Polymers
·
2024
·Vol. 16
·期 9
·1188
·
IF 4.7
Heming Li,Xinming Wang,Ziyang Ding,Weiguo Gao,Yan Liu,Ke Ma,Zhizhi Hu,Yongqi Wang
Polymer materials with a low dielectric constant and low dielectric loss have the potential to be applied to high-frequency signal transmissions, such as mobile phone antennas and millimeter wave radars. Two types of diamines, 4,4′-diamino-p-tetraphenyl (DPT) and crown ether diamine (CED), were prepared for ternary copolymerization with BPDA in this study. Cross-links with molecular chains were formed, increasing molecular chain distance by utilizing rings of CED. The MPI films exhibit a good thermal performance with the increase in CED addition, with Tg > 380 °C and CTE from −4 × 10−6K−1to 5 × 10−6K−1. The Young’s modulus can reach 8.6 GPa, and the tensile strength is above 200 MPa when 5% and 7% CED are introduced. These MPI films exhibit good mechanical performances. The dielectric constant of PI−10% film can go as low as 3.17. Meanwhile, the relationship between dielectric properties and molecular structure has been demonstrated by Molecular Simulation (MS). PI molecules are separated by low dielectric groups, resulting in a decrease in the dielectric constant.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 40
·e56025
·
IF 2.7
Qingbiao Yang,Xiangyu Mei,Shuaida Shi,Kun Peng,Xiaoming Qi,M. D. Zahidul Islam,Xinyan Yang,Yinsong Si,Yaqin Fu
Ultralow- k materials with promising comprehensive performance to meet the increasing requirements of high-frequency communication are highly desired. Here, a cross-linked porous polymer SiCOH, synthesized via simple sol–gel method, was used as the filler to prepare SiCOH/PI composite films by physically blending, which demonstrates ultralow dielectric constant at high frequency. Notably, only 2.5% of SiCOH in the composite can significantly reduce the dielectric constant of PI from 3.0 to an ultralow value of 1.7 in the 9.5–12.4 GHz, together with a low dielectric loss of 0.029. Additionally, the SiCOH/PI composite maintains a high tensile strength of 82.4 MPa and a tensile modulus of 1.82 GPa, which is comparable to pure PI film. While the glass transition temperature ( T g ) increases to 370°C and the linear expansion coefficient is reduced to 30.7 ppm/°C, both of which are superior to those of pure PI film. Moreover, by introducing the hydrophobic SiCOH into PI, the contact angle of the composite films increased to 92.0°–99.0°. This simple and low-cost method not only effectively lowers the dielectric constant of PI but also improves the thermal stability, mechanical properties, and hydrophobic ability, greatly boosts the practical application of PI in high-frequency communication in the future.
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Chun Liu,Mingkang Wang,Xin Zhao,Changpeng Yang,Ran Wei,Wentao Zeng,Feng Ding,Sizhao Zhang,Yongjun Lei
Polyimide aerogel (PIA) can enable to withstand the extreme conditions in a great measure due to their exceptional thermal stability and excellent mechanical toughness properties derived from the rigid-ring structures, which are rather promising alternatives in terms of high-performance thermal protection materials for aerospace field. However, PIA usually suffers from poor dimensional stability at high-temperature atmosphere, accordingly leading into the degradation of macroscopic features, eventually restricting their extreme-ambient applications. Here, an in situ skeleton encapsulation growth strategy is proposed to modulate aerogel networking skeleton construction pattern, namely forming the binary organic–inorganic nature skeletons originated from PIA nanoscale structures encapsulated with polymethylsilsesquioxane. The resulting aerogel demonstrates superior dimensional stability (linear shrinkage down to 1.11% even experiencing at 300 °C for 3000 s) despite facing high-temperature heat flux shock, suggesting an excellent high-temperature resistant ability depending upon encapsulated Si-O-phase-layer networking skeletons formation and intrinsic strong chemical bonds of polyimide chains. Further, the aerogels own the exceptional extreme-condition tolerance when subjected to thermal shock cycling (−196 °C—300 °C), and fantastic flame retardancy at 1200 °C. This approach to developing PIA broadens the applicability of high-performance PIA and holds significant potential for aerospace thermal protection, particularly in extreme conditions.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Lu Shen,Binbin Sun,Long Ni,Xiaoting Liao,Yinfu Luo,Shengtai Zhou,Huawei Zou
Nowadays, it becomes imperative to develop polyimide (PI) aerogels with excellent thermal insulation and mechanical performance to suit the demanding needs in high-tech sectors such as aerospace, electronics and fire protection among others. Herein, a series of PI aerogels with different dianhydride structures were prepared by sol–gel method, with 2,2′-dimethylbenzidine (DMBZ) being used as the diamine. The microstructure, mechanical properties, thermal stability, and thermal insulation properties of PI aerogels were regulated by changing the dianhydride structure. The compressive strength of PI aerogels at 10% strain was in the range of 0.04–1.60 MPa, and PI PMDA-DMBZ aerogel exhibited the best compressive strength among the studied systems. In addition, PI BPDA-DMBZ aerogel had an initial degradation temperature up to 510°C and thermal conductivity as low as 0.032 W/(m⋅K), demonstrating excellent thermal stability and insulation properties that can withstand harsh conditions.
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2025
·
IF 6.1
Chi Yan,Jialin Li,Yuhao Dai,ZhiJiang Lan,Haobo Wang,Hua Tong,Xiaojun Ye,Xiao Yuan,Cui Liu,Hongbo Li
Polyimide (PI), commonly used in space applications, is vulnerable to atomic oxygen (AO) erosion in low Earth orbit, causing performance degradation. Atomic layer deposition (ALD) of ultrathin films has great potential as AO protective coatings for aerospace materials. In this study, nanometer-thick plasma-enhanced atomic layer deposition (PEALD) SiO 2 films were deposited on in-situ oxygen plasma-activated PI surfaces. The nucleation and growth process of SiO 2 was systematically analyzed. A uniform and dense SiO 2 film was formed, providing limited resistance to AO erosion, but not sufficient for extreme environmental conditions. To further enhance AO resistance, we introduced thermal ALD-Al 2 O 3 interlayers within the same processing window and alternately deposited conformal, continuous Al 2 O 3 /SiO 2 nanolaminates on the PI surface. The Al 2 O 3 interlayer effectively reduced the film deposition roughness, forming a smoother, denser barrier layer and minimizing growth defects. This dense ALD-Al 2 O 3 /SiO 2 nanolaminate, with its inert Si-O-Al bonds, effectively prevents AO from penetrating the substrate, showing superior protection under long-term AO exposure. After AO irradiation, the surface remained smooth with no obvious defects or voids, effectively avoiding undercutting caused by AO. The synergistic effect of alumina and silica provides excellent AO protection while maintaining good optical transmittance.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Yuwei Chen,Yidong Liu,Yonggang Min
This study pioneers a molecular topology engineering strategy by incorporating a twisted diamine motif into polyimide (PI) backbones, achieving an unprecedented integration of thermal stability, mechanical robustness, and optoelectronic functionality that surpasses conventional high-performance PIs. Unlike traditional PIs constrained by performance trade-offs (e.g., compromised flexibility for thermal resistance or sacrificed bulk properties for functionalization), the modified PI demonstrates a breakthrough balance: thermal degradation temperature (T5%) exceeding 560 °C, glass transition temperature (Tg) of 380 °C, and tensile strength of 160–180 MPa. Crucially, it exhibits green fluorescence (505–515 nm) under 365/467 nm excitation─a previously unreported optical capability in PIs. Molecular dynamics/density functional theory (MD/DFT) simulations coupled with UV–vis and mechanical analyses reveal that the twisted conformation induces molecular orbital reorganization and optimized stress distribution, establishing a design framework for multifunctional PIs. In contrast to additive-dependent modification approaches, this topology-driven strategy enables intrinsic multifunctionality while maintaining compatibility with industrial polymerization processes, overcoming scalability challenges in functional PI production. The work redefines PI applications in aerospace composites, optoelectronic systems, and next-gen sensors under extreme conditions, while providing a paradigm for developing performance-integrated polymers through rational topological design.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Energy Storage Materials
·
2024
·
IF 18.9
Wenxia Sima,Yuxiang Mai,Potao Sun,Ming Yang,Tao Yuan,Binghao Chen,Yuhang Yang
Polyimide, endowed with high thermal resistance due to its aromatic structure, is considered a potential candidate for high-temperature polymer dielectrics. However, the strong electron delocalization in the aromatic structure causes significant leakage current during high-temperature electron transport, impairing energy storage performance. This contradictory relationship presents a bottleneck in enhancing the high-temperature energy storage performance of PI. In this work, inspired by fish migration influenced by vortices, we propose inducing electron displacement through fluorine-modified aromatic structures, constructing an internal electric field in PI to affect electron transport. This approach cleverly resolves the conflict between thermal resistance and current loss caused by the aromatic main chain in PI, achieving a synergistic enhancement of thermal resistance and high-temperature energy storage performance. Experimental results show significant improvements in both the high heat-resistant quality and high-temperature energy storage performance of PI. The glass transition temperature increased from 257.32 °C to 264.07 °C, and the leakage current density decreased from 7.1 × 10 –7 A/cm 2 to 2.8 × 10 –8 A/cm². Simultaneously, with a charge-discharge efficiency of approximately 90 %, the discharge energy density increased from 0.36 J/cm 3 to 5.22 J/cm 3 , an improvement of 1345.98 %. This strategy validates the potential of aromatic structures as the main chain for high-temperature energy storage polymers.
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Huaqing Li,Nan Tang,Jianing Cui,Haodong Yan,Shipeng Wen,Yan Shi,Weidong Wu
Fiber-reinforced rubber materials find extensive applications in tire manufacturing, hoses, conveyor belts, and various industrial sectors. Polyimide (PI) fibers offer superior fatigue resistance, tensile strength, modulus, and high-temperature durability compared to aramid fibers, positioning them as ideal substitutes in the belt layers of aircraft tire. To enhance the interfacial adhesion between polyimide fibers and rubber while minimizing the use of toxic and environmentally harmful materials, a novel eco-friendly carbon-reducing dipping system was devised. This system employs blocked diisocyanate and epoxy resin to activate PI fibers, and then uses a dipping solution, primarily composed of a blend of styrene–butadiene–vinylpyridine (VP) latex, lignin, tannic acid (TA), and glyoxal, to dip the fibers. This approach connects PI fibers and the rubber matrix through chemical bonds, thereby effectively enhancing the interfacial adhesion between the fibers and the rubber. The H pull-out force of the PI fiber cords treated by this system reached 179.6 N, with an average 180° peeling force of 14.7 N, and dynamic fatigue resistance exceeding 67,000 cycles, comparable to those achieved with the resorcinol-formaldehyde-latex (RFL) dipping system. These results indicate the efficacy of the developed system as a potential replacement for the RFL system. This research presents a sustainable and environmentally friendly approach to enhancing the interfacial adhesion of fiber-reinforced rubber composites, thereby contributing to the advancement of innovative high-performance fibers and biobased dipping system.
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Xingwang Lai,Shan Huang,Jialin Zhang,Xialei Lv,Fangfang Niu,Jinhui Li
Photosensitive Solder resist (SR) materials require a high glass transition temperature ( T g > 170 °C) and a coefficient of thermal expansion matching that of copper (CTE≈17 ppm/°C) to meet the demands of manufacturing processes and application reliability. However, the commonly used epoxy resin in SR materials exhibits insufficient mechanical and thermal properties, failing to meet these requirements adequately. To address this issue, alkali-soluble photosensitive poly (amic ester) (PAE) materials were synthesized. By grafting a low-temperature curing accelerator, 6-([1,1′-biphenyl]–4-yl)–4-chloroquinoline (NQL), onto the hydroxyl groups of the PAE, the resultant grafted PAE resin was blended with an alkali-soluble photosensitive modified epoxy resin (APE) to enhance the mechanical and thermal properties of the SR composite. Research indicates that due to the low-temperature curing effect and electrostatic interactions of NQL, SR-2 (with a 10% PAE addition) exhibits a T g of 183 °C and a CTE of 16 ppm/°C, while SR-3 (with a 30% PAE addition) achieves a T g of 204 °C and a CTE of 20 ppm/°C. Furthermore, with the PAE addition of 5%, the lithography quality of SR is enhanced, enabling SR-1 to achieve a pattern resolution of up to 40 μm. The modification method involving PSPI blending has been shown to enhance the thermal stability, dimensional stability, and lithographic performance of SR, indicating significant potential applications in solder resist materials.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhilin Chen,Jia Chen,Xianbo Hou,Liming Chen
The development of flexible and foldable aerogels for thermal protection in harsh environments has been a long-term challenge as high porosity and weak interface connection can result in typical brittleness. Herein, a remarkable polymerization-regulated strategy was proposed to prepare polyimide (PI) aerogel films with high flexibility and efficient thermal insulation in extreme temperatures by using a facile phase-separation (PS-PI films) method. The polymerization degree of monomers was innovatively used to regulate the flexibility and mechanical properties of PS-PI films by slightly regulating the proportion of monomers. The results showed that the PI aerogel film realized the transition from brittleness to high flexibility, and the tensile strength and fracture strain of PS-PI films were increased by 3 times (11.7 MPa) and 4 times (18.7 %), respectively. Besides, a finite element model was established to analyze the tensile deformation process, revealing the destruction mechanism of aerogel film. The prepared PS-PI film also exhibited robust mechanical properties and efficient thermal insulation properties at extreme temperatures (−130 to 300 °C). The developed PS-PI film possessed high flexibility and efficient thermal-insulated performance at extreme temperatures, which could be a potential candidate for thermal protection in aerospace, energy, and buildings.
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Zhongli Zhang,Zhensheng Wu,Shuai Zheng,Haitao Yang,Fuqiang Tian
Aromatic polyimide (PI) is widely used in aerospace, microelectronics, and transformer insulation due to its excellent performance and design flexibility. With the rapid development of the military industry, the insulation layer of Tesla transformer windings demands low dielectric, high heat resistance, high breakdown strength, and aging resistance. This paper studies the performance of polyimide insulation film based on theoretical calculation and experimental methods. We used molecular simulation technology and density functional theory (DFT) to study the microscopic electrical and optical properties of polyimide molecules with eight structures, which saved time for subsequent experimental design. Then, we studied ordinary polyimide film, fluorinated polyimide film, and polyimide film with mica filler using experimental methods. We also analyzed the dielectric, electrical, and ageing properties of polyimide composites and finally prepared polyimide composites with excellent comprehensive performance.
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Yang Zhang,Jing-Wen Wang,Ying-Jie Ma,Zi-Long Zhang
Thermally conductive polymeric composites with low dielectric constant are highly promising for the packaging materials in the field of modern communication. Therefore, the synergistic improvement of low dielectric constant and high thermal conductivity has become a current research hotspot. In this work, we propose a one-step alkylation of boron nitride nanosheet (BNNS) with ultrasonic stratification using 1-hexanol, and then hot press the films to make Alkyl-BNNSs orient in the fluorinated polyimide (f-PI). The resulting Alkyl-BNNS/f-PI composite successfully realizes the synergistic improvement of thermal property and dielectric properties, exhibiting a high heat conductivity coefficient of 2.36 Wm −1 K −1 with a filler content of 4.99 wt.%. Moreover, the permittivity and dielectric loss of the film are as low as 1.76 and 0.0065 at 1 MHz, respectively. This work provides a facile strategy for breaking the bottleneck of making polyimide composites simultaneously with high thermal conduction and low dielectric performance. Highlights The composite exhibits a high heat-conducting coefficient of 2.36 Wm −1 K −1 . Ultra-low dielectric constant of 1.76 was achieved by the modification of film. Excellent breakdown resistance and flexibility were endowed with the composites.
✓ 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）