Materials
·
2018
·Vol. 11
·期 9
·1756
·
IF 2.467
Mi Zhang,Yu Gao,Yixing Zhan,Xiaoqing Ding,Ming Wang,Xinlong Wang
Degradable, flame retardant, and flexible nanocomposite films with low dielectric constant were prepared with poly (lactic acid) (PLA), nano ZIF-8@GO, and degradable flame-retardant resorcinol di(phenyl phosphate) (RDP). The SEM results of the fractured surfaces indicated that ZIF-8@GO and RDP were dispersed uniformly in the PLA matrix. The prepared films had good mechanical properties and the tensile strength of the film with 1.5 wt% of ZIF-8@GO was increased to 48.2 MPa, compared with 38.5 MPa of pure PLA. Meanwhile, the nanocomposite films were flexible due to the toughing effect of RDP. Moreover, above 27.0% of limited oxygen index (LOI) and a VTM-0 rating were achieved for the nanocomposite films. The effects of nano ZIF-8@GO hybrids and RDP on the dielectric properties were investigated, and the results showed that ZIF-8@GO and RDP were beneficial in reducing the dielectric constant and dielectric loss of the nanocomposites.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE FORUM
·
2020
·
IF 0
Zhi Wei He,Hong Xiao Lin,Chun Yan Li,Ashok M. Mahajan,Swati A. Gupta,Mei Zhou
Effect of various silicon sources, such as TEOS, MTES mixed with TEOS and 1,3,5-tris(triethoxymethyl) on SiO2 films was investigated. The synthesized solutions were used as silicon sources to prepare silica-like backbone films. The investigation showed that all precursors can able to produce the flat and uniform films. An FTIR spectrum confirmed the formation of SiO2 in film matrix. The results indicated that the internal microstructure of each film is different. The incorporation of less polar bonds such as F and C was carried out using various Si sources, while the introduction of these sources confirmed through FTIR spectra. Optical properties of the films were carried out by using ellipsometric porosometry (EP) measurement. The leakage current density for the films prepared by using TEOS, MTES and 135TTEB was observed to be 2.8 × 10-7 A/cm2, 2.9 × 10-8 A / cm2, and 4.1 × 10-6 A / cm2, respectively, at 1 MV/cm electric field strength by the IV curves obtained by semiconductor characterization after fabricating MIS devices. The calculated dielectric constants from RI of the deposited SiO2 films were 2.0, 1.9 and 2.5 respectively. When the microstructure of the precursor solution changed, the introduction of atomic morphology or terminal inerted group ratio changed the internal bridging mode of SiO2, and thereby significantly reduced the dielectric constant and improved insulation.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Bing Liu,Ke Sha,Meng Fei Zhou,Kai Xin Song,Yu Hui Huang,Cheng Chao Hu
Two novel low- ε r gallates MGa 2 O 4 (M = Ca, Sr) have been synthesized via a standard solid-state reaction method. According to the X-ray diffraction results, CaGa 2 O 4 crystallizes in space group Pna2 1 with an orthorhombic symmetry, while SrGa 2 O 4 belongs to the monoclinic P2 1 / c system. Both ceramics show ever-improving microstructures with the increasing sintering temperature . The optimal microwave dielectric properties ( ε r = 9.2, Qf = 66,000 GHz, τ f =–85 ppm/°C for SrGa 2 O 4 and ε r = 10.6, Qf = 15,400 GHz, τ f =–58 ppm/°C for CaGa 2 O 4 ) are obtained when sintered at 1275 °C. A patch antenna is fabricated using SrGa 2 O 4 ceramics as the substrate, which realizes a return loss of –19.94 dB and total efficiency of –1.38 dB (72.8 % in power ratio) at 4.84 GHz. The exceptional performances indicate that SrGa 2 O 4 ceramics are promising candidates for antenna applications at the Sub-6 GHz band.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Weishuang Fang,Kai Cheng,Huicheng Xiang,Ying Tang,Yifan Zhai,Congxue Su,Liang Fang
It has become a focus to develop low-permittivity microwave dielectric materials to meet the needs of high-speed transmission in telecommunication devices. Here, we report two Ge-based microwave dielectric ceramics prepared using the conventional solid-state method, MgGeO 3 and ZnGeO 3 , with low permittivity of 6.8 and 6.6, the high-quality factor of 65,200 GHz and 25,200 GHz, and negative temperature coefficient of −45 ppm/°C and −35 ppm/°C. Orthorhombic ilmenite structure of MgGeO 3 can be obtained in the range of 1160–1240 °C. However, the single-phase ZnGeO 3 is not available in air, and the ceramics sintered at 1040–1120 °C contain two phases of Zn 2 GeO 4 and GeO 2 .
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
MACROMOLECULAR MATERIALS AND ENGINEERING
·
2020
·Vol. 305
·期 6
·2000063
·
IF 3.853
Yang Mo,Lijun Yang,Wei Hou,Tiantian Zou,Youyu Huang,Ruijin Liao
This study aims to decrease the dielectric constant of kraft paper by 1,2,3,4-butanetetracarboxylic acid (BTCA) esterification crosslinking. Kraft paper samples are treated with various concentrations of BTCA to prepare modified paper with different reaction degrees. Morphology and surface chemical composition are characterized. The dielectric constant and loss of the plain and modified paper are also investigated. Results show that esterification occurs successfully between cellulose molecular chain and BTCA. The intrinsic dielectric constant and loss of 6 g L −1 BTCA-treated paper decrease by 23.5% and 36.3%, respectively, at 50 Hz. The esterification can reduce the hydroxyl amounts on cellulose. The formed crosslinking network between the cellulose chains restricts the cellulose orientation polarization, thereby reducing cellulose polarizability. The electrical strength, mechanical properties, and thermal behavior of the samples are explored to evaluate comprehensively the modifying effect. BTCA esterification crosslinking proves to be a promising method for decreasing the dielectric constant of kraft paper.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 59
·期 4
·329-339
·
IF 0
Mengjie Hu,Haiquan Chen,Mengxia Wang,Gang Liu,Chunhai Chen,Guangtao Qian,Youhai Yu
Polyimides (PI's) with low-dielectric constant and excellent organic solubility have broad application prospects in the electronic field. Herein, this study designed a series of novel, low dielectric, organic soluble PI films by creatively introducing fluorene and pyridine ring into diamine monomers. Because of the noncoplanar structure of fluorenyl and the polarization of pyridine ring, PI films achieved a low-dielectric constant (2.22–3.09 at 10 MHz) and excellent organic solubility. Even in some organic solvents with low-boiling points, these PI films still exhibited outstanding solubility. In addition, all the films possessed high-tensile strength (≈120 MPa) and excellent optical transparency (>70%, 450 nm). It was worth noting that the glass transition temperature of films was all above 280°C and 5% weight loss temperature ( T 5% ) was at 486–553°C. In general, the novel high-performance low-dielectric PI films are expected to be used in the field of microelectronics. Graphical A series of novel, low dielectric, organic soluble PI films are synthesized by creatively introducing fluorene and pyridine ring into diamine monomers. Compared with traditional Kapton film, these new polyimides containing fluorenyl and pyridine heterocycles in the main chain have low-dielectric constants.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
Polymer-Plastics Technology and Materials
·
2020
·
IF 0
Guorong Qiu,Wenshi Ma,Li Wu
The thermoplastic and low dielectric constants polyimides were introduced. The polyimides were prepared by pyromellitic dianhydride (PMDA) or 4,4ʹ-(4,4ʹ-Isopropylidenediphenoxy)diphthalic anhydride (BPADA) as anhydride monomer and 4,4ʹ-oxydianiline (ODA) or 2,2-bis(4-(4-aminephenoxy)phenyl)propane (BAPP) as amine monomer. The polyimides were well characterized by FT-IR, thermogravimetric analysis, dynamic thermomechanical analysis, dielectric measurement, and tensile test. The dielectric constants were 2.32–2.95 compared with 3.10 of ODA-PMDA polyimide, while partly polyimides were thermoplastic. The results indicated anhydride monomers, containing lateral methyl groups, made polyimides become thermoplastic. The results of molecular simulations via Materials Studio also proved this conclusion.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Chun Tong,Xinlei Shen,Xia Feng,LiFeng Ding,Haikui Zhu,Lixi Wang
Ca 1- x Sr x B 2 O 4 ( x = 0–0.5) ceramics are prepared using the conventional solid-state method, and their crystal structure, microstructure, microwave dielectric properties, and low-temperature co-firing characteristics are systematically studied. To enhance the crystalline structure order, this study aims to improve the sintering performance of CaB 2 O 4 by forming a solid solution with Sr 2+ substituting Ca 2+ sites. X-ray diffraction results indicate that with the doping of Sr 2+ , the unit cell volume of Ca 1- x Sr x B 2 O 4 ceramics increases, and the diffraction peaks shift to lower angles. EDS results confirm that Sr 2+ is uniformly distributed in the Ca 1- x Sr x B 2 O 4 ceramics, successfully forming a solid solution. SEM analysis reveals that an appropriate amount of Sr 2+ improves grain uniformity and reduces porosity between grains. Raman spectroscopy shows that moderate Sr 2+ doping enhances the order of the crystalline structure, leading to an increase in the Q × f value of the ceramics. When x = 0.03 and the sintering temperature is 900 °C, Ca 1- x Sr x B 2 O 4 ceramics exhibit optimal microwave dielectric properties: ε r = 5.53, Q × f = 33,135 GHz, τ f = −27.37 ppm/°C. During co-sintering with Ag electrodes, Ca 1- x Sr x B 2 O 4 ceramics show excellent chemical compatibility with Ag powder, with no silver diffusion observed. This demonstrates the great potential of Ca 1- x Sr x B 2 O 4 ceramics for LTCC applications.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1403
·
IF 3.164
Lifen Tong,Xiting Lei,Guangyao Yang,Xiaobo Liu
A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.Keywords:low dielectric constant;poly(arylene ether nitrile);thermal properties;self-toughening;self-enhancement
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER INTERNATIONAL
·
2020
·Vol. 69
·期 5
·485-491
·
IF 2.574
Guorong Qiu,Wenshi Ma,Li Wu
Polyimide microspheres were prepared via non-aqueous emulsion polymerization by using pyromellitic dianhydride (PMDA) as anhydride monomer and 2,2-bis(4-(4-aminophenoxy)phenyl)propane as amine monomer. The polyimide microspheres were well characterized by Fourier transform infrared spectroscopy, SEM and laser particle size analyzer. They were spherical in shape and monodisperse and their size was 31–33 μm. Polyimide mixtures formed by polyimide microspheres as fillers and polyimide composed of pyromellitic and dianhydride 4,4′-oxydianiline (ODA) as matrix were investigated with regard to thermal properties, dielectric properties and mechanical properties. With 10%–50% polyimide microspheres in the polyimide mixtures, the dielectric constants were 2.26–2.48 (1 MHz) and the loss tangents were 0.00663–0.00857 (1 MHz), which were both significantly lower than the values for ODA-PMDA polyimide. The decomposition temperature and glass transition temperature were above 440 and 290 °C. The polyimide mixtures possessed excellent thermal resistance. When the percentage of polyimide microsphere addition was 30%, the polyimide mixtures had the largest tensile strength (128.50 MPa) and elongation at break (9.01%). These results indicate that the polyimide microspheres were used as both low dielectric fillers and reinforcing fillers. © 2020 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 13
·2853
·
IF 5
Yurong Zhang,Haidan Lin,Kai Dong,Shasha Tang,Chengji Zhao
A series of epoxy resins containing various trifluoromethyl groups were synthesized and thermally cured with diaminodiphenylmethane (DDM) and aminophenyl sulfone (DDS). All epoxy resins exhibited excellent thermal stability with the glass transition temperatures of above 128 °C and 5% weight loss temperatures of above 300 °C. DDS-cured epoxy resins possessed higher thermal stability than that of DDM-cured epoxy resins, while DDM-cured epoxy resins showed better mechanical, dielectric, and hydrophobic properties. Additionally, DDM-cured epoxy resins with different locations and numbers of trifluoromethyl groups showed flexural strength in the range of 95.55~152.36 MPa, flexural modulus in the range of 1.71~2.65 GPa, dielectric constant in the range of 2.55~3.05, and water absorption in the range of 0.49~0.95%. These results indicate that the incorporation of trifluoromethyl pendant groups into epoxy resins can be a valid strategy to improve the dielectric and hydrophobic performance.Keywords:trifluoromethyl substitution;low dielectric constant;hydrophobicity;thermal stability
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 11
·1-12
·
IF 2.8
Li Heming,Wang Xinming,Gong Yuze,Zhao Hongbin,Liu Zhaobin,Tao Lin,Dastan Davoud,Ma Ke,Hu Zhizhi,Sun Mingming
In the area of Polymer dielectric materials, those with low dielectric constant and low dielectric loss have potential to be applied in high-frequency signal transmissions, such as antennae of mobile phones and millimeter-wave radars. This study is focused on producing fluorinated polyimide (PI) film with modified organosilicon (APDS). In this work, APDS was used to PI film. The spatial hindrance of Trifluoromethyl can reduce the high frequency dielectric loss of modified PI film. The length of molecular chain was decreased as increasing the proportion of APDS, which reduced the quantity of polar imide rings in unit volume. Meanwhile, the Si-O-Si bond combination in backbone decreased the integer polarity of PI film, which resulted in the decrease of tan ?. The values of ε and tan ? were 2.48 and 0.00335 respectively under 10 GHz. The values of ε and tan? were reduced to 6.6% and 36.5% respectively compared with base membrane. Thus, this work provides a simple method to reduce the dielectric constant and dielectric loss of PI film. Meanwhile, the relationship between dielectric properties and molecular structure was proved. PI molecules were separated by low dielectric groups, which resulted in a decrease in dielectric constant and dielectric loss.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）