ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Lin-Xuan Fang,Yun-Gang Feng,Li Li,Guan-Wu Yin,Hualan Wang,Zheng Xu,Li-Wen Xu
Two silicon-containing eugenol-based benzocyclobutene monomers were prepared by a simple solvent-free hydrosilylation reaction. After heat treatment, a series of materials were obtained by a free radical addition reaction, [4 + 4] cycloaddition, or [4 + 2] Diels–Alder cycloaddition. All polymers displayed high thermostability with a 5% weight loss temperature (T5d) of over 410 °C and a glass transition temperature (Tg) of up to 216 °C as well as a good transmittance of 90% varying from 500 to 800 nm. In particular, all polymers also exhibited good hydrophobicity with contact angles exceeding 100° and water absorption as low as 8‰ after immersing in boiling water for 72 h. It should be noted that P3 showed excellent dielectric properties with a dielectric constant (Dk) of 2.48 and a dielectric loss (Df) of 6.38 × 10–3 at a high frequency of 2 GHz as well as good flame retardancy due to the high content of cyclotriphophazene compared with those of P1, P2, and previously reported biobased materials. The above advantages indicate that eugenol-based low-dielectric materials have great potential for application in encapsulation resins in the field of microelectronics.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 4
·857
·
IF 3.2
Tiange Xue,Xinqing Su,Shixiang Yu,Meng Meng,Xinya Xu,Jinqi Xin,Jinjin Ran
In this work, a small amount of AlN whiskers (ranging from 2 wt.% to 8 wt.%) was incorporated into CaO-MgO-ZnO-B2O3-SiO2(CMZBS)–glass/Al2O3composites so as to obtain glass-ceramics with a thermally conductive network through sintering between 700 °C and 1000 °C. Special attention was given to the densification behavior, dielectric properties, and thermal conductivity of CMZBS/Al2O3/AlN–glass–ceramic composites with varying AlN whisker contents. According to the results, composites with desirable thermal, mechanical, and dielectrical properties were successfully fabricated. Notably, the composites containing 6 wt.% AlN whiskers, sintered at 800 °C, exhibited the most optimal comprehensive properties (dielectric constant of 7.06, dielectric loss of 383 × 10−5, thermal expansion coefficient of 6.40·10−6/K, flexural strength of 180 MPa, and thermal conductivity of 5.17 W/(m·K)). Given these attributes, this CMZBS/Al2O3/AlN composite holds great potential for applications in LTCC (low-temperature co-fired ceramic).
研究领域:
材料科学
·
电子工程
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Miao Wang,Yijin He,Xiaoyu Yang,Xuhui Hou,Wenxuan Li,Shaobo Tan,Zhicheng Zhang
With the increasing demand for dielectric materials in high-frequency microwave applications, fluoropolymer-based dielectric materials have been widely utilized due to their excellent dielectric and insulation properties. However, the low thermal conductivity limits their ability to meet the thermal dissipation requirements during high-frequency and high-speed signal transmission. The present study introduces a pioneering interface engineering strategy wherein C–F bonds on the surface of ethylene-tetrafluoroethylene copolymer (ETFE) are photo-catalytically activated, enabling successful grafting of poly(glycidyl methacrylate) (PGMA) chain segments. Subsequently, the resulting graft copolymers are blended with thermally conductive h-BN filler to prepare composite dielectric materials. The results demonstrate that the incorporation of PGMA segments significantly enhances the interfacial compatibility between the ETFE matrix and h-BN filler, resulting in composites with a dense microstructure and outstanding dielectric and thermal properties. At a filler content of 30 vol%, the ETFE-g-PGMA@BN composite achieves an in-plane thermal conductivity of 4.2 W (m K)−1 and a through-plane thermal conductivity of 0.77 W (m K)−1. Moreover, at 1 GHz, the composite exhibits a dielectric constant of 2.2 and a dielectric loss of 0.004. This work presents a novel interface design strategy for surface modification of PTFE-based fluoropolymers, expanding their potential applications in printed circuit boards (PCBs) and providing a new direction for the design of polymer-based dielectric materials.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xianqiang Chen,Binfeng Zhao,Naichao Chen,Jin Cheng,Mingzhao Dang,Feng Wang,Xinwei Xu,Hong Wang
Low-temperature-fired microwave ceramics are key to realizing the integration and miniaturization of microwave devices. In this study, a facile wet chemical method was applied to synthesize homogenous nano-sized CaF 2 powders for simultaneously achieving low-temperature sintering and superior microwave dielectric properties . Pure CaF 2 ceramics sintered at 950 °C for 6 h with good microwave dielectric properties (ε r = 6.22, Q×f = 36,655 GHz, and τ f = −102 ppm/°C) was achieved. The microwave dielectric properties of the CaF 2 ceramics were further improved by introducing LiF as a sintering aid. The sintering temperature of CaF 2 -based ceramics was effectively lowered from 950 °C to 750 °C with 10 wt% LiF doping, and excellent microwave dielectric properties (ε r = 6.37, Q×f = 65,455 GHz, and τ f = −71 ppm/°C) were obtained.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yefeng Feng,Junquan Zhou,Peiyao Chen,Maolin Bo,Qihuang Deng
High permittivity and low dielectric loss play a crucial role in enabling the applications of polymer-based composite dielectrics bearing ceramic particles in promising energy storage devices. The well-designed synergy of the two types of ceramics with varying conduction ability can effectively balance the high permittivity and low dielectric loss in composites. In this study, we optimised the dielectric properties of novel poly (vinylidene fluoride) (PVDF)/Fe 2 TiO 5 (FTO)/graphite ternary composite films fabricated via solution casting technology. FTO pseudo-perovskite micro-particles with semiconducting features and rich ionic electric dipoles were used as the primary filler. Graphite micro-particles with high conductivity were used as an assistant filler. PVDF with rich ferroelectric domains was utilised as a polymeric matrix. High permittivity of the composites was attributed to both the mild PVDF/FTO and strong PVDF/graphite interface polarisation effects. Compared with PVDF/FTO binary composites, the ternary composites filled with low-content graphite exhibited significantly improved permittivity and slightly increased dielectric loss. Controllable low-level interface leakage conduction was responsible for the low conductivity and dielectric loss as well as the acceptable electric breakdown strength achieved in the ternary composites. The ternary composite bearing 20 wt% FTO and 0.1 wt% graphite showed a high permittivity of ~45 at 100 Hz, low dielectric loss of ~0.15 at 100 Hz, and high breakdown strength of ~225 MV m −1 . We believe that this study will assist in facilitating the development of novel composite dielectrics containing semiconducting A 2 BO 5 pseudo-perovskite ceramic fillers.
研究领域:
材料科学
·
能源存储
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Zilong Zhang,Shuai Wang,Yangyang Lv,Xiqiao Chen,Zhuang Wu,Yanhong Zou
In this work, MnO 2 -deposited graphene foams (MnO 2 /GFs) were synthesized using a simple hydrothermal method . By controlling the content of MnO 2 deposited on the surface of graphene skeleton, a series of MnO 2 /GFs composites are easily synthesized. Benefiting from the well-designed interconnected 3D porous network structure and strong interfacial polarization between MnO 2 nanoparticles and graphene skeleton, the MnO 2 /GFs composite displays excellent microwave absorbing properties. The optimized MnO 2 /GFs nanocomposite achieves the strongest electromagnetic absorption with a reflection loss (RL) of −53 dB and the qualified absorption bandwidth is up to 7.0 GHz. The results may provide some valuable design guidelines for lightweight, wide-band, and highly efficient electromagnetic wave absorption materials.
研究领域:
材料科学
·
电磁学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Huiru Wang,Jingyi Liu,Sorour Sadeghzade,Runsheng Hou,Hongyan Yuan
Among piezo composites, 0–3 type ceramic/polymer-based composites have balanced properties and flexible manufacturing processes, allowing them to tackle challenges in wearable electronics and sensing technology. However, due to a misfit between the dielectric coefficients of the ceramic particles and polymer matrix , poling 0–3 composites is difficult. Therefore, in this study, we develop a novel poling method that combines the merits of normal corona poling and oil-based poling methods to activate a lead zirconium titanate (PZT)/Polyethylene glycol diacrylate (PEGDA) composite. The influence of various parameters (voltage, temperature, poling duration, and time of ageing) on the piezoelectric and dielectric properties of the PZT/polymer composite were evaluated. For the 0–3 PZT/PEGDA composites (67 wt%), the optimal poling parameters were found to be 60 min poling duration, 25 °C, and 24 kV. The d 33 (32 pC/N) obtained by the proposed poling method is about 3 times that obtained by the normal corona poling method (11 pC/N). This modified poling method was shown to be more effective than the conventional method for a range of filler contents (50 wt%, 67 wt%, and 75 wt%). It was also found that the d 33 value of the PZT/PEGDA composite increased over time and was attributed to the increase of the composite dielectric constant after poling. Finally, sensing elements were assembled from the poled samples and evaluated, which shows the potential for detecting tiny signals in sensing and soft robotics.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
Crystals
·
2018
·Vol. 8
·期 3
·113
·
IF 2.144
Hui Wang,Qin Li,Chaoyue Wang,Huan He,Jianding Yu,Jiayue Xu
High-quality Ta-doped La2Ti2O7(Ta-LTO) single crystal of about 40 mm in length and 5 mm in diameter was successfully prepared by the optical floating zone method. An X-ray rocking curve reveals that the crystal of LTO has excellent crystalline quality. As-grown crystals were transparent after annealing in air and the transmittance is up to 76% in the visible and near-infrared region. X-ray diffraction showed that this compound possessed a monoclinic structure with P21space group. The dielectric properties were investigated as functions of temperature (0~300 °C) and frequency (102Hz~105Hz). Dielectric spectra indicated an increase in the room-temperature dielectric constant accompanied by a drop in the loss tangent as a result of the Ta doping. One relaxation was observed in the spectra of electric modulus, which was ascribed to be related to the oxygen vacancy. The dielectric relaxation with activation energy of 1.16 eV is found to be the polaron hopping caused by the oxygen vacancies.Keywords:Ta-LTO single crystal;floating zone method;dielectric properties;oxygen vacancy
研究领域:
材料科学
·
物理学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Y.J. Niu,M.T. Liu,M.F. Li,J.X. Bi,H.T. Wu
Wolframite-structured Zn 1-x Mg x ZrNb 2 O 8 (0 ≤ x ≤ 0.1) ceramics were synthesized by the conventional solid-state method. The effects of Mg 2+ substitution on the sinter ability, crystal structures and microwave dielectric properties were systematically investigated. The Q·f values increased from 46,800 GHz to 53,400 GHz when the x value increased from 0 to 0.1. Based on the complex chemical bond theory, the intrinsic parameters were calculated to analyze the mechanism of dielectric loss in Zn 0.9 Mg 0.1 ZrNb 2 O 8 . The total lattice energy and bond energy of the Zn 0.9 Mg 0.1 ZrNb 2 O 8 were higher than that of ZnZrNb 2 O 8 , which was corresponding with the decrease of dielectric loss in the wolframite-structured compounds. The dielectric constant ( ε r ) and temperature coefficient of resonant frequency ( τ f ) of Zn 1-x Mg x ZrNb 2 O 8 ceramics were also heavily influenced by the addition of Mg 2+ . Typically, the dense Zn 0.9 Mg 0.1 ZrNb 2 O 8 ceramics sintered at 1200 °C exhibited excellent microwave dielectric properties with ε r = 27.82, Q·f = 53,400 GHz and τ f = −45.82 ppm/°C.
研究领域:
材料科学
·
物理学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2013
·
IF 1.789
Qing Ma,Songping Wu,Yingxian Fan
Zn 2 SnO 4 ceramics were synthesized by the solid-state method. B 2 O 3 was added into the system to lower the sintering temperature . B 2 O 3 -doped Zn 2 SnO 4 materials were characterized by X-ray diffraction (XRD), electron microscopies (SEM/TEM/HRTEM/EDS), Raman and XPS spectroscopies. The inverse-spinel Zn 2 SnO 4 ceramics (containing 1 wt% B 2 O 3 ) sintered at 975 °C exhibited good microwave dielectric properties : ε r =9.3, Q × f =62,000 GHz and τ f =−50 ppm/°C. Zn 2 SnO 4 ceramics with low sintering temperatures are promising candidate materials for low-temperature cofired millimeter-wave devices.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Liang Shi,Xueying Wang,Rui Peng,Yongcheng Lu,Cheng Liu,Dainan Zhang,Huaiwu Zhang
A series of Mn 2+ -doped Mg 1-x Mn x Ta 2 O 6 (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ceramics were synthesized by solid-state reaction method. The influence of introducing Mn–O bonds as a partial replacement for Mg–O bonds on the lattice and microwave dielectric properties was systematically investigated. XRD and Rietveld refinement confirm that Mn 2+ occupies the 2a Wyckoff position and forms a pure trirutile phase. Moreover, based on the chemical bond theory, the dielectric constant is mainly affected by the ionicity of the Ta–O bond. The lattice and dielectric properties remain relatively stable with Mn 2+ doping below 0.1, but excessive Mn 2+ doping leads to pronounced distortion of the lattice, which is not beneficial for lattice stability and microwave dielectric properties. Introducing an appropriate amount of Mn–O bonds with high bond dissociation energy facilitates MgO6 octahedron stability, which improves the thermal stability of the lattice. Accordingly, the microwave dielectric properties for 0.06 Mn 2+ -doped MgTa 2 O 6 ceramics were determined: ε r = 28, Q × f = 105,000 GHz (at 7.5 GHz), τ f = 19.5 ppm/ ° C.
研究领域:
材料科学
·
无机化学
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产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2022
·
IF 6.959
Qinzhao Sun,Bofeng Shi,Tianran Zhang,Weijie Yang,Jiping Wang,Lixue Zhang,Dezhen Xue,Zepeng Wang,Fang Kang,Xiaoxiao Zhang
Dielectric capacitors with a high energy-storage density and efficiency are urgently required for miniaturization and integration of power electronics and pulsed power system. Herein, single-layered stretched P(VDF-HFP) with a certain content of poly(methyl methacrylate) (PMMA) and two kinds of sandwich-structured films are prepared to optimize and compare energy-storage performance. The results revealed that the crystallization transition behavior of stretched P(VDF-HFP) films contributed to enhance its electric polarization, while the introduction of linear type PMMA resulted in an enhancement of voltage tolerance of stretched films by improving the mechanical properties and suppressing leakage current. What’s more, the effects of crystalline orientations and structure design on the breakdown mechanism of stretched films were revealed by finite element theoretical simulation. As a consequence, the stretched sandwich-structured 0-25-0-S (pure P(VDF-HFP) serves as the outer layer, and blends represent the middle layer; the digit representing PMMA content in the P(VDF-HFP)) displayed a high Ue of 28.71 J/cm3 and η of 74% under 680 MV/m. This work provides a workable and effective method for developing capacitive films with great energy-storage performance.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
高影响因子
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