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【新文速递】2024年2月27日复合材料SCI期刊最新文章

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今日更新:Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇

Composites Part B: Engineering

An interface-integrated hydrogel for all-in-one flexible supercapacitor with excellent wide-temperature and self-healing properties

Ruiting Wang, Da Lei, Hang Zhang, Jianrong Liang, Zhihao Shang, Li Wan, Zhengzheng Li, Chuanling Si

doi:10.1016/j.compositesb.2024.111345

 

用于一体化柔性超级电容器的界面集成水凝胶,具有优异的宽温和自修复性能

With the rapid development of flexible energy storage devices, the abilities to withstand various of mechanical deformation and maintain stable electrochemical performance at different temperatures are two decisive factors that stand out in their applications. Herein, aniline containing 2-acrylamido-2methylpropane sulfonic acid sodium is polymerized in-situ on hydrogels with double cross-linked networks constructed by polyacrylamide, polyvinyl alcohol and quaternary ammonium salt of chitosan through electrostatic interaction, so as to obtain the PPHP-Na hydrogels for the construction of the all-in-one flexible supercapacitors. The PPHP-Na hydrogels can withstand a maximum of 544% tensile strain at tensile stress up to 601 kPa, and can maintain stable dissipation during stress-strain tensile cycles and recover quickly after cycling, exhibiting excellent mechanical properties. In addition, the optimal PPHP-Na hydrogel shows a high ionic conductivity of 65.6 mS cm−1. More importantly, as an all-in-one flexible energy storage device, the PPHP-Na supercapacitor shows high area capacitance of 250.75 mF cm−2, and can maintain relatively stable electrochemical performance at -40-80 °C and good self-healing property. This interface integrated strategy of all-in-one flexible supercapacitors with excellent and stable electrochemical performance constructed provides meaningful ideas for the development of flexible electronic devices.

随着柔性储能设备的快速发展,能够承受各种机械变形和在不同温度下保持稳定的电化学性能是其应用中的两大决定性因素。本文将含有2-丙烯酰胺基-2-甲基丙烷磺酸钠的苯胺通过静电作用原位聚合在由聚丙烯酰胺、聚乙烯醇和壳聚糖季铵盐构建的双交联网络水凝胶上,从而得到用于构建一体化柔性超级电容器的PPHP-Na水凝胶。PPHP-Na 水凝胶在拉伸应力高达 601 kPa 时可承受最大 544% 的拉伸应变,并能在应力-应变拉伸循环过程中保持稳定的耗散,在循环后迅速恢复,表现出优异的机械性能。此外,最佳 PPHP-Na 水凝胶的离子电导率高达 65.6 mS cm-1。更重要的是,作为一种一体化柔性储能器件,PPHP-Na 超级电容器显示出 250.75 mF cm-2 的高面积电容,并能在 -40-80 °C 温度下保持相对稳定的电化学性能和良好的自愈性。这种界面集成策略构建的一体化柔性超级电容器具有优异稳定的电化学性能,为柔性电子器件的发展提供了有意义的思路。


Composites Science and Technology

A data-driven model based on the numerical solution of the equivalent inclusion problem for the analysis of nonlinear short-fibre composites

Witold Ogierman

doi:10.1016/j.compscitech.2024.110516

 

基于等效包含问题数值解的数据驱动模型,用于分析非线性短纤维复合材料

The paper introduces a novel data-driven homogenization model developed for the computation of stress-strain curves for composites featuring arbitrary orientation distributions, aspect ratios, and volume fractions of fibres. The objective of the proposed model is to deliver both time-efficient and accurate results while taking into account a relatively small database. The database is generated through numerical solutions of the equivalent inclusion problem, encompassing results for predefined orientations and aspect ratios of the single inclusion (fibre). The database created for a specific matrix-fibre system can be employed by the surrogate model to predict outcomes for various cases involving different fibre configurations. The surrogate model comprises four key modules: aspect ratio interpolation, a discrete orientation averaging procedure involving a genetic algorithm, a spatial transformation procedure, and an iterative Mori-Tanaka scheme. The validity of the proposed data-driven model has been confirmed by comparing the obtained results with those acquired through analysis of the complex representative volume element (RVE) using Fast Fourier Transform (FFT)-based homogenization, as well as through comparisons with experimental results from the existing literature.

本文介绍了一种新颖的数据驱动均质化模型,用于计算具有任意取向分布、长宽比和纤维体积分数的复合材料的应力-应变曲线。所提模型的目标是在考虑到数据库相对较小的情况下,提供既省时又准确的结果。该数据库是通过对等效包含问题的数值求解生成的,包含单个包含体(纤维)的预定取向和长宽比的结果。代用模型可利用为特定基体-纤维系统创建的数据库来预测涉及不同纤维配置的各种情况的结果。代用模型包括四个关键模块:长宽比插值、涉及遗传算法的离散取向平均程序、空间变换程序和迭代森-田中方案。通过将所获得的结果与使用基于快速傅里叶变换(FFT)的均质化方法对复杂代表性体积元素(RVE)进行分析所获得的结果进行比较,以及与现有文献中的实验结果进行比较,证实了所提出的数据驱动模型的有效性。



 

来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform复合材料非线性化学电子UG材料储能
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首次发布时间:2024-11-06
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【新文速递】2024年3月1日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 3 篇Composite StructuresMultiband acoustic helical interface states in inverse-designed sonic crystals with glide symmetryYafeng Chen, Shuowei An, Zhihao Lan, Lei Fan, Liang An, Zhongqing Sudoi:10.1016/j.compstruct.2024.117994具有滑行对称性的反向设计声波晶体中的多波段声波螺旋界面态Acoustic topological insulators (ATIs) with topological states that are insensitive to defects and impurities offer a robust way to steer acoustic waves. However, current ATIs in square lattice only host topological interface states within one bulk bandgap, restricting their multiband applications. Here, we design the ATI, made of glide-symmetric sonic crystals (SCs), hosting multiband topological interface states within multiple bulk bandgaps. First, SCs restricted with glide and mirror symmetries are inversely designed to host multiple bulk bandgaps. Then, the ATI with multiband helical interface states is constructed by selecting two kinds of unit cells (UCs) from the inverse-designed SC and arranging them to form an interface. Both dual-band and triple-band ATIs are designed and experimentally validated. The total size of interface states hosted by the triple-band ATI is about 8.5 times of the record. Besides, by exploiting the mismatch of frequency windows of interface states at the horizontal and vertical interfaces, we realize acoustic demultiplexers for routing interface states. Our work suggests a route to engineering multiband ATIs, having promising applications in designing novel acoustic devices for multiband information processing and communication.声拓扑绝缘体(ATI)的拓扑态对缺陷和杂质不敏感,为声波的转向提供了一种稳健的方法。然而,目前方晶格的声学拓扑绝缘体只能在一个体带隙内承载拓扑界面态,限制了其多波段应用。在这里,我们设计了由滑行对称声波晶体(SCs)构成的 ATI,在多个体带隙内承载多频带拓扑界面态。首先,受限于滑行和镜像对称性的声波晶体被反向设计为承载多个体带隙。然后,从反向设计的 SC 中选择两种单元单元(UC),并将它们排列形成一个界面,从而构建出具有多带螺旋界面态的 ATI。我们设计了双波段和三波段 ATI,并进行了实验验证。三波段 ATI 所承载的界面状态总大小约为记录的 8.5 倍。此外,通过利用水平和垂直界面上界面状态频率窗口的不匹配,我们实现了用于路由界面状态的声学解复用器。我们的工作为多频带 ATI 的工程设计提供了一条途径,在设计用于多频带信息处理和通信的新型声学设备方面具有广阔的应用前景。Composites Part A: Applied Science and ManufacturingTailoring adherend surfaces for enhanced bonding in CF/PEKK composites: Comparative analysis of atmospheric plasma activation and conventional treatmentsCeren Yildirim, Hasan Ulus, Bertan Beylergil, Abdulrahman Al-Nadhari, Serra Topal, Mehmet Yildizdoi:10.1016/j.compositesa.2024.108101 定制粘合剂表面以增强 CF/PEKK 复合材料的粘合力:大气等离子活化与传统处理方法的比较分析Here, we propose the utilization of atmospheric plasma activation (APA), which outperforms peel-ply (PP) treatment and mechanical abrasion (MA) in achieving high-performance adhesively bonded carbon fiber/polyetherketoneketone (CF/PEKK) composites. This study covers several key aspects, including the chemical and morphological characterization of treated surfaces and mechanical performance assessments of single lap-joints (SLJs) under tensile and flexural loading conditions. In addition, in-situ acoustic emission (AE) monitoring is employed during tensile tests to determine dominant damage types and failure modes in the SLJs. Surface analysis shows that MA increases roughness, PP treatment decreases wettability, while APA enhances wettability by modifying the surface chemistry. Tensile and flexural tests reveal that APA-treated joints surpassed non-treated (NT) ones, with up to 5- and 7-times higher load-carrying performance, respectively, while fracture analysis suggests a shift from adhesive to cohesive failure. AE results show that increased AE events related to cohesive failure align with improved interface interactions.在此,我们提出了大气等离子活化(APA)技术,它在实现高性能粘合碳纤维/聚醚酮酮(CF/PEKK)复合材料方面优于剥离层(PP)处理和机械磨损(MA)。本研究涉及几个关键方面,包括处理表面的化学和形态特征以及拉伸和弯曲加载条件下单搭接接头(SLJ)的机械性能评估。此外,在拉伸试验中还采用了原位声发射(AE)监测,以确定 SLJ 中的主要损伤类型和失效模式。表面分析表明,MA 增加了粗糙度,PP 处理降低了润湿性,而 APA 则通过改变表面化学性质提高了润湿性。拉伸和弯曲试验表明,APA 处理过的接合点的承载性能超过了未处理(NT)的接合点,分别提高了 5 倍和 7 倍。AE 结果表明,与内聚破坏相关的 AE 事件增加与界面相互作用的改善相一致。Valorisation of waste pulp from materials recovery facility rejects for composite applicationsNatalia Herrera, Diego Freire Ordóñez, Andre N. Gaduan, Kanjanawadee Singkronart, Daniel Hayes, Dhivya Puri, Koon-Yang Leedoi:10.1016/j.compositesa.2024.108108 从材料回收设施的废渣中提取废纸浆用于复合材料的价值评估Waste pulp was recovered from MRF rejects, purified, processed into paper sheets and laminated with polylactide (PLLA) films. The purification process employed produced waste pulp of different qualities. The mechanical properties of the resulting waste pulp fibre-reinforced laminated PLLA composites was indifferent to the type of waste pulp treatment used. All composites showed significant improvements over neat PLLA, highlighting the viability of using waste pulp as a potentially cheap and sustainable reinforcement for polymers. Lifecycle assessment further showed that the composites possessed lower net global warming potential, as well as the end-point impact categories of human health and ecosystem quality compared to neat PLLA. This is due to the higher mechanical performance of the composites, which leads to higher weight saving of the functional unit. Our work paves the way for the use of pulp rejects from the recycling process for higher value applications, diverting them from landfill or incineration.从 MRF 废料中回收废纸浆,经过净化后加工成纸张,并与聚乳酸 (PLLA) 薄膜复合。所采用的净化工艺产生了不同质量的废纸浆。废纸浆纤维增强层压聚乳酸复合材料的机械性能与废纸浆处理类型无关。与纯聚乳酸相比,所有复合材料都有明显改善,这突出表明了使用废纸浆作为廉价且可持续的聚合物增强材料的可行性。生命周期评估进一步表明,与纯聚乳酸相比,复合材料的全球变暖净潜势以及对人类健康和生态系统质量的最终影响类别都较低。这是由于复合材料具有更高的机械性能,从而减轻了功能单元的重量。我们的工作为将回收过程中的纸浆废料用于更高价值的应用铺平了道路,使其免于填埋或焚烧。A finite element percolation tunneling approach on the electrical properties of carbon nanotube elastomer nanocomposite pressure sensorsAlireza Alidoust, Mojtaba Haghgoo, Reza Ansari, Mohammad Kazem Hassanzadeh-Aghdam, Sung-Hwan Jangdoi:10.1016/j.compositesa.2024.108111碳纳米管弹性体纳米复合材料压力传感器电特性的有限元渗流隧道法A flexible pressure sensor utilizing carbon nanotubes (CNTs) is investigated employing a finite element methodology to delve into its electro-mechanical behavior. The responsive nature of the three-dimensional representative volume element, containing impenetrable CNT cylinders within an insulating hyperelastic elastomeric cube, is simulated to capture its sensitivity to pressure. Considering applied pressure and updated percolation pathways, a multi-step approach is employed to assess piezoresistivity. Upon adjusting positions of CNTs within the deformed state using the finite element method, novel pathways are identified using the critical distance criterion for percolation paths that contribute to the resistance network. Simulation results demonstrate good agreement with experimental data for resistivity and piezoresistive sensitivity of different CNT elastomeric nanocomposites. The finite element method helps to analyze influences of nanotube volume fraction, geometrical properties, and orientational configurations on the critical distance percolation onset. Lower CNT contents yield more substantial relative resistance changes due to fewer percolating routes.本研究采用有限元方法对利用碳纳米管 (CNT) 的柔性压力传感器进行了研究,以深入探讨其电子机械行为。模拟了三维代表体积元素的响应特性,该元素在绝缘超弹性立方体中包含不可穿透的碳纳米管圆柱体,以捕捉其对压力的敏感性。考虑到施加的压力和更新的渗流路径,采用了一种多步骤方法来评估压阻率。使用有限元方法调整变形状态中 CNT 的位置后,利用临界距离标准确定了有助于形成电阻网络的渗流路径。模拟结果表明,不同 CNT 弹性纳米复合材料的电阻率和压阻灵敏度与实验数据十分吻合。有限元法有助于分析纳米管体积分数、几何特性和取向配置对临界渗流起始距离的影响。由于渗流路径较少,较低的碳纳米管含量会产生较大幅度的相对电阻变化。Fatigue life simulation of the impacted carbon/epoxy composite laminatesAlireza Pakravan, Fathollah Taheri-Behroozdoi:10.1016/j.compositesa.2024.108112受冲击碳/环氧复合材料层压板的疲劳寿命模拟The increasing use of composite materials in the aviation industry has led to a greater need to maintain composite structures’ safety against impact damage, especially when exposed to repetitive loading. Since experimental work can be challenging, proposing a simple and practical method of co-simulating composite laminates’ impact and fatigue behavior is crucial. This research presents composite and cohesive fatigue models based on the fundamental models of Shokrieh-Lessard and Turon. Additionally, two impact models with parameters consistent with these fatigue models are presented as well. Then, the impacted composite laminates are analyzed using a VUMAT that includes these models, and the results are compared to experimental data. The numerical analysis shows that the propagation patterns and shapes of different damage modes for impact and tension–tension fatigue are similar to experimental observations. However, for tension–compression, the simulation results differ partially from the tests. The tensile fatigue results showed that the impact had no significant effect on the specimen’s life. In contrast, a 2.1 J impact reduces specimens’ fatigue life for a maximum load of more than 40 % of the compressive strength, under tension–compression fatigue.随着复合材料在航空工业中的使用日益增多,人们更加需要保持复合材料结构的安全性,防止其受到冲击损坏,尤其是在承受重复载荷时。由于实验工作具有挑战性,因此提出一种简单实用的方法来共同模拟复合材料层压板的冲击和疲劳行为至关重要。本研究以 Shokrieh-Lessard 和 Turon 的基本模型为基础,提出了复合材料和内聚疲劳模型。此外,还介绍了与这些疲劳模型参数一致的两个冲击模型。然后,使用包含这些模型的 VUMAT 对受冲击的复合材料层压板进行分析,并将结果与实验数据进行比较。数值分析表明,冲击和拉伸疲劳的不同损伤模式的传播模式和形状与实验观察结果相似。然而,对于拉伸-压缩,模拟结果与试验结果存在部分差异。拉伸疲劳结果显示,冲击对试样的寿命没有明显影响。相反,在拉伸-压缩疲劳下,2.1 J 的冲击力会降低试样的疲劳寿命,最大载荷超过抗压强度的 40%。Carbon fibre reinforced bisphenol-A type SPEEK composite for water lubricated superlubricityMinsong Wu, Tao Hu, Jianyong Lan, Xiaolei Li, Chenhui Zhang, Jianbin Luodoi:10.1016/j.compositesa.2024.108113用于水润滑超润滑的碳纤维增强双酚 A 型 SPEEK 复合材料Polyether ether ketone (PEEK), as a high-performance engineering polymer, can be a promising material for water lubricated bearings. However, some modifications are imperative when it is widely employed in engineering. In this study, a novel bisphenol-A (BPA) type sulfonated polyether ether ketone (SPEEK-BPA) polymer was synthesized, and it was compounded with 10 wt% carbon fibre (SPEEK-BPA/10 %CF) to obtain a water lubricated material with ultralow friction coefficient (COF) and excellent wear resistance. The outstanding tribological properties of SPEEK-BPA/10 %CF was attributed to the adsorption of hydrated Na+ cations by –SO3¯ and the reinforcement of carbon fibre. The COF of SPEEK-BPA/10 %CF can be reduced as low as 0.009 when a 3 wt% NaCl solution was used as the lubricant at a low sliding speed (0.10 m/s). At the same time, the wear rate of SPEEK-BPA/10 %CF reached to a magnitude of 10-7 and 10-8 mm3/(Nm), which was much lower than commercial PEEK. Therefore, this friction-reducing and anti-wear composite has great potential to realize a water lubricated bearing with low noise and superlubricity.聚醚醚酮(PEEK)作为一种高性能工程聚合物,是一种很有前途的水润滑轴承材料。然而,当它被广泛应用于工程领域时,一些改性措施势在必行。本研究合成了一种新型双酚-A(BPA)型磺化聚醚醚酮(SPEEK-BPA)聚合物,并将其与 10 wt%的碳纤维(SPEEK-BPA/10 %CF)复合,从而获得了一种具有超低摩擦系数(COF)和优异耐磨性的水润滑材料。SPEEK-BPA/10 %CF 的出色摩擦学特性归功于 -SO3¯ 吸附水合 Na+ 阳离子和碳纤维的增强。在低滑动速度(0.10 m/s)下使用 3 wt% 的 NaCl 溶液作为润滑剂时,SPEEK-BPA/10 %CF 的 COF 可降至 0.009。同时,SPEEK-BPA/10 %CF 的磨损率分别达到 10-7 和 10-8 mm3/(Nm),远低于商用 PEEK。因此,这种减摩抗磨复合材料在实现低噪音、超润滑的水润滑轴承方面具有巨大潜力。Composites Part B: EngineeringNovel polybutadiene rubber with long Cis-1,4 and syndiotactic vinyl segments (CVBR) for high performance sidewall of all-steel giant off-the-road tireHan Zhu, Ming Tang, Yan-qin Hao, Zhi-feng Zhou, Du Sun, Pei-fu Yu, Yi-xian Wudoi:10.1016/j.compositesb.2024.111349 具有长顺式-1,4 和辛二乙烯基段的新型聚丁二烯橡胶 (CVBR),适用于高性能全钢巨型越野轮胎胎侧The novel polybutadiene rubbers (CVBR) carrying 88–97% of long cis-1,4 polybutadiene segments (cis-PB, cis-1,4 content >98.3%) and 3–12% of long syndiotactic1,2-polybutadiene segments (sPB, 1,2 content >87.0%) could be successfully synthesized via in-situ coordination polymerizations of butadiene in hexane in our lab and also be scaled up via continuous polymerization process in pilot (scale: 200 t/a). The natural rubber (NR)-based compound formulations containing different contents of CVBR, and carbon black (CB) fillers were developed and the optimized NR/CVBR/CB vulcanizates with 40% of CVBR were manufactured for the sidewall of all-steel giant off-the-road tire. The storage modulus of NR/CVBR/CB compounds and the elastic modulus, tensile strength and tear strength of NR/CVBR/CB vulcanizates could be remarkably increased by increasing CVBR content. The crack generation and growth could be effectively restricted due to both the fast relaxation, the rigid polymer-filler interface, synergistic effect of high cis-polybutadiene and crystalline 1,2-polybutadiene particles on the strain-induced crystallization behaviors of rubber matrix. The heat build-up of NR/CVBR/CB vulcanizates could be greatly reduced by introduction of cis-PB segments in CVBR for the easy mobility and low hysteresis of macromolecular chains. The NR/CVBR/CB vulcanizates with high strength and elastic modulus, low heat build-up and high flex fatigue crack resistance would meet the requirement for high performance sidewall in manufacturing giant all-steel off-the-road tires.我们实验室通过丁二烯在己烷中的原位配位聚合,成功合成了含有 88-97% 长顺式-1,4 聚丁二烯段(顺式-PB,顺式-1,4 含量大于 98.3%)和 3-12% 长辛二烯-1,2 聚丁二烯段(辛二烯-SPB,1,2 含量大于 87.0%)的新型聚丁二烯橡胶(CVBR)。开发了含有不同含量 CVBR 和炭黑(CB)填料的天然橡胶(NR)基复合配方,并生产了含有 40% CVBR 的优化 NR/CVBR/CB 硫化胶,用于全钢巨型非公路轮胎的胎侧。随着 CVBR 含量的增加,NR/CVBR/CB 复合物的储存模量以及 NR/CVBR/CB 硫化胶的弹性模量、拉伸强度和撕裂强度都有显著提高。由于快速松弛、刚性聚合物-填料界面、高顺式聚丁二烯和结晶性 1,2 聚丁二烯颗粒对橡胶基体应变诱导结晶行为的协同作用,裂纹的产生和生长可得到有效限制。通过在 CVBR 中引入顺式聚丁二烯段,可大大降低 NR/CVBR/CB 硫化胶的发热量,从而实现大分子链的易流动性和低滞后性。NR/CVBR/CB 硫化物具有高强度和弹性模量、低热积聚和高抗挠曲疲劳开裂性能,可满足制造巨型全钢非公路轮胎对高性能胎侧的要求。Synergistic osteogenesis and angiogenesis in promoting bone repair by levistolide A-induced smad pathway activationZhengzhe Han, Ang Li, Yuanman Yu, Kai Dai, Wenjing Yin, Xiaolin Li, Jing Wang, Min Yu, Xin Qi, Qi Lidoi:10.1016/j.compositesb.2024.111348 左旋A诱导的smad通路激活促进骨修复的协同成骨和血管生成作用Bone defects are a prevalent issue in orthopedics clinics, and tissue engineering offers a new hope for treatment. Angiogenesis ability is indispensable during the healing process of bone defects, and the combination of osteogenesis and angiogenesis ability is essential in treating bone defects effectively. Herein, with the aid of traditional Chinese medicine, we have discovered that Levistolide A, a component of Angelica sinensis, has the potential in treating bone defects due to its angiogenesis ability. In vitro experiments have demonstrated its ability to promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells. Levistolide A can also indirectly promote the proliferation and recruitment of endothelial cells. Our proteomics analysis revealed that Levistolide A inhibited skp-1 and activated the Smad pathway to exert its effect on bone marrow mesenchymal stem cells. In vivo experiments proved that combined with a bioactive material scaffold, Levistolide A is used to effectively repair rat skull defects. Based on the above results, we have discovered a small molecule, which is cheap and stable. It can also provide hope for treatment of a large number of clinical patients.骨缺损是骨科临床中普遍存在的问题,组织工程为治疗带来了新的希望。在骨缺损的愈合过程中,血管生成能力是不可或缺的,而要想有效治疗骨缺损,就必须将成骨能力和血管生成能力结合起来。在此,我们借助传统中医药发现,当归中的成分左旋内酯 A 因其血管生成能力而具有治疗骨缺损的潜力。体外实验证明,它能够促进骨髓间充质干细胞的增殖和成骨分化。左旋内酯 A 还能间接促进内皮细胞的增殖和募集。我们的蛋白质组学分析表明,左旋A抑制skp-1,激活Smad通路,从而对骨髓间充质干细胞产生作用。体内实验证明,结合生物活性材料支架,左旋内酯 A 可有效修复大鼠颅骨缺损。基于上述结果,我们发现了一种廉价、稳定的小分子。它还能为大量临床患者的治疗带来希望。Composites Science and TechnologyMechanical characterization of polymer-grafted graphene PEG nanocomposites using molecular dynamicsCátia Guarda, Bruno Faria, José N. Canongia Lopes, Nuno Silvestredoi:10.1016/j.compscitech.2024.110514 利用分子动力学分析聚合物接枝石墨烯 PEG 纳米复合材料的力学特性It is known that most polymers exhibit poor interfacial compatibility with graphene sheets. Modification of graphene's surface by functionalization with small polymer chains from the same building blocks as the matrix polymer improves the compatibility of graphene in polymeric materials. In this paper, the mechanical behaviour of polyethylene glycol (PEG) nanocomposites with graphene grafted with polymeric chains under tensile and compression is investigated using molecular dynamics. The influence of the functional groups (-NH2 and –OH) that bond the polymer chain to graphene is analysed. It is found that the system containing the –NH2 functional group showed lower mechanical properties than the system containing the –OH functional group. The mechanical properties of five PEG-nanocomposites are investigated: PEG/G, PEG/GNH-1PEG-S, PEG/GNH-2PEG-L, PEG/GNH-1PEG-S-NH2, PEG/GO-1PEG-S. The radius distribution function values and the variation of interfacial interaction energy are also examined. It is shown that functionalization of the graphene sheet increases the magnitude of the interaction energy, and it also reveals higher adhesion between graphene surface and PEG matrix. It is found that the mechanical properties of PEG are mostly improved in the longitudinal direction (reinforcement up to 43 %). Despite the high interaction between the nanofiller and PEG matrix, the low intrinsic properties of the nanofiller, namely Young's modulus, as well as the rupture of the graphene sheet during the deformation process deteriorated the mechanical properties of the nanocomposite. The presence of polymeric chains grafted to graphene improves the adhesion between the graphene surface and the polymeric matrix but decreases its mechanical properties.众所周知,大多数聚合物与石墨烯薄片的界面相容性较差。通过与基体聚合物相同结构单元的小聚合物链对石墨烯表面进行功能化改性,可以改善石墨烯在聚合物材料中的相容性。本文采用分子动力学方法研究了石墨烯接枝聚合物链的聚乙二醇(PEG)纳米复合材料在拉伸和压缩条件下的机械性能。分析了将聚合物链与石墨烯结合的官能团(-NH2 和 -OH)的影响。研究发现,含有 -NH2 官能团的体系比含有 -OH 官能团的体系显示出更低的机械性能。研究了五种 PEG 纳米复合材料的机械性能:PEG/G、PEG/GNH-1PEG-S、PEG/GNH-2PEG-L、PEG/GNH-1PEG-S-NH2、PEG/GO-1PEG-S。此外,还研究了半径分布函数值和界面相互作用能的变化。结果表明,石墨烯片层的功能化增加了相互作用能的大小,同时也显示出石墨烯表面与 PEG 基质之间更高的粘附性。研究发现,PEG 的机械性能主要在纵向得到改善(增强率高达 43%)。尽管纳米填料和 PEG 基体之间的相互作用很强,但纳米填料的固有特性(即杨氏模量)较低,而且在变形过程中石墨烯片会破裂,这些都降低了纳米复合材料的机械特性。接枝到石墨烯上的聚合物链的存在改善了石墨烯表面与聚合物基体之间的粘附性,但降低了其机械性能。Flexible phase change composites based on hierarchically porous polypyrrole scaffold for broad-band solar absorption and efficient solar-thermal-electric energy conversionYu-long Liu, Zi-cheng Tang, Zi-jie Huang, Wan-jun Jiang, Ting-yu Zhu, Jie Chen, Jing-hui Yang, Xiao-dong Qi, Yong Wangdoi:10.1016/j.compscitech.2024.110519 基于分层多孔聚吡咯支架的柔性相变复合材料,用于宽带太阳能吸收和高效太阳能-热能-电能转换Phase change materials (PCMs) with thermal energy storage property are vital in solar-thermal energy conversion and utilization systems. However, low thermal conductivity, low light absorption, and severe brittleness are major application-hindering factors. In this work, paraffin wax (PW) was vacuum impregnated into poly(dimethylsiloxane) (PDMS)/boron nitride (BN)/polypyrrole (PPy) foam to create flexible phase change composites (PCCs) with excellent thermal conductivity and solar-thermal energy conversion efficiency. The PDMS/BN/PPy foams were successfully prepared via the sugar template and chemical vapor deposition methods. The PDMS/BN/PPy/PW PCCs exhibited excellent phase change latent heat of 172 J·g−1 and dimensional retention ratio of 98.91%. The continuous BN network imparted the PCCs with enhanced thermal conductivity of 0.43 W m−1 K−1. Meanwhile, the flexible PCCs were capable of being elastically deformed and closely adhered to the rough surface, thus further improving the heat transfer efficiency. More importantly, the wrinkled PPy and the hierarchical porous structure improved light absorption by extending the optical path for multiple reflections, maintaining an outstanding solar-thermal energy conversion efficiency of 91.9%. A solar-thermal-electric energy conversion (STEEC) system was constructed to display the potential of PCCs to generate clean energy. PCCs could output a current of 84.7 mA and support the rotation of a fan for 243 s, even without light irradiation. This study provides a facile approach to preparing multi-functional PCCs, showing the advantages in the rapid collection and storage of solar energy.具有热能储存特性的相变材料(PCMs)在太阳能-热能转换和利用系统中至关重要。然而,低热导率、低光吸收率和严重的脆性是阻碍其应用的主要因素。在这项研究中,将石蜡(PW)真空浸渍到聚(二甲基硅氧烷)(PDMS)/氮化硼(BN)/聚吡咯(PPy)泡沫中,制备出具有优异导热性和太阳热能转换效率的柔性相变复合材料(PCC)。通过糖模板法和化学气相沉积法成功制备了 PDMS/BN/PPy 泡沫。PDMS/BN/PPy/PW PCCs 的相变潜热高达 172 J-g-1,尺寸保持率为 98.91%。连续的 BN 网络使 PCC 的热导率提高到 0.43 W m-1 K-1。同时,柔性 PCC 还能弹性变形并紧密附着于粗糙表面,从而进一步提高了传热效率。更重要的是,起皱的聚丙烯腈和分层多孔结构通过延长多次反射的光路改善了光吸收,从而保持了 91.9% 的出色的太阳能-热能转换效率。为了展示 PCC 产生清洁能源的潜力,我们建造了一个太阳能-热能-电能转换(STEEC)系统。即使在没有光照射的情况下,PCC 也能输出 84.7 mA 的电流,并支持风扇转动 243 s。这项研究提供了一种制备多功能 PCC 的简便方法,显示了其在快速收集和储存太阳能方面的优势。Thin and ultra-broadband electromagnetic absorption carbonyl iron-based metamaterial via multiscale synergic dielectric-magnetic designBo Huang, Fang Ye, Yuqiang Liu, Jie Liang, Yuchen Cao, Laifei Chengdoi:10.1016/j.compscitech.2024.110509 通过多尺度介电-磁协同设计实现超宽带薄电磁吸收羰基铁基超材料Thin and ultra-broadband electromagnetic wave (EMW) absorption material is essential in the fields of electromagnetic compatibility and radiation protection. Unfortunately, conventional materials are difficult to achieve low frequency EMW absorption such as 2–4 GHz at a limited thickness. Herein, a multiscale design strategy is presented to overcome this shortcoming. Carbonyl iron particle was used as the starting material. Firstly, microstructure modification from spherical morphology (SCIP) to flake one (FCIP) via a ball milling process was used to improve CIP's electromagnetic properties. Afterthat, macroscopic electromagnetic metastructure with the FCIP/polyurethane (PU) composite units was designed and its geometrical configuration was optimized. Through the multiscale design, an effective absorption in 2∼40 GHz was achieved at a thickness of merely 5 mm, surpassing most of the reported metamaterials. The broadband absorption mechanism was deciphered by CST simulation, which includes the synergic low-frequency absorption contributed by the FCIP/PU composite with delicate dielectric/magnetic synergistic property and the optimized impedance matching in broadband frequency caused by the well-designed metastructure. Our study provides valuable insights for the development of thin and ultra-broadband-absorbing material.薄型超宽带电磁波(EMW)吸收材料在电磁兼容和辐射防护领域至关重要。遗憾的是,传统材料很难在有限的厚度内实现 2-4 GHz 等低频电磁波吸收。本文提出了一种多尺度设计策略来克服这一缺陷。以羰基铁颗粒为起始材料。首先,通过球磨工艺将微观结构从球形形态(SCIP)改变为片状形态(FCIP),以改善 CIP 的电磁特性。随后,设计了 FCIP/聚氨酯(PU)复合单元的宏观电磁结构,并对其几何配置进行了优化。通过多尺度设计,在厚度仅为 5 毫米的情况下实现了 2∼40 GHz 的有效吸收,超过了大多数已报道的超材料。通过 CST 仿真破译了宽带吸收机制,其中包括具有微妙介电/磁协同特性的 FCIP/PU 复合材料带来的低频协同吸收,以及精心设计的超材料结构带来的宽带频率下的优化阻抗匹配。我们的研究为开发薄型超宽带吸收材料提供了宝贵的启示。来源:复合材料力学仿真Composites FEM

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