POLYMER COMPOSITES
·
2022
·Vol. 44
·期 2
·886-896
·
IF 3.531
Jialin Zhang,Yuying Sui,Jinhui Li,Liang Shan,Fangfang Niu,Guoping Zhang,Rong Sun
One challenge in the high-performance dielectric material of polyimide (PI) is to obtain the excellent comprehensive properties at low curing temperature for advanced IC package. In this work, 6-aminoquinoline (AQL) is introduced through covalent bonds for end capping to obtain a low-temperature curable PI at first. The results demonstrate that with very limited introduce (2.76%) of AQL, the imidization index could reach as high as 1.01 at 200°C. Then, fluorinated nano carbon (FC) is further introduced resulting in the fluorinated nano carbon/polyimide (FCPI) composites, which effectively reduces the dielectric constant (1 wt%, 2.75 @ 1 MHz). Besides, the as-prepared FCPIs also possess excellent thermal property of which FCPI-0.3 exhibited the 5% weight loss temperature of 540°C and the glass transition temperature is also as high as 385°C. Furthermore, the tensile strength of the film is 127 MPa, the elongation at break is around 15.82%, and the Youngs' modulus is about 3.10 GPa proving the superior mechanical property. As a result, the successful preparation of the FCPI nanocomposites not only possess low-temperature curing and low-dielectric performance but also exhibit excellent thermal and mechanical properties, which shows a wide range of application prospects in the field of microelectronics for the advanced electronic package.
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Song Zuo,Maohua Li,Shaoxiong Xie,Jinpeng Luo,Lexiang Xu,Yan Shi,Ningxiang Lan,Lang Zhou,Jinhong Yu,Xiaomin Li,Chuanqiang Yin
Boron nitride nanosheet (BNNS) is widely used in electronic thermal management due to its excellent planar thermal conductivity and insulating properties. However, it is challenging to improve the out-of-plane thermal conductivity of BNNS-doped composites due to the anisotropy of the thermal conductivity of BNNS. Therefore, the BNNS in the matrix must be oriented to obtain composites with high out-of-plane thermal conductivity. In this study, BNNS powders with directional structures were synthesized directly using sodium chloride templates. The as-obtained BNNS powders have a unique hollow cube-like structure with an ultra-low density of 2.67 × 10 −2 g/cm 3 and nearly 8 times the volume of the same mass of two-dimensional (2D) BNNS, making it easy to form the out-of-plane thermal conductivity paths in the polymer matrix . In addition, the high out-of-plane thermal conductivity of 4.93 W m −1 K −1 at 23.3 wt% loadings was obtained by doping it into a polyimide (PI) matrix. This value is 9.7 times higher than that of 2D BNNS-doped PI at the same loadings, 17.6 times higher than pure PI, and 6.1 times higher than the thermally conductive PI film sold by DuPont. Therefore, the prepared composite film has great potential for application in electronic thermal management.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Pengtu Zhang,Xiaoyun Liu,Peiyuan Zuo,Puke Mi,Qixin Zhuang
With the development of renewable energy resources, polymer-based dielectric materials, as key components in energy storage devices with optimized dielectric property, high-temperature stability, and good processibility, are highly demanded. In this study, p-phenylenediamine (PPD)-modified and l-ascorbic acid (LAA)-reduced graphene oxide (NH2-CRG) nanosheets with significant chemical functionalization and significantly improved dispersity were prepared. Also, polyimide was chosen to be the polymer matrix due to its high-temperature resistance, chemical inertness, and excellent mechanical property. By incorporating NH2-CRG into the PI polymer matrix via in situ polymerization, 0.8 wt % NH2-CRG/PI composite material with a dielectric constant as high as 839 and a breakdown strength of 80 kV·mm–1 was obtained. Meanwhile, the 5 wt % weight loss temperature of 0.8 wt % NH2-CRG/PI witnessed a 17.6 °C increase compared to pure PI. This work provided a promising strategy to prepare graphene-based materials for high-dielectric applications and a realizable process of fabricating polymer-based dielectric composite materials.
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Long Ni,Yinfu Luo,Guanchun Wang,Liwei Yan,Yunfei Gao,Haichao Meng,Shaoyu Qiu,Mei Liang,Shengtai Zhou,Huawei Zou
Mechanically robust lightweight polyimide foams (PIFs) with anisotropic pore structures were successfully prepared using microwave-assisted foaming and thermal imidization. The foaming behavior of polyester ammonium salt powders was assessed by rheological and TG-FTIR analyses. The release of volatile gases (e.g., H2O, tetrahydrofuran, and methanol) between 85 and 150 °C led to the directional growth of foam pores during microwave treatment, which was critical for endowing PIFs with excellent thermal insulation and mechanical properties. The use of 4,4′-diaminobenzanilide (DABA) as the copolymerization reagent enhanced the compressive strength@50% strain (92.25 kPa) in the vertical direction (i.e., pore growth direction) and high elasticity in the horizontal direction (compression response rate reached up to 98.95%). The PIFs demonstrated exceptional thermal stability under both inert and air atmospheres. Meanwhile, PIFs exhibited anisotropic thermal insulation behavior, exhibiting a thermal conductivity as low as 0.0264 W/(m·K) in the horizontal direction (i.e., perpendicular to the pore growth direction), which was ideal for thermal insulation purpose under high temperatures. Therefore, PIFs with excellent mechanical performance and exceptional heat resistance and thermal insulation properties were facilely prepared, which show promising applications in high-end engineering sectors.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Xinfu Zhao,Yihao Nie,Xibin Yi,Shimo Yu,Jing Zhang,Xiaochan Liu,Zhipeng Yuan,Sijia Liu,Jian Zhang,Guoliang Dou,Mengdi Wang
Design of efficient CO 2 adsorbent is an effective way to capture CO 2 . Bamboo-derived activated carbon is a promising CO 2 adsorbent. Inspired by this, carbonized unidirectional polyimide (CUPI) aerogels were newly designed by the ice templating method using directional freezing technology. The pore property of CUPI aerogel can be tuned by changing the solidification velocity, and a series of CUPI aerogels were designed to explore the CO 2 capture performance in view of pore morphology/topology. As a result, the obtained CUPI-8 exhibits higher CO 2 adsorption capacity compared to carbonized polyimide aerogels due to the synergistic effect of micropores and lamellar pores. Specially, the CO 2 adsorption capacity over CUPI-8 can be up to 5.75 mmol/g at 20 bar and 298 K. Furthermore, the adsorption isotherm of CUPI-8 still shows an upward trend even nearly 20 bar. The isosteric adsorption heat (Q st ) value of CUPI-8 is nearly in the ideal scope of 30–50 kJ mol −1 . The efficient CO 2 adsorption performance and good chemical stability of CUPI aerogel makes it a promising absorbent for practical application. This work provides a new opportunity for researching the effect of pore morphology/topology and the synergistic effect of hierarchical pores on CO 2 capture.
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Zicheng Fan,Insub Noh,Changlong Zhuang,Qingqing Liu,Yanbin Wang,Hyung Do Kim,Meng Yue,Hideo Ohkita,Biaobing Wang
With the rapid development and application of 5G technology, design and fabrication of lightweight polymer materials with excellent flame retardancy, low dielectric constant, and high thermal insulation is a worthy but great challenge. In this study, a polar polyimide (PI) contain amide group was designed and incorporated into epoxy resin (EP) to fabricate multifunctional materials combing a small molecule named phenoxycycloposphazene (HPCTP). Due to the synergistic effect of PI and HPCTP in flame retardant, EP blend passed UL-94 V-0 rating only needing 3 wt% PI and 1 wt% HPCTP, meanwhile the limited oxygen index (LOI) obviously increased from 23.8% to 35.0%. More importantly, the dielectric constant obviously decreased at a wide range from 10 −1 to 10 7 Hz and the thermal conductivity also reduced by more than 45% from 0.236 to 0.127 W m −1 K −1 . Due to the good compatibility and reactivity between PI and EP, PI was uniformly dispersed and connected EP to construct intimate 3D interpenetrating polymer network, and thus the tensile and flexural properties were slightly enhanced. Moreover, combustion parameters, including peak heat release rate (PHRR), total heat release (THR), smoke produce rate (SPR) and total smoke production (TSP), all indicated that EP composites significantly reduced fire risk. Overall, this study offers a promising strategy to fabricate flame retardant EP composites with outstanding comprehensive performances.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2022
·
IF 4.855
Jianwei Li,Jun Lin,Yugen Wang,Wei Chu,Fei Liu,Bin Wang
High-performance and light-weight polymer foams with ultralow dielectric constant, good thermal stability, and high mechanical strength are greatly needed in aviation and aerospace fields. In this work, cross-linked and rigid polyimide (PI) composite foams were fabricated based on norbornene terminated polyamide ester oligomer precursor powders via thermal foaming method. The obtained PI composite foams exhibit outstanding characteristics of light weight (90–130 kg·m–3) and high mechanical strength. When the glass fiber (GF) loading was 10 wt %, the compressive strength and modulus of PI/GF composite foams reached 1.7 and 49.6 MPa, respectively. Moreover, the PI foams exhibit remarkable thermal stability and fire-resistant property (LOI > 42%). The thermal conductivity of the prepared PI foams was measured to be in the range of 0.039–0.052 W·m–1·K–1 at room temperature. In addition, the PI composite foams present ultralow dielectric characteristic (tan δ = 0.006–0.008 at 10 GHz) and prominent wave-transparent performance (>95%) in the X band (8.2–12.4 GHz). These beneficial integrated properties enable the resultant PI composite foams to be attractive candidates for applications in aviation and aerospace fields.
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2022
·Vol. 43
·期 10
·7200-7210
·
IF 3.531
Feng Gao,Jiahao Shi,Xiaorui Zhang,Xuan Wang,Ling Weng,Xue Sun,Lida Yu,Chenhao Li
Bismaleimide resin (BMI) is a thermosetting resin with excellent properties. However, due to its poor toughness as a cured product, this paper uses hyperbranched polyimide (HBPI) and nano-SiO 2 in a synergistic manner to improve the performance of BMI. Isophorone diisocyanated tripolymer (IPDI trimer) and methyl nadic anhydride (MNA) were used to synthesize HBPI, and then we investigated the effect of the synergistic modification on the mechanical and thermal properties and the modification mechanism of HBPI and nano-SiO 2 . The experiments showed that the most significant improvements were achieved at the addition of 40 and 3 wt% of HBPI and nano-SiO 2 respectively, with the impact strength of the materials increasing by 97.2%, fracture toughness indexes G IC and K IC increased by 36.7% and 34.6% respectively and glass transition temperature ( T g ) was reduced. The SEM results showed that the nanoparticles were uniformly dispersed and further validated the synergistic modification mechanism.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Xiaogang Li,Kefan Liu,Yue Yan,Junfeng Yu,Nanxi Dong,Bingxue Liu,Guofeng Tian,Shengli Qi,Dezhen Wu
Separators are applied to segregate cathode and anode, and provide ion transport channels in lithium-ion batteries (LIBs). Nevertheless, present commercial polyolefin separators represent high thermal shrinkage and inferior electrolyte wettability , seriously limiting wider development of LIBs. In this work, we prepared zirconia (ZrO 2 ) nanolayer encapsulated polyimide (PI) nanofiber compound separator through in-situ polar adsorption and hydrolysis strategy. The obtained PI/ZrO 2 compound separator has superior thermal stability, electrolyte wettability and flame retardance in comparison with polypropylene (PP) separator. The shrinkage ratio of prepared PI/ZrO 2 compound separator is 0 even at 300 °C, while the PP separator significantly shrank at 160 °C. Furthermore, the ionic conductivity of PI/ZrO 2 separator reaches up to 1.32 mS cm −1 , far higher than 0.34 mS cm −1 of PP separator. Besides, the coin batteries of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811)/electrolyte-separator/lithium (Li) assembled with PI/ZrO 2 compound separator exhibit enhanced rate performance, high discharge capacity retention rate of 88.3% after 100 cycles at 1C and excellent battery safety performance even at 140 °C. Thus, combined with its advantages, such as preparation, thermostability, electrolyte wettability, electrochemical property and safety, the PI/ZrO 2 compound separator exhibits promising prospect in the application of commercial LIBs.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
He Huang,Can Wu,Shiqi Wu,Ruiqun Pan,Lianhua Yin,Xiangyu Jin,Yiwu Pan,Hebing Wang,Xiaojie Yan,Changqing Hong,Wenbo Han,Xinghong Zhang
Soft and thermostable materials are crucial to applications in the fields of aerospace, wearable materials, and artificial intelligence (AI) in harsh environments. However, decided by the molecular structures, most soft materials are easy to pyrolyze at 100–200 °C, hindering developments in the critical technologies for such applications. In this work, through a rational “slice/sphere” dual-morphology microstructure design, a hydrogen-bonded polyimide/silicone aerogel is obtained with a two-step-gelling process. As rationally discussed with evidence, the recoverable “air compression” and the “silicone sphere deformation” contribute to the superflexibility, with the low elastic modulus (0.155 kPa), high cyclic compressive strain (90%), and good fatigue-resistance (600 cycles at 50% strain). Additionally, the structure and components together endow the composite with light weight (0.14–0.16 g cm −3 ), low bulk shrinkage (less than5%), superhydrophobicity (water contact angle of 150.1°), prominent thermostability (weight remains 90% at 474 °C), promising thermal insulating performance below 600 °C, and stable sensing ability at 300 °C. The efficient thermal insulation, sensible pizeopermittivity and endurance in a wide temperature window (−196–400 °C) make it feasible for conformal thermal protection and strain sensors for aerospace, and AI applications under harsh conditions.
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2022
·Vol. 24
·期 10
·1866-1876
·
IF 3.756
Shuai Han,Cui Liu,Nian Li,Shudong Zhang,Yanping Song,Liqing Chen,Min Xi,Xinling Yu,Wenbo Wang,Mingguang Kong,Zhenyang Wang
Heteroatom doping of graphene electrodes is a valid strategy to enhance their capacitive performance. This work demonstrates a facile and expandable methodology for the in situ fabrication of nitrogen-doped laser-induced graphene (N-LIG) by the precursor composite approach in conjunction with laser induction technology. Melamine (C3H6N6) with high N content was compounded with polyimide to form a composite film, on which N-LIG was synthesized by one-step in situ laser pyrolysis. In this process, N elements from melamine were successfully doped into the graphene structure. As a result, the optimal N-LIG electrode exhibited a desirable specific areal capacitance (CA) of 56.3 mF cm−2 at 0.4 mA cm−2 in 1 M H2SO4 aqueous electrolyte, which was 7.2 times that of the pristine undoped LIG electrode. Besides, the N-LIG electrode obtained on the composite film kept good flexibility, which laid a foundation for the industrial roll to roll production of N-LIG. Furthermore, the N-LIG-based all-solid-state micro-supercapacitor (MSC) revealed a high CA of up to 35.20 mF cm−2 at 0.05 mA cm−2 and an impressive cyclic stability of 85.5% after 10 000 cycles. This presented strategy possesses the advantages of environmental protection, economy and convenience, and exhibits a broad application prospect in flexible wearable electronics and energy storage devices.
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2021
·Vol. 6
·期 4
·482-490
·
IF 6.482
Zhou Xiao,Jing Che,Huaxin Li,Xian Yue,Xianbo Yu,Fenglei Sun,Chao Xue,Junhui Xiang
Polyimide (PI) aerogels with high thermal stability and low thermal conductivity can be used in the field of high-temperature insulation. However, the superhydrophilicity of the PI aerogel means the structure of the aerogel is easily damaged by water and then the thermal insulation performance is obviously reduced. In addition, the poor elasticity of PI aerogels limits their areas of application where more flexible materials are required. Herein, the authors synthesized a silica/polyimide (SiO2/PI) composite aerogel with both superhydrophobicity and elasticity through the strategy of “double confinement growth”. In this “double confinement” process, a “co-sol” system of silica/polyamic acid salt (SiO2/PAAs) was directionally frozen instead of a traditional “co-gel” system preparation. The freely movable SiO2 and PI were aligned under the confinement of ice crystals to form a regular honeycomb structure. Then it underwent freeze-drying and imidization to form the final SiO2/PI aerogel. Due to the introduction of a large amount of methyl groups, the aerogel has excellent superhydrophobicity, where the water contact angle reaches 153.1°. Water droplets can roll freely on the surface of the aerogel, and this lotus effect can prevent the structure of the aerogel from being damaged by water. Meanwhile, the regular honeycomb structure provides good elasticity for the material. The volume recovery rate reached 99.2% after 80% strain, and the volume recovery rate was 96.22% after 50% strain in 50 cycles. Moreover, the compression does not reduce the thermal conductivity of the material (0.0374 w m−1 K−1). This shows that the synthesized aerogel material can still maintain its high-efficiency heat insulation performance under repeated compression. The unique high thermal decomposition temperature of PI and SiO2 ensures the stability of the aerogel in a high-temperature environment, and at the same time, its non-combustible and non-melting characteristics can effectively prevent the spread of and damage by flames. This novel elastic and superhydrophobic aerogel is an ideal choice for high-temperature insulation materials, especially for flexible insulation materials such as high-temperature insulation cloth.
✓ 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）