CONSTRUCTION AND BUILDING MATERIALS
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2024
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IF 7.4
Zhipeng Zhu,Xiaoxue Song,Xiang Chi,Jingyao Zhao,Qiaofang Zhou,Antoni Sanchez‑Ferrer,Dengyun Tu,Wanli Cheng
Unilateral surface compression in wood presents notable benefits, including reduced wood volume loss and energy consumption, rendering a highly promising and extensive utilization. However, shortcomings in compressed wood arise due to unclear gas pressure, temperature, and moisture content distribution within the wood during hot pressing. In this paper, the temperature and pressure distribution were analyzed utilizing an optical fiber temperature and pressure measurement system within the wood during hot pressing. Moreover, the moisture content, stress and strain in each layer at the end of hot pressing were discussed extensively. The results showed that the wood surface layer (SL) and subsurface layer (SSL) maximum temperature values were similar even with different layer thicknesses. Under sealing conditions, SL and SSL temperatures were generally 6 ℃ to 7 ℃ higher compared to unsealing conditions. The gas pressure maximum value exhibited an opposite order, gradually transferring to the core layer (CL) and declining as the processing time extended. During compression treatment, moisture migrated from the hot end to the cold within the wood. The moisture content displayed significant differences between the middle and end parts of the wood under unsealed conditions, with the disparity becoming more pronounced further away from the hot end. The transition region of the compressed wood served as a stress concentration area, experiencing the highest levels of stress. The dense region followed with the second highest stress levels, while the un-densified region exhibited the least amount of stress. Under the same process parameters, the thickness had little influence on the distribution of dense layers.
研究领域:
木材科学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
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2024
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IF 5
Yecheng Wang,Danqi Sun
Fatigue has long been studied for many materials, but many aspects are not well understood. Our recent study of the distinct roles of crosslinks and entanglements in the synthesis-property relation of a polymer network under monotonic load leads to a fundamental question: how do crosslinks and entanglements affect the synthesis-property relation of a polymer network under cyclic load? Here we study the relation of synthesis and fatigue property of elastic soft materials without precut cracks. We prepare polyacrylamide hydrogels by free radical polymerization as a model system, and swell the hydrogels in water to equilibrium or to a certain amount of polymer content. The synthesis parameters include the crosslinker-to-monomer molar ratio and the water-to-monomer molar ratio in the precursor, as well as the polymer content in the hydrogel. Three series of hydrogels are prepared. For each hydrogel, the stress-stretch curve under cyclic stretch of various amplitudes and the number of cycles to rupture are measured, giving four properties: fatigue life, endurance stretch, endurance stress, and endurance work. When the crosslinker-to-monomer molar ratio in the precursor is high, the degree of network imperfection on average is low. When the water-to-monomer molar ratio in the precursor is low, the number of entanglements per polymer segment on average is large. We show that crosslinks decrease the susceptibility to fatigue and entanglements increase the endurance stress. By contrast, both crosslinks and entanglements negligibly affect the endurance stretch and the endurance work.
研究领域:
材料科学
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高分子科学
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
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2024
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IF 4.4
Hao-Jia Guo,Xiaodong Qiao,Ben-Xiang Hu,Shuangquan Liao,Ming-Chao Luo
The recycling of waste rubber (WR) is beneficial to the sustainable development of rubber industries. However, interactions among WR are weak, limiting the recycling of WR. In this work, our group designed bis-diazo compounds to promote interactions among WR for recycling through aliphatic C–H insertion strategies. Specifically, upon hot pressing, bis-diazo compounds produce bis-carbenes which react with C–H on the surface of WR by C–H insertions, and then we obtain recycled WR materials. As a result, stress–strain curves show that the strength of recycled WR increases steadily with the increase of bis-diazo compound loading, which has reached the level of butadiene styrene rubbers. Moreover, the introduced disulfide bonds endow recycled WR with reprocessability. Stress–relaxation experiments at different temperatures show that recycled WR with disulfide bonds have unique vitrimer viscoelastic properties. The feasibility of bis-diazo compounds to enhance interactions among WR through C–H insertions opens opportunities to recycle and reinvent industrial WR.
研究领域:
材料科学
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化学工程
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回收技术
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
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2024
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IF 7.6
Abdullrahman M. Al-Bishari,Tingting Liu,Jiatong Zhuang,Qihong Zhang,Jiaquan Chen,Yan Wang,Chuanyang Liu,Peng Gao,Jinsong Liu,Lei Lu
Advancements in guided bone regeneration (GBR) rely on the development of membranes that can effectively control drug delivery and facilitate bone repair. This study introduces a triple-layered multi-functional membrane (MFM), with each layer serving a specific release profile and function. These layers consist of Qk peptide, strontium (Sr), and vancomycin (Van) for angiogenesis, bone growth, and infection control. The MFM was meticulously designed to ensure sustained drug release kinetics and improved bone regeneration. The membrane morphology was analyzed via SEM, and its mechanical properties were measured via stress–strain curves. In vitro studies confirmed the controlled release of the agents for 21 days. These findings indicate significant enhancements needed for GBR, as supported by in vitro results. The synergy of the membrane's components contributes to a greater therapeutic impact. Furthermore, in vivo results further supported the exceptional performance of MFM in GBR. Within 5 days of implantation, notable improvements in revascularization were observed. After 1 month, micro-CT scans displayed accelerated bone regeneration, while the membrane effectively prevented bacterial growth within 3 days. The MFM/Van-Sr-Qk membrane shows excellent potential for advancing bone regeneration and GBR therapies, warranting further research and development in this promising field.
研究领域:
生物医学工程
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材料科学
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组织工程
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药学
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骨科
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
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2023
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IF 13.1
Mang Wu,Jianfei Ma,Xiankun Wu,Junsheng Yang,Zhongkai Wang
Recently, one of the challenges faced by autonomous self-healing materials is how to improve strength and toughness while maintaining rapid self-healing properties at ambient temperature. Herein, by integrating multi-scale dynamic physical networks that are hydrogen bonds , metal-coordination bonds, and dynamic crystalline domains in bio-based long-chain polyamides , a series of multi-scale elastomers (MSE n ) were obtained. The multi-scale dynamic physical networks endow elastomers with low initial modulus , outstanding nonlinear “J-shaped” stress-strain mechanoresponsive behavior, high tear-resistance, and good puncture properties. More importantly, the representative elastomers MSE 18 exhibit outstanding toughness (strength of 66.3 ± 1.84 MPa, elongation at break of 660 ± 17.28%, and toughness of 155 ± 4.32 MJ/m 3 ) and rapid autonomic self-healing properties (totally healed in 3 h at room temperature). The design concept indicates a promising direction for elastomers with ultra-tough mechanical properties and rapid room temperature self-healing behavior without external stimuli.
研究领域:
材料科学
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高分子化学
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机械工程
✓ 已验证
DOI
高影响因子
Regenerative Biomaterials
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2024
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IF 5.6
Nie Xiongfeng,Tang Yong,Wu Tengling,Zhao Xinrui,Xu Ziyang,Yang Rong,Sun Yage,Wu Bin,Han Quanhong,Hui Jingwen,Liu Wenguang
3D printing of high-strength natural polymer biodegradable hydrogel scaffolds simultaneously resembling the biomechanics of corneal tissue and facilitating tissue regeneration remains a huge challenge due to the inherent brittleness of natural polymer hydrogels and the demanding requirements of printing. Herein, concentrated aqueous solutions of gelatin and carbohydrazide modified alginate (Gel/Alg-CDH) are blended to form a natural polymer hydrogel ink, where the hydrazides in Alg-CDH are found to form strong hydrogen-bonds with the gelatin. The hydrogen-bonding-strengthened Gel/Alg-CDH hydrogel demonstrates an appropriate thickened viscosity and shear-thinning for extrusion printing. The strong hydrogen bonds contribute to remarkably increased mechanical properties of Gel/Alg-CDH hydrogel with a maximum elongation of over 400%. In addition, sequentially Ca2+-physical crosslinking and then moderately chemical crosslinking significantly enhance the mechanical properties of Gel/Alg-CDH hydrogels that ultimately exhibit an intriguing J-shaped stress-strain curve (tensile strength of 1.068 MPa and the toughness of 677.6 kJ/m2). The dually crosslinked Gel-Alg-CDH-Ca2+-EDC hydrogels demonstrate a high transparency, physiological swelling stability and rapid enzymatic degradability, as well as suturability. Growth factor and drug-loaded biomimetic bilayer hydrogel scaffold is customized via a multi-nozzle printing system. This bioactive bilayer hydrogel scaffold considerably promotes regeneration of corneal epithelium and stroma, and inhibits cornea scarring in rabbit cornea keratoplasty.
研究领域:
生物医学工程
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材料科学
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组织工程
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再生医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）