ACS Applied Polymer Materials
·
2023
·
IF 5
Yi Liu,Ling Yuan Liao,Wen Hong Ruan,Ming Qiu Zhang,Li Weihao
With the soaring development of device integration, miniaturization, and high frequency, electric devices have put forward synchronous and urgent requirements for thermal management composites with insulation, high thermal conductivity (TC), and low dielectric properties. However, due to phonon scattering and interfacial polarization, these performance requirements are difficult to meet simultaneously. In this work, based on the principles of interfacial engineering, hexagonal boron nitride (BN) was functionalized with methylvinyldimethoxysilane (MVDMS), and poly(phenylene oxide) (PPO) was modified by methacrylic anhydride. Owing to the introduction of reactive groups, the reaction between modified BN (BN@Si) and modified PPO (MPPO) in the mixing process enhances the interfacial forces, improves filler dispersions, and helps to reduce phonon scattering and interfacial polarization. The resulting polymer composites have a high TC of 5.21 W/(m K) at 70 wt % filler loading, 20.7 times than that of the pure MPPO resin, low dielectric loss of 0.00252, and high thermal stability. It is shown that interfacial regulation is crucial for BN@Si/poly(phenylene oxide) composites. The obtained composites hold great potential as thermal management materials for 5G electronic devices.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2023
·
IF 3.9
Honghui Xiong,Jinglei Liu,Yongjun Zhang,Hao Wang,Enhao Sun
To reduce the coke formation, a novel Al/Si/Cr/Ce composite ceramic coating was prepared on the surface of the Cr 25 Ni 35 Nb alloy substrate by pack cementation. The microstructure, phase composition, surface morphology and element distribution of substrate and coating were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results reveal that the outer layer of the coating forms a protective layer with a high proportion of AlN and Cr 3 Si and trace amounts of Ce. The inter-diffusion layer is mainly aluminide coating (AlNi and AlFe) and transition layer contains a small amount of AlN. The anti-coking performance of the coating was assessed using naphtha steam cracking. To study coking behavior, the morphology and microstructure of the coke layer were analyzed and characterized by SEM and Laser Micro-Raman Spectrometer. The coke layer on uncoated sample has a higher focal density and is more likely to spall and peel off when subjected to coking experiment. A large number of filamentous and granular cokes appear on the surface of the uncoated sample, whereas only less granular cokes appear on the surface of the coated sample, and the coke on the uncoated sample has a more disordered and amorphous carbon structure. The coating significantly inhibited the growth of filamentous coke and reduced coke accumulation.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Kaibo Pan,Zhicheng Zhu,Chongming Liu,Songyuan Tao,Xiaoduo Tang,Xiaoyu Wei,Bai Yang
Flexible transparent hydrophobic coating films with excellent scratch resistance have important applications in many fields, especially for optical materials. Herein, a hydrophobic composite coating film was prepared and used as a polymer film protective material by combining 3-glycidyloxypropyltrimethoxysilane (GPTMS)-modified Si-doped carbonized polymer dots (Si-CPDs) with mono-trimethoxysilyl-terminated poly(dimethyl siloxane) (PDMS). The Si-CPDs derived from tetramethyl disiloxane propylamine tetraacetic acid and multi-amino oligosiloxanes were successfully prepared via one-step hydrothermal method and then grafted by GPTMS to obtain modified Si-CPDs (mSi-CPDs). Among them, mSi-CPDs act as a matrix layer, and PDMS acts as a low-surface energy layer. Cross-linking the Si–O–Si network of the coating film was formed through sol–gel chemistry. Driven by the hydrophilic–hydrophobic effect, PDMS trends to aggregate at the film surface, thus avoiding the phase separation which can affect transparency. The highly cross-linked network and the presence of hard silica core provide a high hardness to stand the steel–wool scratch. Flexible polymer chains impart the coating film an outstanding bendability. Introduction of PDMS makes the coating film possess hydrophobicity and anti-graffiti function.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2023
·Vol. 15
·期 10
·2384
·
IF 5
Siyuan He,Cheng Chi,Chaohua Peng,Birong Zeng,Yongming Chen,Zhongxi Miao,Hui Xu,Weiang Luo,Guorong Chen,Zhenping Fu,Lizong Dai
It is still extremely challenging to endow epoxy resins (EPs) with excellent flame retardancy and high toughness. In this work, we propose a facile strategy of combining rigid–flexible groups, promoting groups and polar phosphorus groups with the vanillin compound, which implements a dual functional modification for EPs. With only 0.22% phosphorus loading, the modified EPs obtain a limiting oxygen index (LOI) value of 31.5% and reach V-0 grade in UL-94 vertical burning tests. Particularly, the introduction of P/N/Si-containing vanillin-based flame retardant (DPBSi) improves the mechanical properties of EPs, including toughness and strength. Compared with EPs, the storage modulus and impact strength of EP composites can increase by 61.1% and 240%, respectively. Therefore, this work introduces a novel molecular design strategy for constructing an epoxy system with high-efficiency fire safety and excellent mechanical properties, giving it immense potential for broadening the application fields of EPs.Keywords:flame retardant;vanillin;epoxy resin;synergistic effect;strength and toughness
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2023
·
IF 8.7
Wei Wang,Xiangyu Jin,He Huang,Shuang Hu,Can Wu,Hebing Wang,Yiwu Pan,Changqing Hong,Xinghong Zhang
Ablative thermal protection systems are considered to be one of the most promising means of protection for spacecraft re-entry, but challenges remain. Herein, efficient Ti-Si binary modified carbon fiber reinforced phenolic aerogel nanocomposites (C f /TS-PR) were originally designed based on a multi-stage construction strategy. The C f /TS-PR exhibited desirable mechanical strength , good thermal insulation with a minimum thermal conductivity of 0.0756 W/(m·K), remarkable thermal stability and outstanding ablation resistance, benefiting from the features of TiO 2 and the special structure of TiO 2 -SiO 2 coating. The linear ablation rates are as low as 0.004 and 0.003 mm/s at the heat flow of 1.0 and 1.5 MW/m 2 , respectively. The mass loss rates are as low as 0.006 and 0.009 g/s at the heat flow of 1.0 and 1.5 MW/m 2 , respectively. These results indicate that the C f /TS-PR nanocomposites can be a reliable thermal protection material for the future high-temperature service environment of ultra-high-speed vehicles and neutral rockets.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 30
·期 2
·1626-1636
·
IF 2.324
Li Yuexuan,Duan Yugang
Silicon coupling reagent is regarded as a common additive on surface treatment of polymer due to its high bonding strength and low cost. In this paper, a series of γ-(2, 3-epoxypropoxy) propyltrimethoxysilane (KH560)-based reduced graphene oxide (RGO)@Fe 3 O 4 (KH560/RGO@Fe 3 O 4 ) composites with different ratio of Fe 3 O 4 nanoparticles (NPs) are synthesized by a facile hydrothermal method. It is confirmed that the silicon reagent KH560, as a hopeful candidate for increasing the RGO lattice defects, is favorable to improve the electromagnetic wave absorption. Meanwhile, the microwave attenuation mechanism of KH560/RGO@Fe 3 O 4 composite suggests that the dielectric loss mainly causes by multiple Debye dipolar relaxation and its magnetic loss comes from the eddy-current effect of Fe 3 O 4 NPs over the high frequency range. In consequence, the KH560/RGO@Fe 3 O 4 composite endows the excellent absorption performance, the reflection loss (RL) value is optimized to − 25 dB at 14.1 GHz with a thickness of 3 mm and the maximum frequency bandwidth for RL < − 10 dB is 4.1 GHz with a thickness of 4 mm.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Qingze Chen,Runliang Zhu,Liangliang Deng,Lingya Ma,Qiuzhi He,Jing Du,Haoyang Fu,Junping Zhang,Aiqin Wang
A low-cost and scalable strategy for the synthesis of the hierarchically porous and hydrophobic adsorbent for volatile organic compounds removal remains a challenge. In this work, a novel silicon/silicon oxide (Si/SiO x ) composite with hierarchical porosity and hydrophobicity was successfully designed from natural palygorskite via a one-pot synthesis strategy, which could be promising in the scalable production due to the cost-effective precursor and simple procedure. The insufficient reduction of palygorskite during the molten salt-assisted magnesiothermic reaction led to the formation of hydrophobic crystalline silicon and the maintenance of amorphous silica framework. The results showed that the Si/SiO x composite possessed the large specific surface area (~307 m 2 g −1 ) and hierarchically porous structure ( i.e. , micro-, meso-, and macropores). As adsorbent for benzene molecules, the Si/SiO x composite exhibited much better static and dynamic benzene adsorption capacities (585.7 and 316.2 mg g −1 , respectively) than raw palygorskite (265.7 and 166.1 mg g −1 , respectively). The excellent benzene adsorption performance of the Si/SiO x composite could be attributed to the large specific area (offering ample adsorption sites) and hierarchical porosity (facilitating the diffusion/mass transfer process). Moreover, the Si/SiO x composite maintained a high adsorption capactiy for benzene under humidity condition (238.7 mg g −1 , with the adsorption efficiency of 76%). Our work provided a universal one-pot method from clay mineral to the hierarchically porous and hydrophobic Si/SiO x composite, and this novel product could be used as an attractive adsorbent for the practical removal of volatile organic compounds.
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2018
·Vol. 15
·期 5
·1146-1156
·
IF 1.165
Qingliang Shan,Jianbao Hu,Yanmei Kan,Dewei Ni,Le Gao,Xiaowu Chen,Shaoming Dong
Si-B-C ceramics were prepared through reaction sintering, and the influence of Al 2 O 3 addition on the high-temperature (1100-1300°C) oxidation behavior of the material under air atmosphere was studied. The erosion behavior and mechanism are determined from the measurement of weigh changes, microstructure observations, and characterization of the generated oxides on postexposure specimens. Results show that Al 2 O 3 is enriched in the oxidized layer, inhibiting the volatilization of B 2 O 3 and impeding the crystallization ability of oxide (cristobalite). Narrower erosion layer and less weigh change are observed with Al 2 O 3 . Low-frequency Raman results reveals that with the increase in Al 2 O 3 , the bending vibrations of the BO 4 units and B-O-B stretching of the metaborate ring relative intensity are enhanced. Furthermore, high-frequency Raman results shows that the relative proportion of high-dimensional vibration modes Q 3 and Q 4 which result in a higher viscosity of melt and a greater resistance of oxygen diffusion are positively correlated with Al 2 O 3 .
✓ 已验证
产品关联
DOI
高影响因子
Nano Research
·
2018
·Vol. 11
·期 12
·6294-6303
·
IF 7.994
Han Ying,Zhou Jie,Li Tieqiang,Yi Zheng,Lin Ning,Qian Yitai
Two-dimensional (2D) materials have attracted enormous attention due to their functional applications in energy storage. In this work, a low-temperature molten-salt chemical exfoliation methodology is developed for producing free-standing 2D mesoporous Si through deintercalation of CaSi 2 in excess molten AlCl 3 at 195 °C. The average dimension of these sheets is 1.5 μm, and the thickness of a single sheet is approximately 10 nm. The as-prepared 2D Si has a Brunauer–Emmett–Teller surface area of 154 m 2 ·g −1 and an average pore size of 5.87 nm. With this unique structure, the 2D Si exhibits superior Li-storage performance, including a reversible capacity of 2,974 mA·h·g −1 at 0.2 C, reversible capacities of 2,162, 1,947, and 1,527 mA·h·g −1 at 0.8, 2, and 5 C after 200 cycles, and a capacity retention of 357 mA·h·g −1 even at 30 C (90 A·g −1 ).
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yiming Zhao,Lihua Zheng,Hao Wu,Huan Chen,Liwei Su,Lianbang Wang,Yuanhao Wang,Manman Ren
Tetravalent Si materials (SiO 2 and transition metal silicates) are receiving tremendous attentions for lithium storage, whereas a troublesome problem is how to improve the content of active Si. This work reports a novel method to boost their lithium storage capabilities by using highly-dispersed Co element in the form of nanofilm-like Co 2 SiO 4 /SiO 2 powder on the surface of reduced graphene oxide (RGO) that promotes the electronic diffusion and accommodates the volume changes. As a result, the Co 2 SiO 4 /SiO 2 /RGO exhibits over 20 times higher reversible capacity and better rate performance than the SiO 2 /RGO counterpart. In comparison, the Co 2 SiO 4 /SiO 2 /RGO shows the highest reversible capacity (1382 mAh g −1 at 500 mA g −1 ) and longest life span (500 cycles) in all known silicates-based materials and higher power/energy density than both of commercial graphite and Li 4 Ti 5 O 12 materials. Ex-situ X-ray photoelectron spectra and electrochemical tests at different voltage windows are conducted to illustrate the reason for the significantly improved performances. It demonstrates that tetravalent Si is gradually activated to lower-valence form by highly-dispersed Co generated with cycling. This observation provides new evidence for the electrochemical catalytic mechanism in transition metal silicates for lithium storage.
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2024
·
IF 10.9
Binmeng Chen,Xu Fang,Yuyang Zhao,Zongjin Li
In recycling and reusing construction waste, carbonation of recycled concrete fine (RCF) has been successfully applied to produce value-added products, such as silica nanoparticles, via the breaking of calcium silicate hydrate (C-S-H) structure and condensation of silicate chains. However, the intricacies of carbonation of RCF with varying calcium to silicon (C/S) ratios and their implications on the size of generated silica nanoparticles remain unknown. In this work, we developed an optimized carbonation method at high water to solid ratio to fabricate silica nanoparticles from C-S-H with different C/S ratios. The particle size of silica nanoparticles was found to gradually decrease with the increased C/S ratio of C-S-H. Since as C/S ratio increased, silicate in Q 3 state shifted to Q 1 state and the silicate chain became shorter, shifting from long-range, disordered to short-range, ordered. As the disordered self-seeding growth of long silicate chains derived from C-S-H continued, the Si-O-Si network of silica nanoparticles became chaotic, leaving more unreacted Si-OH on its surface. On the contrary, the short silicate chains displayed higher possibility of condensation, making nanoparticles with a smaller diameter.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Jing Wang,Jian Hao,Xiao Yang,Ruyi Zhang,Junli Guo,Yu Zhao,Jianing Chen,Caixia Chi
In order to overcome the problems about the volume expansion and poor electronic conductivity of Si , a flexibility and rigidity double coating layer CNTs-rGO- PAIN was constructed. The CNTs-rGO-PANI network with porous structure and high electronic conductivity provides sufficient space to accommodate the volume change of Si, and abundant transmission path for electron and Li ion . Moreover, the coating network with flexibility and rigidity characteristic could absorb the expansion stress of Si, maintain electrode structural integrity, promote the growth of stable SEI . The polymer-nanocarbon network dual coating layer effectively safeguards the electrochemical-mechanical interplay within the electrode. The 20Si-CNTs-rGO-PANI exhibits a reversible capacity as high as 1856 mAh g −1 after 400 cycles at 0.2 A g −1 and a remarkable rate capacity of 570 and 459 mAh g −1 , at 5 and 10 A g −1 , respectively. The outstanding Li ion storage performance of 20Si-CNTs-rGO-PANI anode, suggests the flexibility-rigidity dual coating layer strategy is a potential way to improve the performance of alloy type anode .
✓ 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）