【新文速递】2024年2月21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 1 篇，Composites Part B: Engineering 7 篇，Composites Science and Technology 1 篇

Composite Structures

Enhanced core rigidity classifier method (RJS 2.0): a comprehensive approach to properly measure elastic properties of sandwich structures

Rodrigo José da Silva, Júlio Cesar dos Santos, Túlio Hallak Panzera, Fabrizio Scarpa

doi:10.1016/j.compstruct.2024.117981

 

增强型芯材刚度分类法（RJS 2.0）：正确测量夹层结构弹性特性的综合方法

The primary RJS Method consists of a suggestive criterion for the qualitative and quantitative classification of the core rigidity relevance in sandwich panels based on the structure's ability to achieve pure bending behaviour. It also includes a set of assumptions that address the influence of the dimensions of the specimen on the elastic properties measured by three-point bending tests. The method allows for characterising the flexural modulus of sandwich panels through a homogenisation concept and comparing theoretical and experimental values to assess the amount of shear deformations occurring. Some limitations of the method were reported, such as the restriction to three-point bending tests and symmetrical sandwich structures (those composed of faces of the same thickness and composition). Additionally, the possible contribution of the rigidity of the face-to-core adhesives was not addressed when estimating the overall rigidity of a sandwich panel. Moreover, a direct link between the qualitative and quantitative classifications of core rigidity relevance was not achieved. In this new enhancement approach, called the RJS Method 2.0, not only are faces of different thicknesses and compositions addressed, but also the mechanical contribution of the face-to-core bonding when adhesives with relative thickness and rigidity are used. The new equations also cover four-point bending tests and clarify a direct association between the qualitative and quantitative classifications of core rigidity relevance. To facilitate the theoretical calculation of all equations, a MATLAB script is proposed. The outputs of the script are thoroughly compared to numerical results and data available in the literature, demonstrating the proper accuracy of the RJS Method 2.0 in predicting the elastic properties of sandwich structures under bending. Keywords: Sandwich structures; Core rigidity relevance; Test specimen dimensions; Flexural modulus; Core shear modulus; RJS Method.

主要的 RJS 方法包括一个建议性标准，用于根据结构实现纯弯曲行为的能力，对夹芯板的核心刚度相关性进行定性和定量分类。它还包括一套假设，用于解决试样尺寸对三点弯曲测试所测弹性特性的影响。该方法可通过均质化概念确定夹芯板的弯曲模量，并比较理论值和实验值，以评估发生的剪切变形量。报告指出了该方法的一些局限性，例如仅限于三点弯曲试验和对称夹层结构（由相同厚度和成分的面组成）。此外，在估算夹芯板的整体刚度时，没有考虑到面芯粘合剂的刚度可能造成的影响。此外，夹芯刚度相关性的定性和定量分类之间也没有建立直接联系。在这种被称为 RJS 方法 2.0 的新改进方法中，不仅涉及到不同厚度和成分的面，而且还涉及到在使用具有相对厚度和刚度的粘合剂时，面-芯粘合的机械贡献。新公式还涵盖了四点弯曲测试，并明确了夹芯刚性相关性的定性和定量分类之间的直接联系。为便于对所有方程进行理论计算，提出了一个 MATLAB 脚本。该脚本的输出结果与数值结果和文献中的数据进行了全面比较，证明了 RJS 方法 2.0 在预测夹层结构在弯曲条件下的弹性特性方面具有适当的准确性。关键词夹层结构；夹芯刚度相关性；试样尺寸；弯曲模量；夹芯剪切模量；RJS 方法。

Composites Part A: Applied Science and Manufacturing

Strength and toughness of bioderived resin based on hyperbranched crosslinking and its application to cellulose long Filament-Reinforced polymer composite

Dickens O. Agumba, Duc H. Pham, Giseok Park, Bijender Kumar, Jaehwan Kim

doi:10.1016/j.compositesa.2024.108098

基于超支化交联的生物源树脂的强度和韧性及其在纤维素长丝增强聚合物复合材料中的应用

A long-standing challenge in advanced material design is to transcend the conflict in strength and toughness since they are typically mutually exclusive. In this contribution, we overcome the conflict between the strength and toughness of a bioderived resin by a rational design using a hyperbranched carboxylic oligomer. The hyperbranched crosslinker established a platform for the conjugation of functional moieties and further tailored the mechanical properties of the resin. The obtained resin transcends the constraints of limited mechanical properties, attaining a spectacular increase in tensile strength (>240 %) and toughness (>837.1 %). Further, the adhesion strength (27.21 MPa) of the optimized resin to cellulose unveiled its suitability for natural fiber-reinforced composite fabrication. As proof of concept, the resin was integrated into plain weave cellulose long filament mats to fabricate an advanced biocomposite. The biocomposite displayed excellent flexural strength (353.86 ± 26.60 MPa) and stiffness (37.27 ± 2.58 GPa), disclosing its suitability in advanced lightweight structural applications.

先进材料设计中的一个长期挑战是如何克服强度和韧性之间的矛盾，因为这两者通常是相互排斥的。在这篇论文中，我们通过使用超支化羧酸低聚物进行合理设计，克服了生物源树脂的强度和韧性之间的矛盾。超支化交联剂为功能分子的共轭建立了一个平台，并进一步调整了树脂的机械性能。所获得的树脂突破了有限机械性能的限制，拉伸强度（>240%）和韧性（>837.1%）显著提高。此外，优化后的树脂与纤维素的粘附强度（27.21 兆帕）揭示了其在天然纤维增强复合材料制造中的适用性。作为概念验证，该树脂与平织纤维素长丝毡结合，制成了一种先进的生物复合材料。该生物复合材料显示出优异的抗弯强度（353.86 ± 26.60 兆帕）和刚度（37.27 ± 2.58 千兆帕），表明其适用于先进的轻质结构应用。

Composites Part B: Engineering

Failure of 3D-printed composite continuous carbon fiber hexagonal frames

Barakat-Ullah Bokharaie, Ramin Aghababaei, Marcelo A. Dias, Michal K. Budzik

doi:10.1016/j.compositesb.2024.111307

 

3D 打印复合材料连续碳纤维六边形框架的失效

This study presents an approach to enhancing and expanding the structural performance of composite materials by tailoring their geometry. We explored the potential of continuous carbon fiber composite additive printing to create complaint frames based on hexagonal cell design with the aim to better understand and control their mechanical performance. Our investigation examines the failure behaviour of these frames under remote tensile loading. By experimenting with various geometries and aspect ratios at the frame sites, we gained insight into different failure loads and modes. To predict these results, we developed a computational model based on multiscale homogenisation and the Hashin damage criterion, which showed a high degree of precision compared to our experimental results. The findings validate the effectiveness of our computational model, but also highlight the practical applications of additive manufacturing of composites. This research aims to contribute to the advancement of structural design and material optimization by engineering of composite materials for specific applications, emphasizing the integration of their intrinsic strength and lightweight properties with material efficiency and compliance achieved through geometric design considerations.

本研究提出了一种通过调整复合材料的几何形状来增强和扩展其结构性能的方法。我们探索了连续碳纤维复合材料添加剂打印的潜力，以创建基于六边形单元设计的投诉框架，目的是更好地了解和控制其机械性能。我们的研究考察了这些框架在远程拉伸负载下的失效行为。通过实验框架部位的各种几何形状和长宽比，我们深入了解了不同的失效载荷和模式。为了预测这些结果，我们开发了一个基于多尺度均质化和 Hashin 损伤准则的计算模型，与实验结果相比，该模型显示出很高的精度。研究结果验证了我们计算模型的有效性，同时也凸显了复合材料增材制造的实际应用。这项研究旨在通过针对特定应用的复合材料工程设计，促进结构设计和材料优化的发展，强调将复合材料的内在强度和轻质特性与通过几何设计考虑实现的材料效率和顺应性相结合。

Directionally induced high-density secondary interaction for enhancing the bonding reliability of titanium alloy and CFRTP via functional Schiff base-contained polymer

Jianhui Su, Xinbo Wang, Caiwang Tan, Swee Leong Sing, Shengming Liang, Xueyan Zhang, Yixuan Zhao, Bo Chen, Xiaoguo Song

doi:10.1016/j.compositesb.2024.111316

通过含功能性希夫碱聚合物定向诱导高密度二次相互作用，提高钛合金和 CFRTP 的粘接可靠性

For lightweight applications, the interfacial bonding reliability determines the service life of Ti–6Al–4V titanium alloy (TC4)/carbon fiber reinforced thermoplastic (CFRTP) joints. Traditional joining methods limit their applications. In this study, a functional Schiff base-contained polymer was successfully synthesized to modify the TC4 surface. The results indicated the directionally induced high-density complexation between the synthesized Schiff base and the titanium atom from the TC4 sheet and the secondary interaction between the synthesized Schiff base-contained polymer and CFRTP matrix occurred, which improved the bonding reliability of the TC4/CFRTP joint. The combination of the high-density secondary interaction and synergistic effect between the functional groups enhanced the interfacial bonding strength by 287 % to 38.73 MPa. This was remarkably higher than the bonding strength improved by 46 % to 14.64 MPa via the introduction of micromolecule Schiff base that consists of same functional groups. The significant enhancement of the interfacial bonding reliability was thus achieved. These results were beneficial to future research to improve the reliability of metal-CFRTP hybrid joints.

对于轻型应用而言，界面粘接的可靠性决定了 Ti-6Al-4V 钛合金 (TC4)/ 碳纤维增强热塑性塑料 (CFRTP) 接头的使用寿命。传统的连接方法限制了它们的应用。在本研究中，成功合成了一种含有希夫碱的功能性聚合物来修饰 TC4 表面。结果表明，合成的希夫碱与 TC4 片材中的钛原子之间发生了定向诱导的高密度络合，合成的含希夫碱聚合物与 CFRTP 基体之间发生了二次作用，从而提高了 TC4/CFRTP 接头的粘接可靠性。高密度二次作用和官能团之间的协同效应使界面粘接强度提高了 287%，达到 38.73 兆帕。这比通过引入由相同官能团组成的微分子席夫碱提高的粘接强度高出 46% 至 14.64 兆帕。因此，界面键合的可靠性得到了显著提高。这些结果有利于今后提高金属-CFRTP 混合接头可靠性的研究。

Mechanical performance and radar-absorption capacity of carbon Material–Reinforced polymethacrylimide foam: Preparation, comparison, and design

Shijun Song, Chao Xiong, Junhui Yin, Zhaoshu Yang, Aijun Gao, Fang Zhao, Yang Cao, Chao Han, Junjie Xie, Bo Tang, Lei Liu

doi:10.1016/j.compositesb.2024.111317

碳材料增强聚甲基丙烯酰亚胺泡沫的机械性能和雷达吸收能力：制备、比较和设计

Herein, radar-absorbing polymethacrylimide (RAPMI) foam was prepared using the particle foaming method. Nineteen samples were prepared based on different ratios and absorbent types, and their microstructural characteristics were analyzed and compared. Their dielectric constant and loss tangent were measured at 2–18 GHz, and the electromagnetic (EM) characteristics were analyzed. Subsequently, their mechanical properties were tested. The effect mechanism of the absorbents on the EM and mechanical behavior was analyzed, and the experimental data were compared. Finally, a laminated foam was designed. Results show that the samples can achieve 90% bandwidth effective absorption (reflection loss ≤ −10 dB) at 33.6-mm thickness and 18.6%, 32.4%, 62.5%, 62.9%, 35.7%, and 51.9% maximum increases in compressive strength, compressive modulus, tensile strength, tensile modulus, shear strength, and shear modulus, respectively, compared with particle polymethacrylimide (PMI) foam. The designed laminated foam can theoretically achieve full-band effective absorption at a minimum thickness of 15.3 mm. The preparation of RAPMI foam is simple and inexpensive, and this research strengthens the engineering application of PMI foam in cutting-edge fields, such as military and aerospace. It provides an important reference for researchers, technicians, and engineers in the fields of absorbing materials, polymers, and composites.

本文采用粒子发泡法制备了雷达吸收聚甲基丙烯酰亚胺（RAPMI）泡沫。根据不同的比例和吸收剂类型制备了 19 个样品，并对其微观结构特征进行了分析和比较。在 2-18 GHz 频率下测量了它们的介电常数和损耗正切，并分析了电磁（EM）特性。随后，测试了它们的机械性能。分析了吸收剂对电磁和机械行为的影响机制，并对实验数据进行了比较。最后，设计了一种层压泡沫。结果表明，与颗粒聚甲基丙烯酰亚胺（PMI）泡沫相比，样品在 33.6 毫米厚度时可实现 90% 的带宽有效吸收（反射损耗≤ -10dB），抗压强度、抗压模量、拉伸强度、拉伸模量、剪切强度和剪切模量的最大增幅分别为 18.6%、32.4%、62.5%、62.9%、35.7% 和 51.9%。所设计的层压泡沫理论上可在最小厚度为 15.3 毫米时实现全波段有效吸收。RAPMI 泡沫的制备方法简单、成本低廉，这项研究加强了 PMI 泡沫在军事和航空航天等前沿领域的工程应用。它为吸波材料、聚合物和复合材料领域的研究人员、技术人员和工程师提供了重要参考。

Experimental and numerical study of thermoforming-induced deformation in glass fiber/polyetherimide thermoplastic wing leading edge

Hongzhou Zhai, Qi Wu, Yuxi Zhang, Ke Xiong

doi:10.1016/j.compositesb.2024.111319

玻璃纤维/聚醚酰亚胺热塑性机翼前缘热成型诱导变形的实验和数值研究

Thermoplastic composites with complex structures are more difficult to manufacture than simple thermoset composite laminates. In this study, two composite wing leading edges (CWLEs) made from glass fiber/polyetherimide were thermoformed using a four-step manufacturing method, resulting in two CWLEs with an average 1.36% porosity and 0.155 mm maximum spring-back. Finite element thermo–mechanical coupling analysis was conducted to elucidate the deformation mechanism of the composite wing leading edge. When the tool-part interfacial layer was considered, the abscissa of the CWLE end is 17.93 mm that was close to the experimental value of 17.83 mm. By comparing the models with and without the interfacial layer, the results suggested that barely any temperature gradient existed with no impact on the residual deformation, and the thin interfacial layer did not affect temperature but decreased in-plane strain transfer from mold to composite, influencing bending stress and mitigating composite deformation.

结构复杂的热塑性复合材料比简单的热固性复合材料层压板更难制造。在这项研究中，采用四步制造法对玻璃纤维/聚醚酰亚胺制成的两个复合材料机翼前缘（CWLE）进行了热成型，得到了平均孔隙率为 1.36%、最大回弹率为 0.155 mm 的两个 CWLE。为了阐明复合材料机翼前缘的变形机制，对其进行了有限元热机械耦合分析。当考虑到工具部分界面层时，CWLE 端部的离散值为 17.93 毫米，与实验值 17.83 毫米接近。通过比较有无 界面层的模型，结果表明几乎不存在温度梯度，对残余变形没有影响，薄界面层不影响温度，但减少了从模具到复合材料的面内应变传递，影响了弯曲应力，减轻了复合材料变形。

Fiber dispersion as a quality assessment metric for pultruded thermoplastic composites

Nicholas Elderfield, Oliver Cook, Joanna C.H. Wong

doi:10.1016/j.compositesb.2024.111321

作为拉挤热塑性复合材料质量评估指标的纤维分散性

Fiber-reinforced polymer composites are often assessed by measuring void content via thresholding of optical microscope cross-section images, relying on contrast between voids and surrounding material to differentiate them. This is effective when dealing with materials with primarily closed voids, a characteristic common to thermoset matrix composites. However, composites that exhibit fiber impregnation issues, often due to high matrix viscosity as in thermoplastic composites, will typically contain open pores which the mounting resin used to embed the sample for grinding and polishing operations can infiltrate. Voids filled with this resin can be difficult to distinguish from the matrix, leading to inaccurate void content measurements. To circumvent this, a strategy for assessing impregnation quality based on fiber dispersion is proposed. During impregnation processes, the fiber network exhibits a tendency to become locally compacted by flow fronts, leading to low permeability fiber clusters that are less likely to become fully impregnated. Fiber dispersion quantifies the percentage of non-clustered fibers from position data and provides information on degree of impregnation and interfiber void locations. The effects of processing speed and temperature on fiber dispersion are investigated in the production of continuous carbon fiber-reinforced polyetherimide (PEI) additive manufacturing feedstock material from commingled yarn using multi-die pultrusion. Fiber dispersion is observed to increase with slower pultrusion speeds, correlating with higher flexural strength and stiffness properties. This increase in fiber dispersion with longer die residency time indicates that the decompaction of fiber clusters is highly time-dependent and occurs by dispersal of fibers away from cluster boundaries.

纤维增强聚合物复合材料的评估通常是通过光学显微镜截面图像的阈值来测量空隙含量，依靠空隙与周围材料的对比度来区分空隙。这种方法在处理以封闭空隙为主的材料时非常有效，而封闭空隙是热固性基复合材料的常见特征。然而，通常由于热塑性复合材料基体粘度高而导致纤维浸渍问题的复合材料通常会含有开放的孔隙，用于嵌入样品进行研磨和抛光操作的镶嵌树脂会渗入这些孔隙。这种树脂填充的空隙很难与基体区分开来，从而导致空隙含量测量不准确。为了避免这种情况，我们提出了一种基于纤维分散性的浸渍质量评估策略。在浸渍过程中，纤维网络会因流动前沿而呈现局部压实的趋势，从而形成低渗透性的纤维簇，这些纤维簇不太可能完全浸渍。纤维分散度可从位置数据中量化非成团纤维的百分比，并提供浸渍程度和纤维间空隙位置的信息。在使用多模拉挤工艺从混合纱线生产连续碳纤维增强聚醚酰亚胺（PEI）添加剂制造原料材料的过程中，研究了加工速度和温度对纤维分散的影响。观察到纤维分散度随着拉挤速度的减慢而增加，这与较高的抗弯强度和刚度特性相关。这种纤维分散性随模具停留时间延长而增加的现象表明，纤维簇的分解与时间高度相关，并且是通过纤维远离簇边界而分散的。

Validation of shape change predictions for stamp forming of carbon fiber thermoplastic composite laminates

Eduardo Barocio, Justin Hicks, Garam Kim, Anthony Favaloro, Gourab Ghosh, Johnathan Goodsell, R. Byron Pipes

doi:10.1016/j.compositesb.2024.111325

验证碳纤维热塑性复合材料层压板冲压成型的形状变化预测值

Stamp forming with thermoplastic composites provides high-rate production of structural components. A series of physical phenomena develops concurrently as a blank of fiber reinforced thermoplastic is consolidated, reheated, stamp formed, and cooled within the tool, and released from the tool in the stamp forming process. Transient phenomena contributing to the residual deformation of continuous fiber-reinforced thermoplastics processed by stamp forming were described and characterized in this work. The transient phenomena considered included anisotropic heat transfer, anisotropic shrinkage, thermoviscoelastic behavior, and semi-crystalline polymer melting and crystallization kinetics. A comprehensive experimental characterization of the material properties required to model the phenomena involved in shape change is summarized in this work. The digital twin of this process, termed FORM3D and based on the finite element solvers ABAQUS and ANIFORM, has been constructed with the goal of describing the important phenomena in thermoplastic stamp forming, particularly to predict shape change. Shape change predictions made with FORM3D were validated against experimental measurements for a double curvature geometry made with a quasi-isotropic stacking sequence. The double curvature geometry developed both spring-in and spring-out deformations in the minor and major radii of curvature, respectively. FORM3D predictions were in excellent agreement with the experiments in both magnitude and distribution of the deformation. The same correlation was observed for three repetitions of the stamp formed experiment carried out in this work.

使用热塑性复合材料进行冲压成型可实现结构部件的高速生产。在冲压成形过程中，纤维增强热塑性塑料坯料在工具内固结、加热、冲压成形和冷却，并从工具中释放出来，一系列物理现象同时发生。在这项工作中，描述并描述了导致通过冲压成型加工的连续纤维增强热塑性塑料残余变形的瞬态现象。考虑的瞬态现象包括各向异性传热、各向异性收缩、热变形弹性行为以及半结晶聚合物熔化和结晶动力学。这项工作总结了建立形状变化现象模型所需的材料特性的综合实验特征。以有限元求解器 ABAQUS 和 ANIFORM 为基础，构建了这一过程的数字孪生模型 FORM3D，旨在描述热塑性冲压成形中的重要现象，特别是预测形状变化。使用 FORM3D 进行的形状变化预测与使用准各向同性堆叠序列制作的双曲率几何体的实验测量结果进行了验证。双曲率几何体在小曲率半径和大曲率半径上分别产生了弹入和弹出变形。FORM3D 的预测结果与实验结果在变形的大小和分布方面都非常吻合。在这项工作中进行的冲压成形实验的三次重复中也观察到了相同的相关性。

Nanostructure and damage characterisation of bitumen under a low cycle strain-controlled fatigue load based on molecular simulations and rheological measurements

Yangming Gao, Xueyan Liu, Shisong Ren, Eli I. Assaf, Pengfei Liu, Yuqing Zhang

doi:10.1016/j.compositesb.2024.111326

基于分子模拟和流变测量的低循环应变控制疲劳载荷下沥青的纳米结构和损伤表征

Bitumen fatigue resistance is critical to determine the overall fatigue performance and service life of asphalt pavements. However, the mechanisms responsible for fatigue damage of bitumen have previously not been well understood. Molecular dynamics (MD) simulation has recently emerged as a powerful computer-aided numerical technique to model the microscopic failure behaviours in materials. This study aims to use the MD method to investigate the molecular origin of bitumen fatigue damage. The molecular models of the virgin and aged PEN70/100 bitumen were firstly constructed based on their saturate, aromatic, resin and asphaltene (SARA) four fractions. An MD equilibrium was run on the developed bitumen models with the assigned interatomic potentials. Following an MD-based tensile simulation, a strain-controlled fatigue simulation was performed to study the nanostructure and damage behaviours of the virgin and aged bitumen under fatigue loading by calculating the stress-strain response, potential energy, molecular structure and nanovoid volumes. Furthermore, a rheometer measurement was also conducted to characterise the fatigue damage of the bitumen directly by a crack length at the macroscale. Results indicate that the bitumen molecules become unfolded and tend to align along the loading direction when fatigue loading was applied. The change in the molecular configuration helped the molecular chains move closer together and thus contributed to the reduction of the intermolecular interactions including the van der Waals and Coulombic energies. With the increasing load cycles, nanovoids were formed and grew in the bitumen through molecular rearrangement and movement, leading to microscopic fatigue damage of the bitumen. It was found that the aged bitumen produced more severe fatigue damage than the virgin bitumen, which was indicated by the MD-based nanovoid volume at the molecular scale and the DSR-based crack length at the macroscale. The findings from MD simulation provide a fundamental understanding of the molecular origin of fatigue damage, that cannot be experimentally detected for bitumen materials.

沥青的抗疲劳性对于决定沥青路面的整体疲劳性能和使用寿命至关重要。然而，以前人们对沥青疲劳破坏的机理并不十分了解。分子动力学（MD）模拟是最近兴起的一种强大的计算机辅助数值技术，可用于模拟材料的微观破坏行为。本研究旨在利用 MD 方法研究沥青疲劳破坏的分子起源。首先根据饱和沥青、芳香沥青、树脂沥青和沥青质沥青（SARA）四种组分构建了原生沥青和老化 PEN70/100 沥青的分子模型。在所建立的沥青模型上运行指定原子间势的 MD 平衡。在基于 MD 的拉伸模拟之后，进行了应变控制疲劳模拟，通过计算应力-应变响应、势能、分子结构和纳米体积，研究了原始沥青和老化沥青在疲劳加载下的纳米结构和损伤行为。此外，还进行了流变仪测量，通过宏观尺度上的裂缝长度直接表征沥青的疲劳损伤。结果表明，当施加疲劳载荷时，沥青分子会展开，并倾向于沿载荷方向排列。分子构型的变化有助于分子链靠拢，从而有助于减少分子间的相互作用，包括范德华能和库仑能。随着载荷循环次数的增加，沥青中的分子重新排列和移动形成并增长了纳米固体，导致沥青的微观疲劳损伤。研究发现，老化沥青比原生沥青产生了更严重的疲劳损伤，分子尺度上基于 MD 的纳米形体体积和宏观尺度上基于 DSR 的裂纹长度都表明了这一点。MD 模拟的研究结果从根本上揭示了疲劳损伤的分子起源，而对于沥青材料来说，这种损伤是无法通过实验检测到的。

Composites Science and Technology

Hydrophobic PI/SiO2 composites with excellent dielectric property and thermal stability via simple modification

Xiangyu Mei, Azim Abdullaev, Qingbiao Yang, Kun Peng, Shuaida Shi, Fujian Liu, Yinsong Si, Yaqin Fu

doi:10.1016/j.compscitech.2024.110508

 

通过简单改性获得具有优异介电性能和热稳定性的疏水性 PI/SiO2 复合材料

Polyimide (PI) has been extensively used in 5G microelectronics however the relatively high dielectric constant (∼3.5) and moisture adsorption have greatly limit its practical applications in high-frequency region. Here hydrophobic PI/SiO2 composite films with low dielectric constant and excellent thermal stability were synthesized by dispersing methyl modified hollow silica nanospheres (MHS) into polyamic acid solution prior to imidization treatment. Comparing with unmodified hollow silica nanospheres (HS), the MHS obtained through methyl modification can disperse uniformly in the PI matrix. Thus, the relaxation and orientation polarization of the PI chains as well as their electron migration are suppressed, resulting in a significant decrease in dielectric constant. The PI/MHS-10% film exhibits a stable low dielectric constant (1.9–2.3) in the high-frequency range (8.2 GHz–12.4 GHz), meanwhile maintains a high breakdown voltage (192 kV/mm), mechanical properties (64 MPa) and an excellent thermal stability (Td5% = 546.5 °C; Tmax = 589.0 °C). Moreover. PI/MHS demonstrates much lower linear expansion coefficient of 25.0 ppm/K that better matches the substrate. The surface contact angle of PI/MHS increases from 73° to 110° and the water absorption rate decreases from 3.1% to 1.6%, effectively avoiding the moisture adsorption. This work provides a simple method to prepare high-performance composite films for 5G practical applications.

聚酰亚胺（PI）已被广泛应用于 5G 微电子领域，但相对较高的介电常数（∼3.5）和吸湿性大大限制了其在高频区域的实际应用。本文通过将甲基改性空心二氧化硅纳米球（MHS）分散到聚酰胺酸溶液中，然后进行亚胺化处理，合成了具有低介电常数和优异热稳定性的疏水性 PI/SiO2 复合薄膜。与未改性的空心二氧化硅纳米球（HS）相比，通过甲基化改性得到的 MHS 能够均匀地分散在 PI 基体中。因此，PI 链的弛豫和取向极化及其电子迁移受到抑制，从而显著降低了介电常数。PI/MHS-10% 薄膜在高频范围（8.2 GHz-12.4 GHz）内表现出稳定的低介电常数（1.9-2.3），同时保持了较高的击穿电压（192 kV/mm）、机械性能（64 MPa）和出色的热稳定性（Td5% = 546.5 °C；Tmax = 589.0 °C）。此外。PI/MHS 的线膨胀系数更低，仅为 25.0 ppm/K，与基底更匹配。PI/MHS 的表面接触角从 73°增至 110°，吸水率从 3.1% 降至 1.6%，有效避免了水分吸附。这项工作为制备面向 5G 实际应用的高性能复合薄膜提供了一种简单的方法。