CELLULOSE
·
2025
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IF 4.8
Gunawan Ivana,Zhang Yue,Wang Huijie,Kou Mengtian,Wang Chao,Zhang Yumei
Pulp pre-treatment acts as a preliminary treatment in the lyocell process, allowing aqueous NMMO solvent molecules to penetrate the wood fiber structure. The present paper first determines cellulose’s pre-swelling, swelling, and dissolution phenomena in NMMO aqueous solutions of different concentrations and temperatures. It was found that instead of “ pre-swelling ” and “ dissolution ”, the “ swelling ” action during pre-treatment develops the most suitable interaction between wood pulp fiber and solvent. Higher concentrations of NMMO aqueous solutions (70–80%) do not contain enough water and that limits the uniform wetting of the pulp, while a lower NMMO concentration (50%) is not able to fully establish the hydrogen bonding interaction between cellulose and NMMO. The pre-treatment of cellulose pulp using 60% NMMO aqueous solution at 65 °C can ensure that NMMO itself does not degrade and provides sufficient solvent diffusivity for pulp based on the swelling effect. This significantly reduces heterogeneous microstructure aggregation and effectively promotes subsequent dissolution processes. The dissolved cellulose has more uniformity at the molecular level, showing lower dope relaxation time and gel temperature, which offers better alternatives for stable, high-viscosity lyocell spinning, and constructs stronger fiber compared to that of un-treated pulp.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2022
·Vol. 29
·期 2
·751-762
·
IF 6.123
Cui Shiqiang,Zhang Yang,Liu Changjun,Lou Shanhao,Zhang Yue,Zhang Yumei,Wang Huaping
In order to research the multi-level structure of Lyocell fiber at different draw ratios and to reveal the limiting factors for preparing the high strength Lyocell fiber, the paper reports on the effect of draw ratio including low drawing (1–5), high drawing (6–11) and excessive drawing (12–20) on the multi-level structure and the mechanical properties of Lyocell fiber. The structure was determined by wide-angle X-ray diffraction, small-angle X-ray scattering and fibrillation test, and the result showed that, at low draw ratio stage, the breaking strength, yield strength and modulus of the fiber increased with the draw ratio owing to crystallinity as well as orientation increased while the micropore decreased, and there were almost no microfibrils on the fiber surface. At high draw ratio stage, the orientation of amorphous region increasing was the principal reason for the increase of fiber mechanical properties, and the micropores continued to decrease and a few short and thick microfibril was formed. At excessive draw ratio stage, the breaking strength remained constant mainly due to the basically unchanged crystallinity and orientation of the fibers, the yield strength and modulus decreased due to the slip of the highly crystallized and oriented elementary fibril. Meanwhile, the micropores still decreased and became more slender, the number of microfibrils increased and the microfibrils showed tenuous structure. It can be summarized that Lyocell fiber has the characteristics of multi-level structure, and the fundamental reason limiting the improvement of mechanical properties with draw ratio increasing is the slip of elementary fibril.
研究领域:
材料科学
·
纤维化学
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2024
·
IF 4.9
Zhao Zhaojun,Yang Zhuo,Zhang Xingmin,Sun Yaqian,Wang Qingmiao,Zhou Hang,Min Jie
Lyocell fibers are currently claimed as green fibers with good application prospects, but the major problem of fibrillation restricts further promotion and application. In this study, based on the theory of hydration lubrication at the solid/liquid interface, hexamethylene-diisocyanate trimer (HDIt), polyethylene glycol (PEG), and butanone oxime (MEKO) were used to synthesize a reactive hydrophilic triblock polyurethane (RHT-PU). RHT-PU could construct a water lubrication layer on the lyocell fiber surface via H-bonding between polyoxyethylene ether and water molecules, reducing the coefficient of friction (CoF) of the fiber interface in the water. It was found that PEG molecular weight and grafting density had significant effects on the CoF of modified fabrics, with CoFs decreased with increased PEG molecular weight and grafting density. In water, the CoFs of fabrics modified by RHT-PU were reduced from 0.45 to 0.32 and maintained lower CoFs at higher temperature and higher normal loads. After mechanical friction and household washing tests, the surface abrasion of modified fabrics were significantly improved and color fading grade of fabrics raised from 3 grade to 4–5 grade. Construction of water-lubricated interfaces effectively reduced fibrillation.
研究领域:
材料科学
·
纺织工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jialin Li,Yu Wang,Ye Zhang,Wei Zhao,Wenzhe Bao,Yufeifan Duan,Junwei Yu,Bo Zhu,Kun Qiao
Currently, the hydrogen storage application of carbon-based adsorbent materials is mostly implemented under the pressure conditions of 30–300 bar, while there is few targeted studies conducted on the unsaturated adsorption under ambient pressure conditions. Therefore, based on industrialized Lyocell biopolymer fiber precursors and the enhancement effects of dipole-induced hydrogen bonds (DIHB), this work presents a facile construction strategy for P/O co-doped Lyocell-based porous carbon fiber cloth (Ly-ACF-F40). By the technical route of thermal stabilization---sonication assisted phosphoric acid activation---hydrogen bonds introduced by interfacial fluorination, the constructed Ly-ACF-F40 acquires a high specific surface area (1870 m 2 /g) and total pore volume (1.277 cm 3 /g), and an excellent hydrogen storage capacity of 3.22 wt% under ambient pressure conditions (77 K, 1 bar). The study directly demonstrated in the experiment that dipole induced hydrogen bonding H(I)-H(II)···F can effectively enhance the atmospheric hydrogen storage density on the basis of other eliminating influencing factors of specific surface area. The simple construction strategy of porous carbon-based materials can provide reference for the research of unsaturated adsorption hydrogen storage materials under ambient pressure conditions, also assist in the application and promotion of low-cost solid hydrogen storage materials.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chunlong Zuo,Yongli Zhang,Wei Tan,Jieyun Zhao,Lina Jiang,Yuanlin Ren,Xiaohui Liu
Traditional epoxy resins are manufactured from non-renewable fossil resources and suffer from several drawbacks, including poor flame retardancy, non-reprocessability and recycling difficulties, greatly affecting their wider applications. To address these issues, an inherent flame-retardant epoxy resin (L-Trp@PA/TPEP) was synthesized from biomass tea polyphenols, L-tryptophan, phytic acid and epichlorohydrin. L-Trp@PA/TPEP achieved a limiting oxygen index (LOI) value of 36.4%, with excellent anti-dripping, self-healing and reprocessability. Additionally, due to the limited number of reprocessable cycles, a versatile durable Lyocell fabric (L-Trp@PA/TPEP/Lyocell) was fabricated by finishing with the recycling of non-reprocessable L-Trp@PA/TPEP. L-Trp@PA/TPEP/Lyocell showed an LOI value of 34.5% and ultraviolet protection factor of 137.29. The elongation at break and tensile strength of modified Lyocell fabric increased by 19.2% and 33.6%. In addition, the modified fabric had favorable chemical resistance without mechanical deterioration within the pH range of 1 to 13. Besides, L-Trp@PA/TPEP/Lyocell displayed remarkable anti-fouling and self-cleaning capabilities. This work proposed a comprehensive and eco-friendly approach in terms of raw materials, application and recycling, which was significant for the development of sustainable novel materials and multifunctional textiles.
研究领域:
材料科学
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可持续发展
·
纺织工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）