Composites Part B: Engineering最新文献_第5页

Drug-free extracellular vesicles: A spatiotemporally controlled release engineering strategy for osteogenesis and anti-inflammatory niches in rotator cuff regeneration 无药物细胞外囊泡：用于肩袖再生中骨生成和抗炎龛的时空控制释放工程策略

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111928

Guoyang Zhang , Dingyi Shi , Yiyao Wei , Mingqi Wang , Haohan Wang , Zhiqi Lin , Haihan Gao , Weixuan Lin , Hanyi Wang , Yonglin Guo , Yingyu Ge , Yi Lin , Yiwen Jiang , Xiaoyu Yan , Yuhao Kang , Liren Wang , Jinzhong Zhao , Weiyang Ying

Natural small-molecule drugs have promising potential to promote tissue regeneration in various fields. Therefore, maximizing drug efficiency while minimizing potential side effects is imperative. Peiminine, a natural product extracted from natural Fritillaria, is one of small-molecule drugs in the field of bone regeneration due to its good bone-promoting and anti-inflammatory abilities. However, its application is limited by a lack of biological activity, poor biocompatibility at high concentrations, and difficulty in achieving long-term slow-release and therapeutic effects. Extracellular vesicles (EVs) produced by preconditioned cells are considered to have special biological functions, and their potential to further retain, buffer, and transmit drug effects and expand the therapeutic effect has been widely studied. Thus, our study provides a drug-free bioengineering strategy by preconditioning bone marrow mesenchymal stem cells (BMSC) with Peiminine, then EVs, secreted as Peim-EVs, were extracted and combined with a decellularized extracellular matrix (dECM). The final EVs-dECM system with a spatiotemporally controlled release system was formed. In vitro studies demonstrated that Peim-EVs solved the problem of Peiminine biocompatibility and exhibited osteogenic and anti-inflammatory effects, which may be related to PI3K/AKT, MAPK/NF-κB, and Hippo signaling pathways. An in vivo model of rotator cuff injury in rats also showed that EVs-dECM had a good effect on rotator cuff repair. Combined with engineering strategy, this study provides verification and scenario expansion for drug application, especially for drug-free strategies that retain the biological effects of drugs, and has broad significance.

天然小分子药物在促进各领域的组织再生方面具有广阔的前景。因此，在最大限度地提高药物效率的同时减少潜在的副作用势在必行。从天然鱼腥草中提取的天然产物 Peiminine 具有良好的促骨和抗炎能力，是骨再生领域的小分子药物之一。然而，由于缺乏生物活性、高浓度时生物相容性差、难以实现长期缓释和治疗效果等原因，其应用受到了限制。由预处理细胞产生的细胞外囊泡 (EVs) 被认为具有特殊的生物功能，其进一步保留、缓冲和传递药物作用并扩大治疗效果的潜力已被广泛研究。因此，我们的研究提供了一种无药生物工程策略，即用培微宁预处理骨髓间充质干细胞（BMSC），然后提取其分泌的 EVs（即培微宁-EVs），并将其与脱细胞细胞外基质（dECM）相结合。最终形成了具有时空控制释放系统的 EVs-dECM 系统。体外研究表明，Peim-EVs 解决了 Peiminine 的生物相容性问题，并具有成骨和抗炎作用，这些作用可能与 PI3K/AKT、MAPK/NF-κB 和 Hippo 信号通路有关。大鼠体内肩袖损伤模型也表明，EVs-dECM 对肩袖修复有良好效果。结合工程策略，该研究为药物应用，尤其是保留药物生物效应的无药策略提供了验证和场景拓展，具有广泛的意义。

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引用次数: 0

The nitriding treatment of ternary nanofibers toward outstanding electromagnetic wave absorption performance 氮化处理三元纳米纤维以实现出色的电磁波吸收性能

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111922

Xiangwei Meng , Shuting Zhang , Meijie Yu , Chengguo Wang

Beneficial from the high electrical conductivity and remarkable chemical stability, transition metal nitrides have attracted widespread attention in the employment of electromagnetic wave absorption. Toward this end, Fe₄N/zirconium dioxide/carbon nanofibers composited absorber was triumphantly prepared by the combination of electrospinning, carbonization, and subsequent nitridation. After undergoing the nitriding treatment, the emergency of Fe₄N with superior electromagnetic properties, the introduction of more defects and functional groups, and the synergistic effect between each component would dramatically intensify multiple loss mechanisms, optimize the impedance matching, and improve the wave absorbing properties. Ultimately, the ternary fibrous nanocomposite realized the minimum reflection loss of −63.7 dB at 12.5 GHz with corresponding matching thickness of 2.2 mm, and an ultrabroad bandwidth up to 7.0 GHz. Therefore, this work substantiated the promising potential of Fe₄N in the practical application of microwave absorption, and shed light on the exploitation of a new generation metal nitrides-based wave absorbents.

过渡金属氮化物具有高导电性和出色的化学稳定性，因此在电磁波吸收领域受到广泛关注。为此，我们采用电纺丝、碳化和氮化工艺，成功制备出了Fe4N/二氧化锆/碳纳米纤维复合吸波材料。经过氮化处理后，具有优异电磁特性的 Fe4N 的紧急加入、更多缺陷和官能团的引入以及各组分之间的协同效应将显著强化多种损耗机制、优化阻抗匹配并改善吸波特性。最终，三元纤维纳米复合材料在 12.5 GHz 频率下实现了-63.7 dB 的最小反射损耗，相应的匹配厚度为 2.2 mm，超宽带宽可达 7.0 GHz。因此，这项工作证实了 Fe4N 在微波吸收实际应用中的巨大潜力，并为开发新一代基于金属氮化物的吸波材料提供了启示。

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引用次数: 0

Achieving excellent thermal transport in diamond/Cu composites by breaking bonding strength-heat transfer trade-off dilemma at the interface 通过打破界面上的结合强度-传热权衡困境，在金刚石/铜复合材料中实现优异的热传输性能

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111925

Guo Chang , Shuang Zhang , Kaiyun Chen , Wei Zhang , Liang Li , Yongjian Zhang , Haoran Peng , Dongxiao Kan , Luhua Wang , Hailong Zhang , Wangtu Huo

The heat transport enhancement of diamond/Cu composites, a new generation of thermal management materials, is trapped in the bonding strength-heat transfer trade-off dilemma at the interface due to the noticeable difference in physical and chemical properties between Cu and diamond. Herein, we propose a new strategy combining ultrathin interface modification and low-temperature high-pressure (LTHP) sintering process to prepare the diamond/Cu composites. With a suitable coefficient of thermal expansion (CTE) of <10 ppm/K, the obtained diamond/Cu composites exhibit an outstanding thermal conductivity (k) value of 763 W/m K, over 90 % of the theoretical prediction of the differential effective medium (DEM) model. Meanwhile, using a lower diamond volume fraction (45 % vs. 50%–70 %), the k value is higher than those by conventional powder metallurgy, meaning a substantial reduction in the cost by reducing diamond filler content. For such a highly mismatched diamond/Cu interface, we maintain a high bonding strength by lowering the thermal stress damage while achieve a high thermal conductance (G) of 93.5 MW/m² K by minimizing the heat transfer obstacles. The prepared interface structure is a diamond/TiC/CuTi₂/Cu configuration, where the two possible heat transfer bottlenecks (the diamond/TiC interface and the TiC/CuTi₂ interlayer) are no longer limiting factors on the overall interface. The successful resolution to the interfacial heat transfer problem is responsible for the superior thermal transport performance of the composites. This work deals with the critical challenge for the diamond/Cu composites and offers deep insight into the improvement mechanisms of thermal transfer. The proposed strategy can be generalized to the integration of highly mismatched interfaces widely present in other composites or thermal management systems.

金刚石/铜复合材料是新一代热管理材料，但由于铜和金刚石的物理和化学性质存在明显差异，其热传导性能的提高受困于界面处的结合强度-热传导权衡难题。在此，我们提出了一种结合超薄界面改性和低温高压（LTHP）烧结工艺制备金刚石/铜复合材料的新策略。在合适的热膨胀系数（CTE）（10 ppm/K）条件下，获得的金刚石/铜复合材料的热导率（k）值达到 763 W/m K，超过微分有效介质（DEM）模型理论预测值的 90%。同时，使用较低的金刚石体积分数（45% 对 50%-70%），其 k 值高于传统粉末冶金法的 k 值，这意味着通过减少金刚石填料含量可大幅降低成本。对于这种高度不匹配的金刚石/铜界面，我们通过降低热应力破坏来保持较高的结合强度，同时通过最大限度地减少传热障碍来实现 93.5 MW/m2 K 的高热导率 (G)。制备的界面结构为金刚石/TiC/CuTi2/Cu 配置，其中两个可能的传热瓶颈（金刚石/TiC 界面和 TiC/CuTi2 夹层）不再是整个界面的限制因素。界面传热问题的成功解决是复合材料具有优异热传导性能的原因。这项研究解决了金刚石/铜复合材料所面临的关键挑战，并对热传递的改进机制提出了深刻见解。所提出的策略可以推广到其他复合材料或热管理系统中广泛存在的高度不匹配界面的集成。

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引用次数: 0

Damage mechanisms of SiC fibers and BN interphase in SiCf/SiC composites during NITE process NITE 工艺过程中 SiCf/SiC 复合材料中 SiC 纤维和 BN 相间的损伤机理

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111923

Yu Zhang , Xu Shen , Qin Ma , Shuang Mu , Shaoming Dong , Jinshan Yang

In this work, the mechanical behavior of NITE-SiC_f/SiC composites, accompanied by the damage mechanisms of SiC fibers and BN interphase during NITE process, are investigated. The results show that the fracture characteristic of NITE-SiC_f/SiC composite is transformed from quasi-ductile mode to brittle mode with the elevating temperature, as well as severe damage of SiC fiber and BN interphase. The damage of SiC fibers is originated from high temperature, sintering aids corrosion and matrix compression. High temperature and sintering aids diffusion lead to the grain growth and strength degradation of SiC fibers. The damage of BN interphase is caused by the sintering aids corrosion, mainly the reaction of Al₂O₃, and matrix compression. The stress distribution is simulated via finite element analysis proving that up to 17.5 GPa and 17.0 GPa stress originated from matrix shrinkage during sintering process is applied to the fiber and interphase respectively, making the fiber deformation and interphase fragmentation. The degraded fiber strength and destroyed interphase structure weaken the load-bearing capacity and crack deflection ability, causing degradation of mechanical properties and reliability of composites. This work helps to comprehensively understand and optimize the properties of SiC_f/SiC composites prepared by NITE process.

本文研究了 NITE-SiCf/SiC 复合材料的力学行为，以及 NITE 过程中 SiC 纤维和 BN 相间层的损坏机制。结果表明，随着温度的升高，NITE-SiCf/SiC 复合材料的断裂特征从准韧性模式转变为脆性模式，SiC 纤维和 BN 相间层也发生了严重破坏。碳化硅纤维的损坏源于高温、烧结辅助腐蚀和基体压缩。高温和烧结助剂扩散导致碳化硅纤维晶粒长大和强度下降。BN 相间层的损坏是由烧结辅助腐蚀（主要是 Al2O3 反应）和基体压缩造成的。通过有限元分析模拟的应力分布证明，烧结过程中基体收缩产生的高达 17.5 GPa 和 17.0 GPa 的应力分别作用于纤维和相间层，导致纤维变形和相间层破碎。纤维强度的降低和相间结构的破坏削弱了复合材料的承载能力和裂纹变形能力，导致复合材料的力学性能和可靠性下降。这项工作有助于全面了解和优化采用 NITE 工艺制备的 SiCf/SiC 复合材料的性能。

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引用次数: 0

Unleashing the elastocaloric cooling potential of 3D-printed NiTi alloy with heterogeneous microstructures and Ni4Ti3 nanoparticles 释放具有异质微结构和 Ni4Ti3 纳米颗粒的 3D 打印镍钛合金的弹性冷却潜力

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111918

Jianbin Zhan , Ruijin Ma , Liang Zhu , Jiahui Fang , Kun Li , David Z. Zhang , Lawrence E. Murr

Toward the development of elastocaloric (eC) refrigeration applications, this study examines how Ni₄Ti₃ nanoparticles improve the eC properties of laser powder bed-fused (LPBF) NiTi alloys, with a focus on the formation of a NiTi/Ni₄Ti₃ nanocomposite. The LPBF-produced microstructure offers significant advantages: i) a heterogeneous grain structure that provides complementary benefits—fine grains offer higher deformation resistance while coarse grains initiate phase transformation (PT) earlier, releasing more latent heat; ii) a strong <001>//building direction texture that enhances recoverability. However, these benefits are partially limited by grain boundary slip during PT, leading to lower cooling efficiency and increased energy dissipation in as-built NiTi alloys. To address these issues, Ni₄Ti₃ nanoparticles are introduced through aging treatment, forming a composite structure that strengthens grain boundaries. Given the challenges of applying severe plastic deformation to 3D-printed components, this approach may offer a more practical solution. The study also reveals that Ni₄Ti₃ nanoparticles contribute to: 1) reducing Ni content in the matrix, increasing lattice size and enthalpy, which enhances the temperature drop (ΔT_ad); and 2) promoting R phase formation, which hinders the B2↔B19’ PT, reducing energy dissipation and improving the coefficient of performance (COP_mat). The balance of these effects depends on nanoparticle size, with smaller particles (∼5–12 nm) amplifying the second effect, while larger particles (∼130 nm) increase the first effect. At 350 °C aging, the optimized nanocomposite exhibits a maximum COP_mat of 15 and ΔT_ad of 14K, representing a 163 % improvement over the as-built alloy. This work highlights the potential of NiTi composites in 3D-printed eC components.

为了开发弹性制冷（eC）应用，本研究探讨了 Ni4Ti3 纳米粒子如何改善激光粉末床熔化（LPBF）镍钛合金的 eC 特性，重点是镍钛/Ni4Ti3 纳米复合材料的形成。LPBF 生产的微观结构具有以下显著优势：i) 异质晶粒结构提供了互补优势--细晶粒具有更高的抗变形能力，而粗晶粒更早启动相变 (PT)，释放出更多潜热；ii) 强<001>//构建方向纹理提高了可回收性。然而，这些优点在一定程度上受到 PT 期间晶界滑移的限制，导致冷却效率降低，坯料镍钛合金的能量耗散增加。为了解决这些问题，通过时效处理引入了 Ni4Ti3 纳米粒子，形成了一种可强化晶界的复合结构。考虑到对 3D 打印部件施加剧烈塑性变形所面临的挑战，这种方法可能会提供一种更实用的解决方案。研究还发现，Ni4Ti3 纳米粒子有助于1）减少基体中的镍含量，增加晶格尺寸和焓，从而提高温降（ΔTad）；2）促进 R 相形成，阻碍 B2↔B19' PT，减少能量耗散，提高性能系数（COPmat）。这些效应的平衡取决于纳米颗粒的大小，较小的颗粒（5～12 nm）会放大第二种效应，而较大的颗粒（130 nm）会增加第一种效应。在 350 °C 老化条件下，优化纳米复合材料的最大 COPmat 值为 15，ΔTad 值为 14K，与原合金相比提高了 163%。这项工作凸显了镍钛复合材料在三维打印 eC 组件中的潜力。

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引用次数: 0

Temperature-controlled in-situ construction of composition-tunable nanoparticle-decorated SOFC cathodes with enhanced oxygen reduction kinetics and CO2 tolerance 温控原位构建成分可调的纳米粒子装饰 SOFC 阴极，增强氧还原动力学和二氧化碳耐受性

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111917

Chuangang Yao , Baixi Xia , Haixia Zhang , Haocong Wang , Wenwen Zhang , Xiaoshi Lang , Kedi Cai

High oxygen reduction reaction (ORR) catalytic activity and CO₂ resistance of the cathode are fundamental to the commercial application of solid oxide fuel cells (SOFCs). Therefore, we develop a temperature-driven reduction-reoxidation strategy to in-situ construct heterostructured perovskite cathodes decorated with different nanoparticles by controlling the reduction temperature. For (Pr_0.4Sr_0.6)_0.95Co_0.2Fe_0.8-xNi_xO_3-δ (PSCFN, x = 0.05, 0.1), reduction (@700 °C)-reoxidation results in the exsolution of a Co_mFe_nNi_3-m-nO₄ spinel phase on the perovskite scaffold surface, while reduction (@750 °C)-reoxidation leads to the formation of both Co_mFe_nNi_3-m-nO₄ spinel phase and NiO nanoparticles. The exsolution of these highly active species increases the quantity of oxygen reduction active sites and effectively suppresses Sr segregation. The simultaneous formation of Co_mFe_nNi_3-m-nO₄ spinel phase and NiO nanoparticles induces B-site ion vacancies in the main phase, therefore facilitates the formation of oxygen vacancies. Additionally, the presence of Co_mFe_nNi_3-m-nO₄/NiO/PSCFN heterointerfaces promotes oxygen adsorption and transfer. The strong interactions among Co_mFe_nNi_3-m-nO₄, NiO, and PSCFN significantly enhance the structural stability. At 800 °C, Reo2-PSCFN0.1 achieves an output performance of 1.12 W cm⁻², representing a 36.6 % enhancement compared to PSCFN0.1. Moreover, the Rp of Reo2-PSCFN0.1 is merely 0.0186 Ω cm², marking a 40.4 % decrease relative to PSCFN0.1. This temperature-driven reduction-reoxidation strategy shows great promise as a novel approach for creating high-performance IT-SOFC cathodes.

阴极的高氧还原反应（ORR）催化活性和抗二氧化碳性能是固体氧化物燃料电池（SOFC）商业化应用的基础。因此，我们开发了一种温度驱动的还原-氧化策略，通过控制还原温度，在原位构建装饰有不同纳米粒子的异质结构包晶阴极。对于(Pr0.4Sr0.6)0.95Co0.2Fe0.8-xNixO3-δ（PSCFN，x = 0.05，0.1），还原（@700 ℃）-氧化反应导致包晶支架表面ComFenNi3-m-nO4尖晶石相的溶解，而还原（@750 ℃）-氧化反应则导致ComFenNi3-m-nO4尖晶石相和NiO纳米颗粒的形成。这些高活性物种的溶出增加了氧还原活性位点的数量，并有效抑制了硒偏析。ComFenNi3-m-nO4 尖晶石相和 NiO 纳米粒子的同时形成诱导了主相中的 B 位离子空位，从而促进了氧空位的形成。此外，ComFenNi3-m-nO4/NiO/PSCFN 异质界面的存在促进了氧的吸附和转移。ComFenNi3-m-nO4、NiO 和 PSCFN 之间的强相互作用显著提高了结构的稳定性。在 800 °C 时，Reo2-PSCFN0.1 的输出性能达到 1.12 W cm-2，与 PSCFN0.1 相比提高了 36.6%。此外，Reo2-PSCFN0.1 的 Rp 仅为 0.0186 Ω cm2，比 PSCFN0.1 降低了 40.4%。这种温度驱动的还原-氧化策略作为一种新型方法，在制造高性能 IT-SOFC 阴极方面显示出巨大的前景。

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引用次数: 0

Modeling and measurements of creep deformation in a ceramic fiber reinforced metal matrix composite 陶瓷纤维增强金属基复合材料蠕变变形的建模与测量

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-28 DOI: 10.1016/j.compositesb.2024.111926

Xu Kong, Yumin Wang, Qing Yang, Rui Yang

This study proposes a novel analytical model for creep deformation in long brittle fiber-reinforced metal matrix composites. Unlike traditional creep models based on the steady-state creep expression of the creep behavior for the matrix in the composite, this model addresses the unsteady-state creep behavior. It also highlights the similarity between the governing equations for creep testing of the composite and stress relaxation testing of the unreinforced matrix. Owing to load transfer from the creeping matrix to the rigid fiber during the creep process, the matrix experiences decreasing stress and theoretically never reaches a steady state. Creep tests are conducted on a SiC fiber-reinforced Ti–6Al–2Sn–4Zr–2Mo-0.1Si alloy composite, within a stress range of 1100∼1350 MPa at 500 °C, with strain variation measured by an extensometer. Experimental results reveal significant discrepancies between the observed data and predictions based on steady-state creep assumptions. The differences between previous models and the proposed model are discussed using the experimental data.

本研究提出了长脆纤维增强金属基复合材料蠕变变形的新型分析模型。与基于复合材料中基体蠕变行为的稳态蠕变表达式的传统蠕变模型不同，该模型针对的是非稳态蠕变行为。它还强调了复合材料蠕变测试与未增强基体应力松弛测试的控制方程之间的相似性。由于蠕变过程中载荷从蠕变基体传递到刚性纤维，基体的应力不断减小，理论上永远不会达到稳定状态。我们在碳化硅纤维增强的 Ti-6Al-2Sn-4Zr-2Mo-0.1Si 合金复合材料上进行了蠕变试验，应力范围为 1100∼1350 兆帕，温度为 500 °C，应变变化由拉伸计测量。实验结果表明，观察到的数据与基于稳态蠕变假设的预测之间存在显著差异。利用实验数据讨论了以前的模型与所提出的模型之间的差异。

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引用次数: 0

Effect of admixed silicone emulsion on water and chloride transport properties of concrete 掺入有机硅乳液对混凝土水和氯离子迁移性能的影响

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-26 DOI: 10.1016/j.compositesb.2024.111916

Fengjiang Li , Yu Fu , Jiangwei Zhu , Yuchen Wu , Jie Hu , Haoliang Huang , Fanghua Lei , Jiangxiong Wei , Qijun Yu

The addition of silicone is effective method for improving both surface and internal hydrophobicity of concrete, thus clarifying its effect on transport property of concrete is very important. In this study, both water and chloride transport properties of concrete incorporated with three silicone emulsions based on different active ingredients (silane oligomers or silane monomers) were evaluated and investigated. The results show that all three silicone emulsions exhibit no obvious negative effect on hydration and microstructure of cement paste; however, the admixed silicone emulsions increase both the thickness and porosity of ITZ in concrete. Therefore, the admixed silicone emulsions result in reduced compressive strength of concrete. Further, the incorporated silicone emulsions efficiently increase surface and internal water contact angle of concrete, thus mitigating both water absorption and chloride transport in concrete. Due to more pronounced interaction between silane oligomers and hydration products based on molecular dynamics simulation, the beneficial effect on improving hydrophobicity of concrete and halting water and chloride transport is more significant for the admixed silicone emulsion with silane oligomers as active ingredient.

添加有机硅是改善混凝土表面和内部憎水性的有效方法，因此明确有机硅对混凝土迁移特性的影响非常重要。在这项研究中，对掺入了基于不同活性成分（硅烷低聚物或硅烷单体）的三种有机硅乳液的混凝土的水和氯离子迁移性能进行了评估和研究。结果表明，三种有机硅乳液对水泥浆的水化和微观结构都没有明显的负面影响；但是，掺入的有机硅乳液会增加混凝土中 ITZ 的厚度和孔隙率。因此，掺入的有机硅乳液会降低混凝土的抗压强度。此外，掺入的有机硅乳液还能有效增加混凝土的表面和内部水接触角，从而减轻混凝土的吸水性和氯离子迁移。根据分子动力学模拟，硅烷低聚物与水化产物之间的相互作用更为明显，因此以硅烷低聚物为活性成分的掺入型有机硅乳液在改善混凝土憎水性、阻止水和氯离子迁移方面的效果更为显著。

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引用次数: 0

A novel mechanism to accelerate stress relaxation of toughened blends: Stress-induced core-shell morphological reconstruction and its application in thermoforming and dimensional stabilization 加速增韧共混物应力松弛的新机制：应力诱导的核壳形态重构及其在热成型和尺寸稳定中的应用

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-26 DOI: 10.1016/j.compositesb.2024.111910

Jielong Lin , Shibing Ye , Yong Zhang , Xiaoyun Yang , Jiqing Liu , Long Chen , Hongyao Xu

Improving thermoforming efficiency and dimensional stability in thermoplastic products is a common challenge. This study investigates toughened polyamide 612 (PA612) blends made by adding maleic anhydride-functionalized SEBS (mSEBS) elastomers, along with high-density polyethylene (HDPE), polyphenylene Oxide (PPO), and polyphenylene Sulfide (PPS). Analyses showed that mSEBS forms a core-shell structure with HDPE or PPO and a sea-island structure with PPS in the PA612 matrix. The study uniquely examines how these structures affect stress relaxation. The results, modeled by a steady-state creep model, revealed that the core-shell structures reduced the characteristic relaxation time (λ) by over three orders of magnitude compared to PA612/mSEBS blends. Additionally, PA612/mSEBS/HDPE blends were more temperature-sensitive, reducing λ by six orders of magnitude compared to PA612/mSEBS/PPO blends. Further analysis showed that stress-induced core-shell morphological reconstruction (SCMR) significantly improved stress relaxation by promoting extensive plastic deformation and energy dissipation. These toughened PA612 blends exhibited excellent thermoforming efficiency and dimensional stability. A 3D finite element model confirmed SCMR as an effective strategy for stress relaxation, providing valuable insights for designing toughened blends with superior processing efficiency and stability.

提高热塑性产品的热成型效率和尺寸稳定性是一项共同的挑战。本研究调查了通过添加马来酸酐功能化 SEBS（mSEBS）弹性体以及高密度聚乙烯（HDPE）、聚苯氧化物（PPO）和聚苯硫醚（PPS）制成的增韧聚酰胺 612（PA612）混合物。分析表明，mSEBS 与 HDPE 或 PPO 形成核壳结构，与 PA612 基质中的 PPS 形成海岛结构。该研究独特地考察了这些结构如何影响应力松弛。通过稳态蠕变模型模拟的结果显示，与 PA612/mSEBS 混合物相比，核壳结构将特征松弛时间 (λ)缩短了三个数量级以上。此外，PA612/mSEBS/HDPE 共混物对温度更敏感，与 PA612/mSEBS/PPO 共混物相比，λ 降低了六个数量级。进一步的分析表明，应力诱导的核壳形态重构（SCMR）通过促进广泛的塑性变形和能量耗散，显著改善了应力松弛。这些增韧的 PA612 共混物具有出色的热成型效率和尺寸稳定性。三维有限元模型证实了 SCMR 是一种有效的应力松弛策略，为设计具有卓越加工效率和稳定性的增韧共混物提供了宝贵的见解。

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引用次数: 0

Multifunctional highly conductive cellulose nanopaper with ordered PEDOT:PSS alignment enabled by external surface area-promoted phase separation 通过外表面积促进相分离实现具有有序 PEDOT:PSS 排列的多功能高导电性纤维素纳米纸

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering

Pub Date : 2024-10-25 DOI: 10.1016/j.compositesb.2024.111919

Ningxin Chen, Sida Xie, Jie Deng, Biao Wang, Shanchen Yang, Zhaohui Wang

Integrating cellulose, the most abundant biopolymer on Earth, with PEDOT:PSS, the most commercially available conducting polymer, can create multifunctional conductive nanopapers for sustainable electronics. However, conventional PEDOT:PSS/cellulose composites often exhibit limited conductivity, primarily due to the random distribution of PEDOT and the aggregation of PSS within the cellulose matrix. Herein, we introduce a confined phase separation approach that leverages the inherent physical characteristics of the cellulose substrate to enhance the performance of these composites. By systematically investigating the influence of the external surface area of nanocellulose on PEDOT:PSS coverage and composition evolution, we demonstrate that a higher external surface area ensures uniform PEDOT:PSS coating on nanocellulose networks and facilitates effective PSS removal during secondary doping. This process enhances phase separation and promotes ordered alignment of PEDOT chains along nanocellulose, resulting in an electrical conductivity of up to 252 S cm⁻¹. Such highly conductive nanopapers exhibit exceptional performances in supercapacitors and electromagnetic shielding, achieving an ultrahigh specific electromagnetic shielding effectiveness of 33,122 dB cm² g⁻¹ at only 6 μm thickness. Our study highlights the critical role of cellulose substrate selection at the nanoscale and elucidates the interactions within conducting polymers, offering a promising pathway for developing high-performance, sustainable electronics.

纤维素是地球上最丰富的生物聚合物，而 PEDOT:PSS 则是市场上最畅销的导电聚合物。将纤维素与 PEDOT:PSS 相结合，可为可持续电子产品制造出多功能导电纳米纸。然而，传统的 PEDOT:PSS/ 纤维素复合材料往往表现出有限的导电性，这主要是由于 PEDOT 的随机分布和 PSS 在纤维素基质中的聚集。在此，我们介绍一种密闭相分离方法，利用纤维素基质固有的物理特性来提高这些复合材料的性能。通过系统研究纳米纤维素的外表面积对 PEDOT:PSS 覆盖率和成分演变的影响，我们证明了较高的外表面积可确保 PEDOT:PSS 在纳米纤维素网络上的均匀涂覆，并有助于在二次掺杂过程中有效去除 PSS。这一过程加强了相分离，促进了 PEDOT 链沿纳米纤维素有序排列，从而使导电率高达 252 S cm-1。这种高导电性纳米纸在超级电容器和电磁屏蔽方面表现出卓越的性能，仅 6 μm 厚度就能达到 33,122 dB cm2 g-1 的超高比电磁屏蔽效能。我们的研究强调了纤维素基底选择在纳米尺度上的关键作用，并阐明了导电聚合物内部的相互作用，为开发高性能、可持续的电子产品提供了一条前景广阔的途径。

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引用次数: 0