양이온성 셀룰로오스 나노섬유와 소수성 코팅제를 이용한 친환경 배리어 코팅 기술 개발 Development of Eco-friendly Barrier Coating Technology Using Cationic Cellulose Nanofiber and Hydrophobic Coating Agent원문보기
The cellulose nanofiber (CNF) is an eco-friendly functional polymer made from woody cellulose fiber. The CNFs have been estimated to be an effective barrier coating agent because of their excellent film formation, transparency and gas barrier properties by replacing synthetic polymers causing enviro...
The cellulose nanofiber (CNF) is an eco-friendly functional polymer made from woody cellulose fiber. The CNFs have been estimated to be an effective barrier coating agent because of their excellent film formation, transparency and gas barrier properties by replacing synthetic polymers causing environmental pollution. However, the CNF made from bleached kraft pulps has commonly negative charge and hydrophilic property due to the carboxylic acids and hydroxyl groups on cellulose molecules. The anionic nature of CNF weakens the electrostatic interaction between CNF and the anionic base paper, which makes it difficult to increase the coating weight. Moreover, the hydrophilic CNF cannot improve the water vapor transmission rate (WVTR) of the barrier-coated paper. Therefore, to expand the applications of barrier coating using CNFs, it is necessary to develop a technology capable of imparting hydrophobicity to barrier-coated paper while interacting with anionic base paper with CNF effectively. In this study, the multilayered barrier coating technology was developed using cationic and anionic CNFs, and a paraffin-free bio-wax to manufacture a barrier coated packaging paper. The anionic CNF was prepared by isolating hardwood bleached kraft pulp (Hw-BKP) using a microgrinder. Two types of cationic CNFs were prepared by the surface modification of Hw-BKP using polydiallyldimethyl- ammonium chloride (Poly-DADMAC) before microgrinding and by quaternization reaction of anionic CNF using GMA. The barrier coating of never-sized base paper was applied with a rod coater and the coating weight and air permeability of the barrier-coated paper were measured. Coverage by the CNFs was evaluated via scanning electron microscope images of the barrier-coated paper. To increase coat weight of barrier coated paper, the CNF consistency and rod number were controlled. Finally, water vapor transmission rate (WVTR) of barrier coated paper was measured after bio-wax coating. The coat weight, air permeability and coverage of the barrier-coated paper with cationic CNF made by surface modification and anionic CNF increased due to the electrostatic attraction between CNFs and base paper. Then the coat weight, air permeability and coverage of the barrier coated paper improved as CNF consistency and rod number increased. When the cationic CNF made by quaternization reaction was applied with anionic CNF, higher coat weight, air permeation resistance and coverage could be obtained at lower number of coating layers. To impart the hydrophobicity to barrier coated paper, the eco-friendly bio-wax was used to make the final barrier-coating layer. The bio-wax was effective to improve the water resistance and coverage of barrier coated paper. Finally, it was confirmed that CNFs were effective barrier coating agents and the cationic CNF increased the air permeability and coverage efficiently due to electrostatic interaction between cationic and anionic CNFs. In addition, the bio-wax improved air permeation resistance and hydrophobic property of barrier coated paper. Therefore, the multilayer barrier coating with cationic CNFs and bio-wax was effective for the manufacture of barrier coated packaging paper.
The cellulose nanofiber (CNF) is an eco-friendly functional polymer made from woody cellulose fiber. The CNFs have been estimated to be an effective barrier coating agent because of their excellent film formation, transparency and gas barrier properties by replacing synthetic polymers causing environmental pollution. However, the CNF made from bleached kraft pulps has commonly negative charge and hydrophilic property due to the carboxylic acids and hydroxyl groups on cellulose molecules. The anionic nature of CNF weakens the electrostatic interaction between CNF and the anionic base paper, which makes it difficult to increase the coating weight. Moreover, the hydrophilic CNF cannot improve the water vapor transmission rate (WVTR) of the barrier-coated paper. Therefore, to expand the applications of barrier coating using CNFs, it is necessary to develop a technology capable of imparting hydrophobicity to barrier-coated paper while interacting with anionic base paper with CNF effectively. In this study, the multilayered barrier coating technology was developed using cationic and anionic CNFs, and a paraffin-free bio-wax to manufacture a barrier coated packaging paper. The anionic CNF was prepared by isolating hardwood bleached kraft pulp (Hw-BKP) using a microgrinder. Two types of cationic CNFs were prepared by the surface modification of Hw-BKP using polydiallyldimethyl- ammonium chloride (Poly-DADMAC) before microgrinding and by quaternization reaction of anionic CNF using GMA. The barrier coating of never-sized base paper was applied with a rod coater and the coating weight and air permeability of the barrier-coated paper were measured. Coverage by the CNFs was evaluated via scanning electron microscope images of the barrier-coated paper. To increase coat weight of barrier coated paper, the CNF consistency and rod number were controlled. Finally, water vapor transmission rate (WVTR) of barrier coated paper was measured after bio-wax coating. The coat weight, air permeability and coverage of the barrier-coated paper with cationic CNF made by surface modification and anionic CNF increased due to the electrostatic attraction between CNFs and base paper. Then the coat weight, air permeability and coverage of the barrier coated paper improved as CNF consistency and rod number increased. When the cationic CNF made by quaternization reaction was applied with anionic CNF, higher coat weight, air permeation resistance and coverage could be obtained at lower number of coating layers. To impart the hydrophobicity to barrier coated paper, the eco-friendly bio-wax was used to make the final barrier-coating layer. The bio-wax was effective to improve the water resistance and coverage of barrier coated paper. Finally, it was confirmed that CNFs were effective barrier coating agents and the cationic CNF increased the air permeability and coverage efficiently due to electrostatic interaction between cationic and anionic CNFs. In addition, the bio-wax improved air permeation resistance and hydrophobic property of barrier coated paper. Therefore, the multilayer barrier coating with cationic CNFs and bio-wax was effective for the manufacture of barrier coated packaging paper.
주제어
#Barrier coating cationic CNF quaternization bio-wax gas barrier water vapor transmission rate electrostatic attraction
학위논문 정보
저자
이연희
학위수여기관
경상국립대학교 대학원
학위구분
국내석사
학과
임산공학과 목재화학및펄프·제지공학전공
지도교수
이지영
발행연도
2022
총페이지
vii, 65 p.
키워드
Barrier coating cationic CNF quaternization bio-wax gas barrier water vapor transmission rate electrostatic attraction
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