Royal Society Open Science
·
2019
·Vol. 6
·期 5
·
IF 2.515
Yucheng Chang,Yongming Luo,Caihong Xu,Jianling Zhao
Polysilazane (PSN2) was used as chemical foaming agent to prepare epoxy foam for the first time. Using the new foaming agent, epoxy foams with high strength and low density were successfully prepared. The density of epoxy foam can be tuned from 0.321 to 0.151 g cm−3 by changing the content of PSN2 from 2.50 to 7.50 wt%, with the compressive strength varied from 7.39 to 1.25 MPa. The morphology, porosity, mechanical property, thermal conductivity and adhesive property of foams with different polysilazane content were investigated. Besides, the effect of polyamine curing agent and surfactant on foams was also investigated to optimize the as-prepared epoxy foam.
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 APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 24
·e55502
·
IF 2.7
Haiwen Tang,Yi Li,Ziyi Zhu,Yingqing Zhan,Ying Li,Kui Li,Pan Wang,Fei Zhong,Wei Feng,Xulin Yang
Previous studies on epoxy foams were subjected to the specific property, and improvements in thermal insulation or dielectric property were usually accompanied by the sacrifice of mechanical strength or thermal stability. The current research reported a high-performance epoxy foam by the pre-curing process using E-51/DDS and expandable microsphere (EMP) as polymer matrix and physical blowing agent, respectively. The effect of EMP loading on the structure & property of epoxy foam was reported. The mean diameter of E-51/EMP foam was in the range of 19–21 μm. The compression property of E-51/EMP foam was fit for the power-law model and its integrity was well maintained during compressive test. Compared with bulky epoxy, a significant decrease of thermal conductivity of 62.93% was observed in 10 wt% EMP-filled epoxy foam. E-51/EMP foam showed superior thermal stabilities, with a T 5% of over 300°C. The dielectric constant was decreased by 54.5% from 4.92 in bulky epoxy to 2.24 in E-51/EMP foam (10 wt% EMP). Notably, there was a percolation phenomenon of EMP (6 wt%) regarding on the structure & property of E-51/EMP foam. This study provides lightweight, robust, high-temperature-resistant, and low-dielectric-constant epoxy foams with the wide application prospects in buoyant, electronic packaging, and energy-saving industries.
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
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xun Fan,Guangcheng Zhang,Qiang Gao,Jiantong Li,Zhengyang Shang,Hongming Zhang,Yu Zhang,Xuetao Shi,Jianbin Qin
In this work, epoxy foams with high volume expansion ratio and excellent electromagnetic interference (EMI) are fabricated by the supercritical carbon dioxide as blowing agent. So far, the volume expansion ratio of about 20 for epoxy foam reported in this work is the highest in literature and reported for the first time, related to the strategy of introducing hyperbranched epoxy and solvent-free covalent nanofluid hybrid material of nanocarbon black as modifier and nucleated agent. Meanwhile, incorporating commercial silver nanosheet (AgNS) into above-foamed system achieves two synergistic effects: one is the significant increase of electrical conductivity and the other is the well controllable cell structure to avoid cell coalescence. In turn, the uniform cell distribution of epoxy foams is favorable for the formation of more efficient conductive networks related to the biaxial stretching on rearrangement in the cell wall and inter-connection of AgNS. Multi-properties including electrical conductivity of 89.12 S/m, specific EMI SE (SSE) of 334.59 dB·cm 3 /g and thermal conductivity of 58.71 mW/m·K are achieved in the epoxy composite foam with 20.0 wt% AgNS. The EMI mechanism is dominated by absorption rather than reflection due to electromagnetic waves attenuated by AgNSs in cell walls after the waves reflecting several times in cells. This work provides SCCO 2 foaming strategy as a feasible path to generate epoxy conductive polymer composite (CPC) foam with lighting weight, low thermal conductivity, outstanding electrical conductivity, excellent EMI SE and accessible mechanical strength.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Composites Science
·
2025
·Vol. 9
·期 1
·15
·
IF 3.7
Anton Mostovoy,Amirbek Bekeshev,Andrey Shcherbakov,Arai Zhumabekova,Zhadira Nurtai,Marina Lopukhova
As a result of the conducted studies, the method of combining components and foaming parameters for obtaining foam epoxides has been selected. The relationship between the structure of the foam epoxide and the amount of the added blowing agent—ammonium carbonate—has been established. This study explores the development of fire-safe foamed epoxy composites by incorporating technogenic waste from ceramic brick production. The optimized composites demonstrated improved compressive strength, enhanced fire resistance (the LOI—35–44%—and successful UL-94 V-0 testing) through the use of flame retardants (Tris(2-methylphenyl) phosphate and Decabromodiphenyl oxide) and low thermal conductivity (0.030–0.042 W/m K), highlighting their potential as sustainable thermal insulation materials.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 24
·3549
·
IF 4.7
Tienan Dong,Jingru Quan,Funing Huang,Yitong Guan,Zihong Lin,Zeyao Wang,Yuheng Liu,Zusheng Hang,Yupei Zhao,Yu’an Huang
In this study, CO2reacted with a curing agent through nucleophilic addition to form ammonium salts, enabling the stable capture and internal release of CO2, which achieved gas-phase nucleation and foaming. Additionally, the introduction of wave-absorbing agents improved the absorption mechanism and promoted uniform foaming. This nucleation-free foaming process relies on the induced growth of gas nuclei and the synergistic effect of the wave-absorbing agents, effectively preventing the uneven foaming issues caused by traditional nucleating agents. Ultimately, a lightweight epoxy foam absorbing material (LFAM) was developed. BET tests showed that 2.0 wt% carbon-based wave-absorbing agents (LFAMs–A2) expanded the material’s volume to 4.6 times its original size, forming a uniform porous structure. VNA tests revealed that LFAMs–A2 achieved a minimum reflection loss of −13.25 dB and an absorption bandwidth of 3.7 GHz in the 12–18 GHz range. The material with 2.0 wt% ferrite-based wave-absorbing agents (LFAMs–C2) achieved a minimum reflection loss of −26.83 dB at 16.6 GHz and an absorption bandwidth of 5.3 GHz, nearly covering the Ku band. DSC tests indicated that the material maintained good thermal stability at 150 °C. This study provides a new approach for lightweight coatings and structural optimization, with broad application potential in 5G communications, microwave anechoic chambers, and aerospace fields.
研究领域:
材料科学
·
电磁学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2019
·
IF 4.191
Xujuan Huang,Xinxin Yang,He Liu,Shibin Shang,Zhaosheng Cai,Kang Wu
Bio-based thermosetting epoxy foams were synthesized via an epoxide ring opening reaction of epoxidized soybean oil (ESO) with fumaropimaric acid (FPA) by using N, N-dimethylbenzylamine as the catalyst and sodium bicarbonate as the foaming agent. The reactivity of the ESO/FPA polymeric matrix became stronger as the proportion of FPA increased. Thermal gravimetric (TG) analysis showed that these thermosetting epoxy foams had high thermal stability. The introduction of the rigid hydrogenated phenanthrene ring structure of FPA improved the viscosity of the ESO/FPA polymeric matrix and the cell wall structure of the foams. Therefore, the apparent density of foams decreased from 361 to 231 kg/m 3 with the increase in FPA content in the ESO/FPA polymeric matrix. The compressive modulus (E * ) and compressive strength ( σ c ) of the foams improved due to the rigid hydrogenated phenanthrene ring structure of FPA. Furthermore, the foam could be adjusted to become flexible foam or rigid foam by changing the molar ratio of the ESO/FPA polymeric matrix. Foams with low apparent density, high porosity, and closed cells had a lower thermal conductivity coefficient which decreased to 0.031 W/(m·K).
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
COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Xun Fan,Qiang Gao,Yu Zhang,Jianbin Qin,Yongsheng Zhao,Xuetao Shi,Guangcheng Zhang
Carbon aerogel shows great potential in electromagnetic interference shielding (EMI) application and is generally strengthened by epoxy impregnation for harsh working environment. However, it is still challenging to simultaneously achieve high mechanical robustness and EMI performance, especially taking low-cost and light-weight feature into account. In this work, a “gelation-press drying-impregnation & micro-foaming” method was systematically reported to target microcellular epoxy foam containing hybrid reduced graphene oxide (rGO)/short-carbon-fiber (SCF) aerogel . Herein, aerogel morphology was transformed from isotropic honey-comb structure into anisotropic corrugated structure by controllable press air-drying. A further supercritical carbon dioxide (scCO 2 ) foaming process was implemented for density reduction. Moreover, the anisotropic microcellular epoxy(m-EP)/rGO-SCF foam (D = ∼0.48 μm, N f = 5.02 × 10 12 cell/cm 3 ) shows low density (1.14 g/cm 3 ), high electrical conductivity (2365.0 S/m), enhanced compressibility (σ b = 243.0 MPa, ε b = ∼45%) and outstanding EMI shielding effectiveness (95.5 dB) with a low thickness (2.0 mm) within X band (8.2–12.4 GHz). Therefore, our work provides a universal step-by-step and industrial-friendly approach to fabricate light-weight carbon-aerogel-based foams with anisotropic carbon structure and outstanding EMI performance.
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
危险品化学品经营许可证（带存储）