Journal of the Taiwan Institute of Chemical Engineers
·
2022
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IF 5.477
Bingying Gao,Chao Yao,Linqiang Mao
Background Advanced aerogels with lightweight, flame retardant and rapid cooling properties are urgently needed as thermal insulators in harsh environments. Method The Cr 2 O 3 −Al 2 O 3 aerogels were fabricated by simple method and freeze-dried process. A large number of pores were produced in the microstructure of samples by carbonization of soluble starch during calcination. Findings The porous structure makes the density of prepared Cr 2 O 3 −Al 2 O 3 aerogel as low as 0.0060 g·cm −3 and the thermal conductivity as high as 0.30 W m −1 ·K −1 , which indicates that the sample has good thermal dissipation and rapid cooling performance. The effect of calcination temperature on cooling rate was studied. The results show that material cooling can be divided into two stages, the second stage is the speed control step. With the increase of the calcination temperature, the cooling rate of sample improves and the cooling time decreases. The prepared Cr 2 O 3 −Al 2 O 3 aerogels have good flame retardancy and cannot ignite upon exposure to the burner for 2 min. The flame retardancy and rapid cooling mechanism of the sample was also studied. The Cr 2 O 3 −Al 2 O 3 aerogels have the advantages of lightweight, flame retardancy and rapid cooling, which has potential application prospects in the field of flame retardant cooling coatings.
研究领域:
材料科学
·
热能工程
✓ 已验证
DOI
高影响因子
Small Methods
·
2021
·Vol. 6
·期 1
·2101156
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IF 14.188
Tongtong Liu,Shaoxuan Yang,Jingyu Guan,Jin Niu,Zhengping Zhang,Feng Wang
Defects have a significant impact on the electrocatalysts performance. Introducing defect structures in metal oxides such as pyrochlores and perovskites has proved to be an effective strategy to enhance electrocatalytic activity. However, it is hard to build numerous defect sites in such high-temperature oxides due to the strong metal–oxygen bonds and the so-called self-purification effect, which becomes increasingly important as the particle size reduced to the nanoscale. Here, a facile strategy is demonstrated to fabricate defect-rich yttrium ruthenate oxides Y 2 Ru 2 O 7− δ with the pyrochlore structure (denoted D rich -YRO) by the liquid nitrogen (<−196 °C) quenching. Owing to the almost instantaneous cooling in oxygen-deficient condition, a large number of defects—including oxygen vacancies, grain boundaries, pores and surficial disorder—are preserved in the room temperature material and act as electrocatalytic active sites for oxygen evolution. As a result, D rich -YRO shows excellent catalytic activity and high electrochemical stability, along with a high performance in the operation of proton exchange membrane electrolyzer. The quenching strategy employed in this work provides a facile approach for constructing defect-rich structures in high-temperature oxides and should lead to new applications in energy conversion and storage devices for such materials.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Zhiyuan Yu,Tianyi Huang,Shafqat Ullah,Yujun Wang,Guangsheng Luo
1T-phase MoS2, a versatile two-dimensional transition-metal dichalcogenide, is typically synthesized using a one-pot hydrothermal method. However, inadequate control of the sulfurization, reduction, and crystallization processes in the autoclave leads to multilayer 1T-MoS2 with high crystallinity, a small surface area, and few defects. Considering the aforementioned issues, a two-stage microreactor continuous hydrothermal flow synthesis (CHFS) system coupled with accurate control and rapid processing is used to prepare 1T-MoS2 with abundant voids and a large surface area under 250 °C and 4.0–4.5 MPa. And density functional theory calculations reveal that nitrogenous species, acting as reductants and electron donors, lower the energy of 1T-MoS2 by intercalation and surface adsorption, facilitating its swift synthesis within the presulfurization stage for 10 min and reduction stage for 24 min. The precisely controlled synthesis of porous 1T-MoS2, originating from prenucleation clusters, results in a large surface area of 201.5 m2/g, concentrated mesopores of 2–5 nm, and a pore volume of 0.58 cm3/g. Moreover, a significant transformation from the 1T to the 2H phase is prevented by rapid cooling downstream of the CHFS system.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Feifei Yan,Hanchuan Li,Shanlin Cui,Jiahui Sun,Qiuyang Ye,Yanping Liu,Chuntai Liu,Zhen Wang
In many industrial processes, polymer melt undergoes complex flow-cooling environments before being solidified into the final products. Investigating polymer crystallization under processing conditions is a necessary step to predict and customize the structures and properties of semicrystalline polymers. Herein, the crystallization behavior of high-density polyethylene (HDPE) under combined melt stretching and fast cooling fields was studied through a homemade extensional rheometer. A series of HDPE samples were prepared by cooling the stretched melt at different cooling rates (0.02–220 ° C/s) immediately after flow, or after waiting for different times of isothermal crystallization at 128 °C. Microstructural characterizations confirm four different structural states related to the evolution of shish-kebabs after melt stretching, namely generation of shish precursors, shish crystal growth, kebab lamellar growth, and perfection of shish-kebabs, which diversify greatly the structures and morphologies of the final solidified samples. By prolonging the isothermal crystallization time at high temperature, the fast cooling-induced lamellae keep decreasing in thickness. This supports the occurrence of molecular segregation caused by shish-kebabs growth at high temperature, which reduces the molecular weight of the remaining un-crystallized melt. In addition, quantitative analysis of crystalline orientation manifests that the lamellar growth during isothermal process takes strictly the shish as a template and adopts a high orientation, while the fast cooling-induced lamellae are only related to the chains conformation of un-crystallized melt prior to cooling. This work would be essential to advance the in-depth understanding on the actual industrial processing of semicrystalline polymeric materials.
研究领域:
材料科学
·
聚合物物理
✓ 已验证
产品关联
DOI
高影响因子
Particuology
·
2021
·
IF 3.067
Jinbo Ouyang,Xiaohong Xing,Jian Chen,Limin Zhou,Zhirong Liu,Jerry Y.Y. Heng
Swift cooling crystallization of vanillin was investigated in water, ethanol, isopropanol and ethyl acetate. Morphology and polymorph evolution of vanillin were discussed in terms of solvent, supersaturation ratio and silica template. PXRD, DSC, FTIR and microscope were used to identify polymorphs of vanillin. Results showed that the nucleated polymorphs of vanillin depended largely on the solvent, supersaturation ratio and silica template. Low supersaturation ratios favor the nucleation of stable form I in water, and high supersaturation ratio exceeds 7 generating 100% metastable form II. However, if the supersaturation ratio is too high ( S >8), liquid–liquid phase separation will occur, and no crystals could be obtained. In other solvents such as ethanol, isopropanol and ethyl acetate, only form I was obtained. However, it should be noted that the morphology of form I prepared in ethanol, isopropanol and ethyl acetate is distinct from that obtained in water, the former is flake-like and the latter is rod-like. The nucleation of vanillin from different solution was also studied with the presence of SiO 2 , SiO 2 –NH 2 and SiO 2 −COOH templates, which did not change the nucleated polymorph of vanillin, but changed the nucleation and growth rate of stable form I.
研究领域:
化学工程
·
材料科学
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晶体学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Bingying Gao,Jinyao Cao,Chao Yao,Linqiang Mao
Advanced aerogel materials with lightweight, flame retardant, and rapid cooling properties are urgently needed as thermal insulators in harsh environments. Herein, Cr 2 O 3 − Al 2 O 3 aerogels (CrAAs) were fabricated through a simple method and an ambient pressure drying process. A large number of pores were produced in the microstructure of the sample by the carbonization of soluble starch during calcination. The porous structure decreases the density of the prepared CrAA (Cr 2 O 3 − Al 2 O 3 aerogel) to as low as 0.143 g cm −3 , and increases the thermal conductivity to as high as 0.125 W m −1 K −1 , indicating the good thermal dissipation and rapid cooling performance of the sample. The prepared CrAAs possess a variety of composite properties such as good flame retardancy, rapid cooling, and colour restore after flame is extinguished. Moreover, after being subjected to flame treatment at ∼ 1300 °C using a butane blowtorch for 5 min, the CrAAs can be rapidly cooled to about 39.2 °C in about 1–2 min. The mechanism of the rapid cooling property was herein analysed, and we anticipate the potential application of CrAAs in flame–retardant cooling coatings.
研究领域:
材料科学
·
热工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Materials Letters
·
2024
·
IF 9.6
Zaizheng Sun,Jinming Liu,Haiming Chen,Dongsheng Mao
With the in-depth exploration of extreme environments in polar, mountainous areas, and outer space, the demand for ultralow temperature resistant adhesives is increasing. However, for most adhesives used, represented by epoxy and acrylic resins, this is almost impossible due to their extensive intermolecular interaction and rigid three-dimensional (3D) network structure. Herein, an adhesive with a well-designed hard–soft phase separation structure has been developed in this work, which exhibits excellent bonding strength and debonding performance when bonded to metals (stainless steel and aluminum) and nonmetallic materials (polycarbonate) at −80 °C. The bonding strength and debonding energy with stainless steel reached 35.7 MPa and 61.16 kN/m, respectively, which is 5 times higher than those reported in the literature. Moreover, the adhesive exhibits good stability after 10 cycles of rapid cooling and heating between −196–50 °C. Finally, the mechanism behind the excellent bonding was verified, which stems from the strong polarity of the hard segments and the hardening of the soft segments.
研究领域:
材料科学
·
胶粘技术
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Wenqian Zheng,Lina Wang,He Jiao,Zhixin Wu,Qi Zhao,Tao Lin,Hude Ma,Zhilin Zhang,Xinye Xu,Jie Cao,Jiang Zhong,Jingkun Xu,Baoyang Lu
First-aid burn wound patches play an essential role in reducing mortality by preventing hyperthermia and resisting wound infection. However, existing products still suffer from inferior cooling performance, limited therapeutic effect, weaker wound protection, and/or high cost, which hinder their widespread application in market. Herein, we design and fabricate a cost-effective multilayered topological hydrogel-based first-aid burn wound patch (FBP) for rapid cooling, efficient anti-inflammation, and wound protection. Such a hydrogel patch is fabricated from a polyacrylamide-chitosan (PAAm-CS) hydrogel as the soft antibacterial layer integrated with a topological poly(vinyl alcohol)-chitosan (PVA-CS) hydrogel as the stretchable cooling layer, as well as thin polyethylene films as encapsulated layers to prevent dehydration. As-fabricated FBP exhibits a unique combination of intriguing mechanical, thermal, and biological properties, including softness (Young’s modulus of 83 kPa), stretchability (fracture stain over 106%), high thermal conductivity (0.54 W m −1 K −1 ), instant cooling, effective antibacterial activity (96.2% for S. aureus, 92.2% for E. coli), and excellent biocompatibility (94.04% cell viability at 20 mg mL −1 extract in 24 h). A second-degree scald rat model further demonstrates that fast-cooling and anti-inflammatory FBP can effectively reduce the tissue damage and inflammation levels by showing less edema formation and higher collagen/blood vessel ratios. With a set of these interesting performances, the FBP may be useful as a first-aid burn wound product to alleviate patients’ sufferings and even rescue more lives in critical situation.
研究领域:
材料科学
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生物医学工程
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伤口愈合
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热管理
·
抗菌材料
✓ 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）