• 펄프종이기술
• /
• 제47권6호
• /
• pp.22-40
• /
• 2015

Cellulose fibers is one of the most abundant in nature. It has many distinctive features: abundant in nature, biodegradable, non-toxic, eco-friendly, sustainable, easy to fabricate, hydrophilic, and cost-effective. Cellulose fibers, known as pulp, is produced from cellulose-containing materials by the pulping process. As the raw material, wood has been most commonly used while recycled pulp has been also used to some degree. Thus, pulp usually refers to wood pulp. Generally, the pulp and paper industry is regarded as the commodity market where the cost should be much more important than the quality. It also belongs to a mature market where the growth is slow, or even in decline. Accordingly, technological development has been rather stagnant for the industry. Recently, however, the pulp and paper industry has faced very serious challenges. First, due to digital technology, there has been a steady decline in the need for pulp and paper products. The digital industry has continuously replaced printed products such as books, newspapers, and magazines. Second, there has been a trend initiated by developed countries to limit the use of wood as the raw material for the sake of environmental protection. This forces the industry to find a more efficient use of wood pulp as well as finding alternative, non-wood sources. Third, as an individual becomes wealthier and more conscious of health-care, the quality of a product becomes more important than the cost. Thus, a paradigm shift is needed from the cost-conscientious to the quality conscientious. The objective of this article is to review the technologies aimed at engineering cellulose fibers for producing high-value added paper products.

• 한국식품과학회지
• /
• 제35권3호
• /
• pp.399-404
• /
• 2003

본 논문에서는 adipic acid(AA)와 1,4-butane diol(BD)을 반응 기질로 이용한 에스테르화 반응에 의하여 bis(4-hydroxy butyl) adipate(BHBA)를 생산하고자 하였으며, 이때 AA와 BD의 몰비율, 촉매(TBT)농도 및 반응온도 등이 에스테르화 반응에 미치는 영향을 검토함으로써 BHBA를 효율적으로 생산하기 위한 기초 최적화 조건을 제시하고자 하였다. AA와 BD 사이의 직접적 에스테르화 반응시 몰비율이 2.0 이상일 때, 반응속도를 살펴본 결과 몰비율([AA]/[BD])이 증가함에 따라 반응속도는 감소함을 확인하였으며, 촉매농도에 따른 반응속도를 살펴보았을 때 촉매농도가 증가할수록 반응속도상수가 증가함을 알 수 있었다. 또한, 반응온도가 증가함에 따라 반응속도상수는 무촉매와 촉매사용시 모두 증가하였으며, 무촉매 반응 및 촉매사용 반응시의 활성화에너지는 각각 198.5 kJ/mol 및 94.8 kJ/mol로서 TBT 촉매사용시 반응이 약 2배 정도 수월해짐을 알 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제34권1호
• /
• pp.49-58
• /
• 2008

Objective: The Purpose of the study was to investigate the bone morphogenic protein expression of rhBMP-2(recombinant human bone morphogenic protein-2) as singnaling molecule and ${\beta}-TCP$(Tricalcium phosphate) as a bone substitute and carrier medium of rhBMP-2. Materials and Methods: 16 rabbits divided into 2 group of each 8 rabbit. Two standardized bone defect, round bilateral defect was made in the cranium of the 8 rabbit of first group, and was grafted with $150{\sim}500{\mu}m$ diameter ${\beta}-TCP$ 0.25g in one side, which was soaked with rhBMP-2, and autogenous bone was grafted on another side as a positive control. Second group of 8 rabbit, only ${\beta}-TCP$ was grafted with same size and same manner. After 2, 4, 8, and 12 weeks, specimen was taken for microscopic immunohiostochemical and histomorphometric analysis. Result: Grafting ${\beta}-TCP$ with rhBMP show the early formation of the bone regenerative factor (BMP-4) and more quantity of new bone formation than only use of ${\beta}-TCP$ (8,12 week), even show less new bone formation than autogenous bone. Conclusion : The experimental study result that ${\beta}-TCP$ graft combination with rhBMP-2 as a delivery system is an effective with osteoinductive capacity and biodegradable properties, so that provide clinical availibility of composite use in reconstruction of bony defect.

• Journal of Periodontal and Implant Science
• /
• 제38권sup2호
• /
• pp.273-298
• /
• 2008

Purpose: The aim of this review is to introduce a novel bone-graft material for hard-tissue regeneration based on the calcium phosphate glass(CPG). Materials and Methods: CPG was synthesized by melting and subsequent quenching process in the system of CaO-$CaF_2-P_2O_5$-MgO-ZnO having a much lower Ca/P ratio than that of conventional calcium phosphates such as HA or TCP. The biodegradability and bioactivity were performed. Effects on the proliferation, calcification and mineralization of osteoblast-like cells were examined in vitro. Influence in new bone and cementum formations was investigated in vivo using calvarial defects of Sprague-Dawley rats as well as 1-wall intrabony defect of beagle dogs. The application to the tissue-engineered macroporous scaffold and in vitro and in vivo tests was explored. Results: The extent of dissolution decreased with increasing Ca/P ratio. Exposure to either simulated body fluid or fetal bovine serum caused precipitation on the surface. The calcification and mineralization of osteoblast-like cells were enhanced by CPG. CPG promoted new bone and cementum formation in the calvarial defect of Sprague-Dawley rats after 8 weeks. The macroporous scaffolds can be fabricated with $500{\sim}800{\mu}m$ of pore size and a three-dimensionally interconnected open pore system. The stem cells were seeded continuously proliferated in CPG scaffold. Extracellular matrix and the osteocalcin were observed at the $2^{nd}$ days and $4^{th}$ week. A significant difference in new bone and cementum formations was observed in vivo (p<0.05). Conclusion: The novel calcium phosphate glass may play an integral role as potential biomaterial for regeneration of new bone and cementum.

• 대한의용생체공학회:의공학회지
• /
• 제19권5호
• /
• pp.449-454
• /
• 1998

다공질 칼슘 인산계 세라믹스는 생체 친화성이 우수하여 경조직 대체재료로 사용되었을 때 새로운 인체 조직이나 실핏줄이 쉽게 성장해 들어가는 것으로 알려졌다. 본 연구에서는 여러 결정구조를 갖는 칼슘 메타인산염 중 화학적으로 가장 안정한 $\beta$형의 다공질 칼슘 메타인산염을 칼슘 인간염, Ca(H,PO,),를 열분해 시켜 제조하였다. 칼슘 인산염의 용융상태에서 냉각 중 생성되는 원통형 기공의 크기는 경조식 대체재료나 매트릭스로 사용되기 적절한 200$\mu$m로 만들기 위하여 응용온도에서 유지시간 또는 결정화 온도를 조절하였다. 본 실험에서 칼슘 인산염의 응용온도에서 유지시간을 길게 함에 따라 원통형 기공의 크기가 작아졌다.

• 한국건설순환자원학회논문집
• /
• 제8권2호
• /
• pp.204-211
• /
• 2020

PLA(Poly-Lactic Acid)섬유는 친환경소재이며 자연분해가 되므로 건설재료에 사용할 경우 내부 공극연결구조를 가진 다공성 재료의 제조가 가능하다. 본 연구에서는 국내에서 생산된 PLA 섬유(직경 0.5mm, 1.0mm, 길이 10mm)를 대상으로 강알칼리와 고온에서의 용해실험을 수행하였으며, 이를 이용하여 FA기반 지오폴리머에 활용하였다. 고온양생과 강알칼리 용액을 통하여 강도는 확보하였으나, 완전한 PLA 섬유의 용해을 확보하지 못하였다. 기존의 연구인 0.003mm의 직경에서는 완전히 용해하였으나 0.5mm는 약 42.5%, 1.0mm는 약 33.3%의 용해율을 가지고 있는 것으로 평가되었다. 또한 섬유의 체적이 커짐에 따라 양생시 부유하는 섬유가 발생하여 작업성과 용해에 부정적인 영향을 나타내었다. PLA 특성은 생산하는 원재료와 생산조건에 따라 달라질 수 있으나, 다공성 건설 자재로서 사용하기 위해서는 0.1mm 내외의 PLA 섬유의 사용이 바람직하다고 판단된다.

• 상하수도학회지
• /
• 제34권1호
• /
• pp.75-83
• /
• 2020

This study investigated the degradation characteristics and biodegradability of phenol, refractory organic matters, by injecting MgO and CaO-known to be catalyst materials for the ozonation process-into a Dielectric Barrier Discharge (DBD) plasma. MgO and CaO were injected at 0, 0.5, 1.0, and 2 g/L, and the pH was not adjusted separately to examine the optimal injection amounts of MgO and CaO. When MgO and CaO were injected, the phenol decomposition rate was increased, and the reaction time was found to decrease by 2.1 to 2.6 times. In addition, during CaO injection, intermediate products combined with Ca²⁺ to cause precipitation, which increased the COD (chemical oxygen demand) removal rate by approximately 2.4 times. The biodegradability of plasma treated water increased with increase in the phenol decomposition rate and increased as the amount of the generated intermediate products increased. The biodegradability was the highest in the plasma reaction with MgO injection as compared to when the DBD plasma pH was adjusted. Thus, it was found that a DBD plasma can degrade non-biodegradable phenols and increase biodegradability.

• Composites Research
• /
• 제31권6호
• /
• pp.371-378
• /
• 2018

본 연구에서는 폴리유산 나노복합재의 열탄성 거동을 예측하기 위해 분자동역학 전산모사를 수행하고 그 결과를 열탄성 미시역학 모델 예측해와 비교하였다. 폴리유산의 두 이성질체인 D유산(Poly D-lactide)와 L유산(Poly L-lactide)을 혼합한 스테레오 콤플렉스를 모델링하였고 이들을 기지로 사용한 탄소나노튜브 나노복합재를 구성하였다. 유산의 분해 유무에 따른 유리전이온도와 탄성계수 그리고 열팽창계수를 앙상블 전산모사를 통해 예측하였다. 미시역학 모델에서는 계면의 완전 결합을 가정한 이중입자 모델을 적용하여 탄성계수와 열팽창계수를 동일한 조성에서 예측하였다. 그 결과 열적 안정성에 있어 스테레오 콤플렉스에 탄소나노튜브가 첨가될 경우 유산의 뛰어난 계면 흡착과 이에 따른 열적 안정성 향상을 보였다. 순수한 유산과 나노복합재 모두 가수 분해에 따른 열적 특성 변화는 관찰되지 않았다. 또한, 스테레오 콤플렉스와 나노튜브 간 계면은 약한 불완전 결합상태 임을 알 수 있었다.

• 한국폐기물자원순환학회지
• /
• 제35권7호
• /
• pp.653-659
• /
• 2018

In the industrial wastewater that occupies a large proportion of river pollution, the wastewater generated in textile, leather, and plating industries is hardly decomposable. Though dyeing wastewater has generally been treated using chemical and biological methods, its characteristics cause treatment efficiencies such as chemical oxygen demand (COD) and suspended solids (SS) to be reduced only in the activated sludge method. Currently, advanced oxidation technology for the treatment of dyeing wastewater is being developed worldwide. Electro-coagulation is highly adapted to industrial wastewater treatment because it has a high removal efficiency and a short processing time regardless of the biodegradable nature of the contaminant. In this study, the effects of the current density and the electrolyte condition on the COD removal efficiency in dyeing wastewater treatment by using electro-coagulation were tested with an aluminum anode and a stainless steel cathode. The results are as follows: (1) When the current density was adjusted to $20A/m^2$, $40A/m^2$, and $60A/m^2$ under the condition without electrolyte, the COD removal efficiency at 60 min was 62.3%, 72.3%, and 81.0%, respectively. (2) The removal efficiency with NaCl addition was 7.9% higher on average than that with non-addition at all current densities. (3) The removal efficiency with $Na_2SO_4$ addition was 4.7% higher on average than that with non-addition at all current densities.

• 패션비즈니스
• /
• 제26권3호
• /
• pp.87-97
• /
• 2022

This study investigated the dyeability and color change of the natural dyes of SeaCell, a biodegradable functional fiber that is permanently added to cellulose fibers with natural additives extracted from seaweeds. The natural dyes used in the study are five dyes. Gardenia and turmeric, which are yellow-based natural dyes, Sappan wood and Lac, which are red-based natural dyes, and Indigo, a blue-based natural dye, were selected. The dyeability and color change according to the change of the mordant conditions and the number of times of dyeing were investigated. In addition, the dyeing properties and colors of cotton and silk fibers were compared under the same dyeing conditions as SeaCell. The study results are as follows. It was found that SeaCell had lower dyeing properties than silk, a protein fiber, in gardenia, sappan wood, and lac dyes, but had higher dyeing properties than cotton with the same cellulose component as SeaCell fibers. In the case of turmeric, it showed higher dyeing properties than cotton except for the no mordant condition. In the case of Indigo dye, SeaCell shows the best dyeability, indicating that it is a very suitable fiber for Indigo dyeing. As sustainable functional fibers are continuously developed in the future, natural dyes that are environmentally friendly and human-friendly are actively introduced and commercialized, and it is expected that they can be used as reference materials.