INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Wei Huang,Huifang Wu,Xin Yan,Jiaxing Zhang,Zhaochi Feng,Miao Yang,Peng Tian,Xinwen Guo,Limin Ren
Nine-membered-ring (9-MR) STT zeolites hold immense potential in studying the impact of pore structure on catalytic performance. However, synthesizing pure-phase STT zeolites with tunable acid sites has been challenging. This study presents a rational approach for the rapid synthesis of STT zeolites from lamella Si-MWW zeolite via a chain rearrangement process, leveraging their structural similarities and the flexibility in manipulating MWW’s layer structure. Both zeolites share a common chain comprising ordered arrangements of 4-, 5-, and 6-membered rings, facilitating robust and rapid (10 h) STT growth, with a broad Si/Al ratio range. The resulting Al-STT zeolites exhibited an olefin product distinct from the 8-MR CHA and 10-MR MFI zeolites in the methanol-to-olefin reaction, underscoring the pivotal role of 9-MR pore structure. The findings not only advance the understanding of zeolite synthesis but also demonstrate the potential of tailoring pore structures to enhance the catalytic efficiency in industrially relevant processes.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
RSC Advances
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2022
·Vol. 12
·期 15
·9179-9185
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IF 4.036
Cai-Hong Liu,Hai-Tao Jiang,Chun-Hong Wang
Chitosan extracted from natural products has gained tremendous attention in the field of adsorption and separation due to its inherent biocompatibility and potential applications. In this research, we synthesized a new type of spherical chitosan adsorbent (SCA) by controlling the mass transfer rate of the entanglement of the polymer chains in the recombination process. This SCA is a highly crystalline polymer material with outstanding mechanical strength, high adsorption capacity, a porous surface and suitable particle size distribution. The value of the sphericity of attrition of this SCA was 89.8%, which is the same as that of the commercial macroporous resin with a polystyrene matrix. The X-ray diffraction (XRD) patterns and differential scanning calorimetry (DSC) curves showed a significant change from powder to spherical structure and confirmed that the SCA is highly ordered and crystalline. Optical microscopy (OM) and scanning electron microscopy (SEM) demonstrated that the SCA was composed of a tightly stacked fiber structure, indicating the homogeneity of the polymerization. The porous structure of the surface provided a channel for mass transfer, which was indicated by a test of the ion exchange capacity and the adsorption performance of the SCA with Cu(II) as the adsorbed subject. The adsorption capacity was higher than those of all reported non-composite chitosan materials. Therefore, we have successfully synthesized a completely green, nontoxic and environmentally friendly adsorbing resin equipped with excellent mechanical properties and adsorption capacity for future applications in many new fields.
研究领域:
材料科学
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环境科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER SCIENCE
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2022
·Vol. 60
·期 15
·2298-2308
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IF 3.046
Zhaolai Huang,Jiaqi Li,Mengxiao Zhang,Weilin Feng,Chuanjie Fang,Liping Zhu
Polymers of intrinsic microporosity (PIMs) are promising materials for membrane separation because their special rigid and contorted structures contribute to high permeability. However, their chain rearrangement to fill excessive free volume makes the permeability stability a tough challenge. In this work, we report on a new use of rutile nano-TiO 2 to mitigate the physical aging of PIM-1 (a typical PIM) nanofilms for stable permeability by mixing matrix. It was shown that the PIM-1 membrane incorporated with nano-TiO 2 displayed remarkably higher aging resistance with a lower swelling degree in long-term ethanol soaking, having more stable ethanol permeance with only a 5% decrease after 35 days, lower than 25% of the pure one. The mechanism of anti-aging was revealed by molecular simulation, thermal, tensile mechanical, and dynamic mechanical analysis. It was found that nano-TiO 2 had good compatibility with PIM-1 due to strong coordination interaction, making its uniform dispersion in polymer. Additional solvent permeation channels were also created to increase solvent permeance without compromising solute rejection. Due to the reliable interaction of nano-TiO 2 , which makes particles serve as physical crosslinking points, the movement of PIM-1 chains was limited partially to mitigate aging, enabling PIM-1-based membranes to have robust solvent permeation. Graphical
研究领域:
材料科学
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化学工程
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高分子科学
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DOI
高影响因子
MACROMOLECULES
·
2025
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IF 5.2
Ruirui Shi,Jinghao Hao,Han Liu,Yan Chen,Siliang Zhan,Haifeng Lu,Nijuan Sun,Hua Wang,Chuanjian Zhou
The stereochemistry of polymers governs their macroscopic mechanical and thermodynamic properties by regulating chain packing and crystallization behavior. Although the stereochemistry–structure–property relationship has been well-elucidated in symmetrically substituted polysiloxanes, it remains highly complex in asymmetrically substituted counterparts due to the propensity for siloxane backbone rearrangement. Taking asymmetrically substituted poly(methyl(3,3,3-trifluoropropyl)siloxane) (PMTFPS) as a model system, this study quantitatively characterizes its stereochemical configuration using 19F NMR spectroscopy and systematically elucidates the relationship between the feed ratio of cis-1,3,5-tris(3,3,3-trifluoropropyl)methylcyclotrisiloxane (cis-D3F) and the stereoregularity of PMTFPS. The results reveal that when the cis-D3F content exceeds 58%, the resulting PMTFPS exhibits typical features of isotactic polymers and displays semicrystalline behavior. With increasing isotacticity, the d-spacing of the crystalline phase gradually decreases, and the crystal morphology transitions from fibrous and lamellar structures to spherulitic domains under nonisothermal crystallization. Further mechanical testing demonstrates that silica-reinforced PMTFPS elastomers with high stereoregularity exhibit a pronounced self-reinforcement effect, attributed to enhanced strain-induced crystallization (SIC). This work not only uncovers the intrinsic correlations among stereochemical configuration, crystalline structure, crystallization kinetics, and macroscopic properties of PMTFPS but also offers valuable guidance for the stereochemical regulation and molecular design of high-performance asymmetrically substituted polysiloxanes.
研究领域:
高分子化学
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材料科学
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物理化学
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核磁共振波谱学
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结晶学
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机械工程
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产品关联
DOI
高影响因子
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