Nanotechnology Reviews
·
2020
·Vol. 9
·期 1
·209-218
·
IF 3.639
Jie Ding,Zhiying Qin,Haitao Luo,Wei Yang,Yanbing Wang,Zhixiong Huang
Nano-silica modified phenolic resin film is prepared using different mass fractions of nano-silica by liquid composites molding (LCM). The effects of nano-silica on the rheology and curing of phenolic resin are studied by rheometer and differential scanning calorimeter (DSC). The results show that the viscosity of nano-silica modified phenolic resin decreases with the increase of temperature, and the viscosity is lowest between 70°C and 90°C. The appropriate resin film infusion (RFI) process is investigated, and the stepped curing process system is established. In addition, the microstructures of modified phenolic film and composites are tested by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Nano-silica can be uniformly dispersed in phenolic resin when the amount of nano-silica added is ≤ 4%. And the mechanical properties of nano-silica modified phenolic composites are tested by universal material testing machine. The optimum nano-silica mass loading for the improvement of mechanical properties is found. This work provides an effective way to prepare the modified phenolic resin film suitable for resin film infusion (RFI) processes, and it maybe become a backbone of thermal protection material in aerospace.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 70
·65533-65540
·
IF 3.289
Hongxing Dong,Yonghe Li,Jin Zhang,Lijia Liu,Liying Cao,Pingjian Ming,Wenjing Liu,Chunhong Zhang,Lianhe Liu,Hao Wei
In order to reduce the effect of the thermal shock that occurs during the curing process of epoxy resin (EP), and to improve the mechanical properties of the cured EP, a novel curing procedure for an epoxy resin system, sodium carboxymethyl cellulose (CMC)/E51 type epoxy resin (E51)/4,4-diamino diphenyl methane (DDM), was established according to the simulated results of a three-dimensional finite element model and extrapolation method. Compared to the conventional curing procedure, a cooling stage was used in the new procedure according to the simulated results to reduce the effect of the thermal shock. The experimental verification showed that even when the curing time was 30 min shorter than the conventional procedure, the new curing procedure clearly improved the mechanical properties of the cured resin. For instance, the bending strength of the specimen cured by the new procedure reached 136 MPa, which is increased by 46% when compared to the specimen cured by the conventional procedure (93.3 MPa) and the impact strength increased from 18.3 kJ m−2 to 23.1 kJ m−2.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Tianyu Zhu,Chunxiang Lu,Xiaoxuan Lu,Jieying Zhi,Yingjun Song
A new epoxy-terminated hyperbranched polyether sulfone (EHPES) has been synthesized by a facile one-step method using 4,4′-dihydroxydiphenylsulfone (monomer A 2 ) and trimethylolpropane triglycidyl ether (monomer B 3 ). The diglycidyl ether of bisphenol-A (DGEBA) was modified by EHPES through the optimal curing process. Compared with the unmodified DGEBA, the copolymer containing 7% EHPES showed the best comprehensive performance. The maximum tensile, flexural, and impact strengths were increased by 9.24%, 10.70%, and 19.38%, respectively. The tensile and flexural moduli were enhanced by 40.74% and 16.20%, respectively. The excellent performances were attributed to the good compatibility of EHPES, increased rigidity, more free volumes, and more “flexible” crosslinking points. Meanwhile, the outstanding tensile property led to the narrow strain concentration region of DGEBA/7% EHPES copolymer through the observation of digital image correlation (DIC) system. The EHPES modified epoxy resin can also be potentially used for carbon fiber reinforced composites in some advanced applications.
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
Applied Sciences-Basel
·
2020
·Vol. 10
·期 14
·4857
·
IF 2.474
Xin Li,Hongyu Dong,Shaoqing Guo,Liangfu Zhao
Adhesion strength is of great importance for silver paste of heterojunction solar cells (HJT silver paste). It has a close relation with the curing system, as well as the curing process or curing conditions of the paste. The interactions among all the curing conditions such as curing time (t, min), treatment temperature (T, °C), and curing agent dosage (m, wt%) are obviously complex and hard to analyze. Response surface methodology (RSM) is used to research the interactions among t, T, and m and to optimize the curing process. The results of this study indicate that an increase of curing time and treatment temperature both had a positive effect on adhesion strength. The effect of curing time is more obvious under a lower treatment temperature. 41 wt%, 199 °C, and 44 min were determined as the optimum process conditions. The quadratic model predictions fitted well with the experimental data with a deviation less than 3%. The FTIR results indicated that there were both addition and esterification processes in the reaction of E51 and ring-open MeTHPA. Scanning electron microscopy (SEM) images showed that the silver paste formed a dense interconnected network and provided a continuous pathway for current carrier transmission. This research demonstrated the effectiveness of the E51-MeTHPA system for HJT silver paste and the superiority of RSM in studying the curing process of silver paste.Keywords:HJT silver paste;curing process;response surface methodology;adhesion strength
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Fuping Li,Yue Wang,Wei Dang,Zhuoli Xu,Xinyuan Zhang,Bo Zhang,Kang Zhao,Yufei Tang
Polycarbosilane-derived (PCS-derived) coatings were fabricated on iron substrate by dip-coating method. The effects of curing process including air curing and divinylbenzene (DVB) curing and pyrolysis temperature on the coating microstructure, adhesion and corrosion resistance in 3.5 wt% NaCl solution were systematically studied. Both curing process and pyrolysis temperature have a significant influence on the micro-cracks, surface roughness and ceramicization of the coatings. PCS-derived coatings fabricated by air curing process has the lower micro-crack width due to the higher curing degree. No matter in which curing process, the average micro-crack width and surface roughness of the coatings pyrolyzed at 600 °C are higher than those of the coatings pyrolyzed at 400 °C or unpyrolyzed. Electrochemical test results indicate that all coatings can protect the iron substrate from corrosion. The corrosion resistance of the PCS-derived coating is dominated by the microstructure including micro-cracks, surface roughness and ceramicization. Coatings fabricated through air curing and pyrolyzed at 400 °C have better corrosion resistance due to less micro-cracks, lower roughness and higher ceramicization. Corrosion resistance mechanism of the PCS-derived coatings was also analyzed.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 9
·2073
·
IF 5
Ruoqing Zhao,Hao Wu,Xuan Dong,Manzhang Xu,Zhenhua Wang,Xuewen Wang
High-quality and free-standing polyimide (PI) film with desirable mechanical properties and uniformity is in high demand due to its widespread applications in highly precise flexible and chip-integrated sensors. In this study, a free-standing PI film with high toughness was successfully prepared using a diamine monomer with ether linkages. The prepared PI films exhibited significantly superior mechanical properties compared to PI films of the same molecular structure, which can be attributed to the systematic exploration of the film-forming process. The exploration of the film-forming process includes the curing procedures, film-forming substrates, and annealing treatments. Additionally, the thickness uniformity and surface homogeneity of free-standing films were crucial for toughness. Increasing the crystallinity of the PI films by eliminating residual stress also contributed to their high strength. The results demonstrate that by adjusting the above-mentioned factors, the prepared PI films possess excellent mechanical properties, with tensile strength and elongation at break of 194.71 MPa and 130.13%, respectively.
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 COMPOSITES
·
2024
·
IF 4.8
Jianyang Yuan,Qihui Chen,Yong Gao,Jieyu Tai,Yaqing Liu
In terms of the interplay between manufacturing cost and quality during the molding of fiber reinforced thermosetting composites, this study proposes a multi-scale collaborative optimization strategy aimed at shortening molding time and reducing the diminishing defects generated during the process. Macro-scale thermochemical and micro-scale thermomechanical calculations are conducted on the composite molding to analyze the origins of temperature gradients and residual stresses. Then, the curing cycle, temperature gradient in the macro-scale model, and residual stresses in the micro-scale model are optimized by combining finite element analysis with the Non-dominated Sorting Genetic Algorithm II. Several curing processes within the Pareto front were selected, and their impact on compressive performance was assessed through experimental analysis. Compared to the standard curing process (SCP), the optimal curing process exhibited a 41.4% reduction in maximum temperature gradient (∆ T max ), a 25.2% de c rease in effective residual stress σ ¯ $$ \left(\overline{\sigma}\right) $$ , and a 20.0% increase in compressive strength. Multi-scale collaborative optimization strategies are integral to the advancement of production and application of fiber-reinforced thermoset composites. Multi-scale collaborative optimization strategies are integral to the advancement of production and application of fiber-reinforced thermoset composites. Highlights Investigated of interactions among components in composites molding. Optimization of composite molding process with Non-dominated Sorting Genetic Algorithm II and finite element. Examined the impact of composite molding process on compressive performance.
研究领域:
材料科学
·
制造工程
✓ 已验证
DOI
高影响因子
MACROMOLECULAR MATERIALS AND ENGINEERING
·
2022
·Vol. 307
·期 7
·2100941
·
IF 4.402
Long Ni,Yinfu Luo,Baowei Qiu,Liwei Yan,Huawei Zou,Shengtai Zhou,Mei Liang,Pengbo Liu
Lightweight flexible polyimide foams (PIFs) with different rigid-flexible molecular structure networks are prepared by microwave-assisted foaming of polyester ammonium salt (PEAS) precursor powders, followed by post curing process to complete final imidization. The optimum foaming temperatures of PEAS precursors range from 85 to 135 °C, and the melting rate of PEAS is adjusted to meet the volatile releasing rate to fabricate PIFs. Results show that PIFs with nearly fully open cell rate (99.99%), micron pore sizes (400–500 µm), and micro/nano multiscale structures exhibit excellent mechanical flexibility and elasticity. The prepared PIFs demonstrate exceptional thermal stability and heat resistance in both dynamic and static environments. The PIFs possess low thermal conductivity and superior thermal insulation properties that demonstrate potential applications in high-tech fields such as aerospace, marine use, and microelectronics among others.
研究领域:
材料科学
·
化学工程
·
航空航天材料
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Tao Zhou,Xiaoqing Zhang,Minglu Bu,Caihong Lei
Bio-based epoxy resins, which will replace petroleum-based ones, are gaining attention. In this work, three magnolol-based epoxy oligomers with varied structural unit rigidities (biphenyl, monophenyl, and aliphatic chains) were synthesized. Both the processability and the reactive activation of curing systems improved as structure unit rigidity decreased. “First-time curing resins” had only an epoxy-amine curing network, while “second-time curing resins” had dual curing networks. The structural unit rigidity regulated the thermal properties of first-time curing resins, which decreased with decreasing rigidity. However, P-MHQ-EP-n/DDM-1 had better mechanical properties than DGEBA/DDM, e.g., its impact strength (6.2 kJ/m 2 vs. 4.5 kJ/m 2 ) increased by 37.8%, indicating that moderate structural unit rigidity allows for good deformation and absorbs impact energy due to chain mobility. The second-time curing resins with increased crosslinking sites had better heat resistance (with a T g increase of over 71.6%), thermal stability, and char residue in comparison to the first-time curing resins. More impressively, P-MBP-EP-n/DDM-2 and P-MHQ-EP-n/DDM-2 obtain a LOI values greater than 39.0% and UL 94V-0 ratings because they have high-rigidity structural units and high crosslinking densities. In conclusion, well-balanced biobased epoxy resins could be made by regulating the structure-unit rigidity of epoxy oligomers and curing procedures.
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
·
2025
·
IF 9.8
Bin Du,Yinuo An,Liuqing Yang,Hanyi Li,Xianhua Huan,Yushun Zhao
This study presents the preparation of epoxy resin composites with fluorinated segment migration (FBEP) through the fluorination grafting modification of the epoxy resin matrix and optimization of the curing process to achieve effective regulation of surface resistivity. A stepwise curing procedure process was used to enhance the enrichment of fluorocarbon segments on the material surface, forming a fluorine-rich layer that regulates the distribution of traps. Experimental results show that as the pre-curing time is extended from 2 h to 10 h, the surface fluorine content increases from 3.8 wt% to 4.5 wt%, which leads to a decrease in surface resistivity from 4.243×10 15 to 1.346×10 15 Ω. Simultaneous measurements revealed a significant increase in the surface charge migration efficiency, with the surface potential decay amount after 22000 s increasing from 13.69% for FBEP-2 to 34.40% for FBEP-10. Moreover, the shallow charge trapping sites within the fluorine-rich layer effectively suppressed charge accumulation, causing the surface flashover voltage to rise from 21.13 to 27.70 kV, a 31.03% increase. The fluorinated segment directed migration strategy proposed in this study provides a novel solution for the coordinated enhancement of both surface resistivity and surface flashover voltage in epoxy resins.
研究领域:
材料科学
·
高分子科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2012
·Vol. 113
·期 2
·939-945
·
IF 1.604
Chen Yan,Yang Liting,Wu Jiahui,Ma Lijun,Finlow David E.,Lin Shaoquan,Song Keming
A series of new modified epoxy resin (EP) cured products were prepared from epoxidized soybean oil and commercial epoxy resin, with methyl nadic anhydride as curing agent and 1-methylimidazole as promoting agent. The thermal properties of the resins were characterized by DMA and TG; DSC was used to determine the curing process. Fourier transform infrared spectroscopy was utilized to investigate their molecular structures and scanning electron microscopy was used to observe the micro morphology of their impact fracture surfaces. Tensile and impact testing was employed to characterize the mechanical properties of the cured products. The combination of commercial EP with 20 wt% ESO resulted in a bioresin with the optimum set of properties: 130.5 °C T
g , 396.9 °C T
50 % , 74.89 MPa tensile strength, and 48.86 kJ m −2 impact resistance.
研究领域:
高分子材料
·
复合材料科学
·
生物基聚合物
·
材料化学
·
热固性树脂
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Guanyu Han,Yaqing Liu,Guizhe Zhao
As the frequency range and application scenarios of electromagnetic devices continue to expand and diversify, developing materials with both broad frequency response and excellent wide-angle absorbing performance has become increasingly important. However, research on the mechanisms and strategies for enhancing the wide-angle absorption performance of all-dielectric metamaterials is still limited. Furthermore, stable absorbing plate materials with consistent structural and electromagnetic properties are essential for metamaterial design. The commonly used functional particles often experience uncontrollable sedimentation, leading to significant and irregular changes in the structure and electromagnetic characteristics of composite materials. In this work, a layer-by-layer gel/integrated solidification (LG/IS) process is proposed, enabling the fabrication of a uniform composite plate. Based on this plate, a double-layer stepped metamaterial (DSMM) with cubic copper cores (CCC) embedded in each unit cell is designed and manufactured. The introduction of CCCs strengthens the internal electromagnetic field through mechanisms such as electromagnetic resonance and unit coupling, improving impedance matching and extending the absorption bandwidth to 11.20 GHz, a 10.89 % increase compared to ordinary DSMM. Additionally, embedding CCCs stabilizes the electromagnetic field at large incident angles, significantly enhancing wide-angle absorption performance. This work provides valuable theoretical guidance and technical support for the bandwidth expansion and optimization of wide-angle absorption in all-dielectric metamaterials.
研究领域:
电磁学
·
材料科学
·
微波技术
✓ 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）