• Research Article

    Dynamic Causal Relationship between Imported Pulp and Wood Chip Prices

    수입 펄프 가격과 목재칩 가격 간의 동태적 인과관계 분석

    Eun-Su Han, Byung-Sam Yoon

    한은수, 윤병삼

    The purpose of this study is to investigate the dynamic causal relationship between imported pulp and imported wood chip prices. Results of … + READ MORE
    The purpose of this study is to investigate the dynamic causal relationship between imported pulp and imported wood chip prices. Results of the VAR model and the Granger causality test showed that the imported pulp price had a significant effect on the imported wood chip price, but the imported wood chip price did not affect the imported pulp price. This result implies that the imported pulp price leads the imported wood chip price. The impact response analysis revealed that the imported pulp price had a positive effect on the imported pulp and wood chip prices for up to 4 months, and the impact converges back to zero after 4 months. The impact of the price of imported wood chip had lasting effects on the price of imported wood chips for up to 4 months, then gradually decreased. According to the forecast error variance decomposition, the variation in the price of imported wood chip was mainly from shocks to the price of imported wood chip itself. The total variance of forecast error in imported pulp price decreased from 96.1% in 1 month to 63.7% in 12 months, and the price of imported wood chips increased from 3.9% in 1 month to 36.3% in 12 months. - COLLAPSE
    30 April 2024
  • Research Article

    Effect of Mechanical-Chemical Pretreatment at Room Temperature on Properties of Cellulose and Cellulose Solution

    상온에서의 기계적-화학적 전처리가 셀룰로오스 및 용액 특성에 미치는 영향

    Se-Young Oh, Feng Xu, Byoung-Uk Cho

    오세영, 서풍, 조병욱

    The high degree of polymerization (DP) of cellulose makes it difficult to dissolve the cellulose fibers and increases the viscosity of the … + READ MORE
    The high degree of polymerization (DP) of cellulose makes it difficult to dissolve the cellulose fibers and increases the viscosity of the dissolved cellulose solution, which limits the ability to produce small particles of beads by using small needles or nozzles by dropping or spraying methods. This study explores the development of a technology to control the DP of cellulose of a chemical pulp through a mechanochemical pretreatment at room temperature. The chemical pulp was pretreated by three methods (ethanol-hydrochloric acid pretreatment, ball milling pretreatment, or acid-ball milling pretreatment), and the effects on fiber and cellulose properties, cellulose solution properties, and bead size were explored. Our findings reveal that wet ball milling pretreatment with acid is more effective in reducing DP of cellulose than acid treatment or ball milling treatment alone. The DP of cellulose of chemical pulp was reduced from 1400 to 400 after 1 h of acid-ball milling treatment at room temperature. The reduction in the DP of cellulose decreased the viscosity and surface tension of the cellulose solution, which affected the size of cellulose beads. In addition, the acid-ball milling pretreatment resulted shortening of fiber length and external fibrillation, and did not affect the crystal structure of cellulose-I, unlike the ball milling treatment, which destroyed the fiber morphology and the cellulose crystal structure. - COLLAPSE
    30 April 2024
  • Research Article

    Preparation of Hydrophobic Cellulose Beads using Cellulose Dissolved in TEAH/Urea Solvent and AKD

    TEAH/요소 용제에 용해된 셀룰로오스와 AKD를 이용한 소수성 셀룰로오스 비즈 제조

    Minseok Jang, Byoung-Uk Cho

    장민석, 조병욱

    To expand the application of hydrophilic cellulose beads, we developed a technique to prepare hydrophobic cellulose beads with alkyl ketene dimer (AKD). … + READ MORE
    To expand the application of hydrophilic cellulose beads, we developed a technique to prepare hydrophobic cellulose beads with alkyl ketene dimer (AKD). The cellulose solution was prepared by dissolving chemical pulp in tetraethylammonium hydroxide (TEAH)/urea solvent, followed by the addition of AKD to disperse it at room temperature. Cellulose beads were prepared by dropwise addition of the cellulose-AKD suspension into acetic acid solution, followed by washing and drying. The effects of AKD addition on the cellulose-AKD suspension and the properties of the AKD-modified cellulose beads were investigated. It was confirmed that the cellulose beads were chemically modified by AKD, resulting in enhanced hydrophobicity. The addition of AKD to the TEAH/urea/cellulose solution led to a reduction in viscosity and surface tension. Compared to unmodified cellulose beads, AKD-modified cellulose beads exhibited lower water retention value (WRV) and water absorption capacity, as well as increased oil absorption. They also exhibited relatively higher strength (lower deformation) when swollen in water. - COLLAPSE
    30 April 2024
  • Research Article

    The Characteristics of Wet-laid Nonwoven Sheet Using Lyocell/Wood Pulp Fibers

    Lyocell/Wood pulp 섬유를 활용한 Wet-laid Nonwoven 시트의 특성

    Soon Wan Kweon, Yong Ju Lee, Do Young Lee, Jeong Rak Choi, Hyoung Jin Kim

    권순완, 이용주, 이도영, 최정락, 김형진

    Nonwoven fabrics are widely utilized in various industries due to their excellent bulk characteristics, productivity, and flexibility. With increasing global interests in … + READ MORE
    Nonwoven fabrics are widely utilized in various industries due to their excellent bulk characteristics, productivity, and flexibility. With increasing global interests in environmental sustainability, there is a growing trend towards utilizing biodegradable and renewable raw materials in nonwoven production. In this study, we employed papermaking technology to fabricate wet-laid nonwoven fabric using Lyocell, a natural regenerated cellulose fiber, and wood fiber. We aimed to investigate the influence of fiber selection and mixing ratio on mechanical and surface properties. Mechanical property analysis revealed that the inclusion of wood fiber led to improve strength while reducing bulk due to the low density and smooth surface structure of Lyocell. To analyze surface characteristics, surface roughness and surface friction were analyzed, and as a result of analyzing each parameter, the coefficient of determination (R2) of the two parameters was 0.02, which was analyzed as an independent variable. Therefore, it was judged that a complementary approach considering both variables was necessary. As a result of surface roughness analysis, it was difficult to identify significant differences due to increasing the ratio of lyocell to wood fiber. However, as a result of the surface friction analysis, the F-MAD of the wet nonwoven fabric made only with Lyocell fiber showed a value of 0.043, and the value decreased when 50% wood fiber was mixed, confirming the possibility of improving softness. Furthermore, the analysis highlighted the influence of fiber length and width on softness, suggesting the importance of fiber characteristics in nonwoven fabrication. Overall, our findings suggest that incorporating wood fibers in wet-laid nonwoven manufacturing can enhance both strength and softness. These results provide insights for future nonwoven manufacturing technologies and quality control strategies. - COLLAPSE
    30 April 2024
  • Research Article

    A Study on the Post-treatments of Citrus Pomace-based Soil Covering Materials for Improving Functional Properties

    감귤박 기반 토양피복재의 기능성 강화 후처리 연구

    Yu-jin Lee, So-hyun Kim, Myung Suk Shin, Joung Eun Kim, Yong Joo Sung

    이유진, 김소현, 신명석, 김정은, 성용주

    This study investigated the application effects of biodegradable coatings and surface heat treatment to improve the properties of citrus peel soil covering … + READ MORE
    This study investigated the application effects of biodegradable coatings and surface heat treatment to improve the properties of citrus peel soil covering materials used in landscaping and horticulture, aiming to enhance the utilization of citrus by-products. Various coating methods including soaking, roll-coating, and spray coating were applied to address the uneven surface structure of citrus peel soil covering materials. The spray coating method showed the relatively uniform coating results and provided the accurate control of coating amount adjustment. The effects of biodegradable coatings such as starch, acrylic-based coatings, and rosin emulsions were compared and evaluated, revealing that the starch coating exhibited the highest increase in strength while the acrylic-based coating was most effective in enhancing water resistance. It was observed that increasing the number of spray coating times could increase the strength and the resistance to water disintegration. It was possible to increase the coating amount depending on the number of spray coating times, leading to improvements in strength and he resistance to water disintegration. Surface heat treatment using direct flame was conducted, resulting in increased the resistance to water disintegration through surface carbonization. Through these surface coating and treatment methods, this study confirmed the potential for improving the quality and functionality of citrus peel soil covering materials, providing foundational data for the production of functional citrus peel soil covering materials. - COLLAPSE
    30 April 2024