1993 尖端素材 Vol.3 No.-

The polymer blends have been attract attention with the development of the polymer industries. The investigation of the characteristics of SAN/SBS blends as a toughened polymer in this study. This study concentrated on the comparison of blending between by single screw extruder and by twin screw extruder. The results indicated that melt index, elongational property, impact strength increases with increasing butadiene content in SAN/SBS blends. However, hardness decreased with increasing butadiene content. The value of blends (30% of butadiene content) prepared by single screw extruder showed higher than by twin screw extruder in flow property. However, the hardness and the impact strength were not affected by extrusion method. In elongation, the single screw extruder had more advantage than twin screw extruder using high butadient content belends.

교합형 동방향 이축압출기의 스크류 조합에 대한 고찰

이시춘 ( Shichoon Lee ),김형수 ( Hyungsu Kim ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.3

교합형 동방향이축압출기는 고분자재료의 컴파운딩에 주로 사용되는 기계이다. 이축압출기는 가공하는 재료와 생산제품에 적합한 스크류 조합을 설계하여 품질과 생산성이 양호한 컴파운딩공정을 구축할 수 있다. 스크류조합을 구성하는 스크류와 니딩 엘리먼트의 종류, 형상 및 사양에 대하여 정리하였고, 각각의 엘리먼트가 조합될 때 고분자 수지의 가공성에 미치는 영향에 대하여 알아보았다. 범용수지의 대량생산에 보편적으로 적용되는 스크류 조합의 원리를 설명하였고, 피딩, 용융혼련 및 미터링영역에 적합한 스크류조합의 방향과 사례를 나열하였다. 액상첨가제나 무기필러의 사이드피딩, 반응압출, 탈기공정, 밝은 색상과 투명도가 요구되는 제품의 생산 및 겉보기비중이 낮은 재료의 가공 등 각각의 경우에 맞는 스크류조합의 방향과 원리를 제시하였다. An intermeshing corotating twin screw extruder is mainly used for compounding polymeric materials. Twin screw extruder can adopt modular-type screw configurations, which directly controls the quality and productivity of the products. The types, shapes, and specifications of the screw and kneading elements are summarized, and the effects of screw configuration on the processabiliy of the materials are discussed. The principles of screw configuration universally applied to mass production of general-purpose resins are explained, and the guidelines of screw combination according to the roles of feeding, melt mixing, and metering zones are listed. The strategies of screw combination suitable for various cases, such as side feeding of liquid additives or inorganic fillers, reactive extrusion, devolatilization process, production of products requiring bright color and transparency, and processing of materials with low apparent specific gravity, are presented.

Preparation of Non-flammable Wiper Paper by Simple H₃PO₃ Treatment

이홍찬,이시춘,Lee, Hong Chan,Lee, Shichoon Convergence Society for SMB 2020 융합정보논문지 Vol.10 No.6

매우 얇고 다공성 비인화성 와이퍼 용지를 아인산 수용액 처리에 의해 준비되었다. H₃PO₃ 처리는 와이퍼 용지의 난연성을 불연성 수준으로 개선시켰다. 열중량 분석 결과 700℃에서 잔량이 50%까지 증가했다. 이것은 본 실험과 같은 아인산 처리가 셀룰로오스 사슬의 탈수를 돕고, 연소중에 차르(char)와 유사한 구조의 형성을 촉진한다는 것을 의미한다. FT-IR과 X선 광전자 분광학에서는 H₃PO₃의 일부분은 셀룰로오스 사슬의 작용기와 반응하는 것으로 보였다. 반응한 아인산은 셀룰로오스의 체인의 탈수를 촉진하고, 차르와 같은 구조의 형성을 도와 와이퍼 용지의 난연성을 향상시킨다. A thin and porous non-flammable wiper was prepared by phosphorus acid solution treatment and subsequent oven annealing. The H₃PO₃ treatment improved flame retardancy of wiper paper to nonflammable level. Thermogravimetric analyses showed that residues increased to 50% at 700℃, which means this treatment helps dehydration of the cellulose chain and promotes the formation of char-like structures during the burning. FT-IR and X-ray photoelectron spectroscopy showed that some of the added H₃PO₃ could react with the functional groups of the cellulose chain. The reacted H₃PO₃ components promote dehydration of the cellulose components and the formation of a char-like structure and improve the flame retardancy of the wiper paper.

폴리아크릴산과 인산칼슘의 다층 레이어 형성을 통한 면 직물의 난연성 향상 기구의 연구

이홍찬,이시춘 한국섬유공학회 2022 한국섬유공학회지 Vol.59 No.6

Cotton fabrics with improved flame retardancy were manufactured by introducingcalcium phosphate groups into cotton fabrics using the LBL (Layer-by-layer deposition)method in which polyacrylic acid is used as one layer, and the flame retardant mechanismwas studied. As a result of scanning electron microscopy, the shape of the fabrics and cottonfiber not treated with LBL was destroyed, but the shape of the fabrics and the shape ofthe fibers were maintained in the LBL-treated cotton fabric. In the flame retardancy test ofthe LBL-treated fabrics, it was observed that numerous nanoparticles with a size of 40-60 nm were formed on the surface of the cotton fiber. In XPS (X-ray photoelectron spectroscopy)analysis, it can be confirmed that nanoparticles of calcium phosphate are generatedby the reaction between phosphoric acid and calcium. This result shows that flameretardancy was improved by a mechanism in which an incombustible calcium phosphatelayer is formed by a reaction between phosphoric acid and a calcium metal salt, as well asan increase in char formation of cellulose by phosphoric acid. XRD (X-ray diffraction analysis)confirmed that the nanoparticles produced were hydroxyapatite calcium phosphate. This result is significant in suggesting a new method for preparing hydroxyapatitenanoparticles by an environmentally friendly LBL method.

폴리아크릴산과 인산칼슘의 다층 레이어 형성을 통한 면직물의 난연성 향상

이홍찬,이시춘 한국섬유공학회 2020 한국섬유공학회지 Vol.57 No.5

This study was conducted to impart flame retardancy to cotton fabrics while maintaining their mechanical properties and appearance under environmentally friendly and room-temperature conditions. Anionic functional groups were prepared by adding polyacrylic acid to the cotton fabric. Calcium phosphate was grafted to polyacrylic acid by inducing a reaction between calcium ions and ammonium phosphate. In this layer-by-layer (LBL) deposition, 20 layers were formed. The results of a vertical flammability test revealed that the combustion of the multilayered fabrics was delayed and that the fabric structures were maintained, even after the combustion process. Thermogravimetric analysis showed that the residues of the multilayered cotton increased to 17% at temperatures above 500 °C. X-ray photoelectron spectroscopy confirmed the production of calcium phosphate. These results indicate that calcium ions reacted with and were grafted to the carboxyl groups of polyacrylic acid, and that the grafted calcium ions reacted with ammonium phosphate to generate calcium phosphate. These findings suggest that LBL deposition can be performed with calcium phosphate to produce cotton fabrics with improved flame retardancy in an environmentally friendly manner.

Polymorphs and morphological changes during dissolution in aging of CaCO3

이홍찬,이시춘 한국마린엔지니어링학회 2020 한국마린엔지니어링학회지 Vol.44 No.4

In this study, an experimental setup was designed to achieve accelerated aging of CaCO3 crystals in the laboratory to simulate the aging of calcite precipitates and biominerals caused by ocean acidification. CaCO3 was formed in the calcium aqueous solution through the inflow of CO2 from the atmosphere, and CaCO3 aging was conducted in the absence and presence of polyacrylic acid (PAA). When PAA increased, the maximum amount of deposited CaCO3 reduced, and the time to reach the maximum CaCO3 deposition was longer. However, there was a late onset of dissolution during aging. In the absence of PAA, typical rhombohedra eroded in the form of a plate or irregular sheet, but in the presence of PAA, some calcite nanofibers broke into nanoparticles. During aging, the calcite polymorph was not changed, but the relative intensity of the (104) plane to other peaks became weaker. This obser-vation implied that the crack in the calcite crystals propagated mainly in the (104) plane during aging. This experimental setup demonstrated that CaCO3 aging caused by ocean acidification can be simulated in the laboratory.

이온성 액체 첨가를 통한 폴리카보네이트의 난연성 향상 연구

이홍찬,이시춘,Lee, Hong Chan,Lee, Shichoon 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.6

Flame-retardant polycarbonates have been produced by addition of metal sulfonate compounds. However, the process is to be validated for thin-walled products. In this study, to improve flame retardancy of polycarbonate, an ionic liquid was additionally added. With a decrease in the second combustion time, a small quantity of the ionic liquid as less as 0.05 phr was enough to effectively meet the UL94 V0 protocol. Thermogravimetric experiments showed that the maximum weight loss rate increased with addition of the ionic liquid, indicating the sudden decomposition of polycarbonate. This sudden decomposition increased the rate of formation of char components during flaming, resulting in improvement of flame retardancy of polycarbonate.

Adhesion between partially miscible polymers

조길원,이시춘 한국고분자학회 1989 한국고분자학회 학술대회 연구논문 초록집 Vol.1989 No.10

압출공정법에 따른 고분자 물성의 변화

김진국,이시춘 한국고분자학회 1993 한국고분자학회 학술대회 연구논문 초록집 Vol.1993 No.4