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聚苯醚绝缘材料热氧老化动力学参数计算方法

中国电机工程学报 2024年第9期44卷 3399-3407,I0005页

作者：刘飞黄兴溢江平开上海市电气绝缘与热老化重点实验室(上海交通大学化学化工学院) 上海市闵行区200240

聚苯醚是新能源储能和5G通信等产业领域的重要材料。热重动力学参数计算是快速评定聚苯醚热寿命的关键。但热重分析常选用氮气气氛且升温速率较高,导致老化机理发生改变。为此,该文通过慢速升温和空气气氛下的热重实验模拟聚苯醚的实际... 详细信息

聚苯醚是新能源储能和5G通信等产业领域的重要材料。热重动力学参数计算是快速评定聚苯醚热寿命的关键。但热重分析常选用氮气气氛且升温速率较高,导致老化机理发生改变。为此,该文通过慢速升温和空气气氛下的热重实验模拟聚苯醚的实际老化过程。在多个升温速率对应失效温度区间内拟合温度积分数值解修正Doyle系数,对早期热氧降解阶段进行动力学分析、求取活化能,并推估该阶段反应机理函数以计算指前因子。结果表明,该方法求解活化能的精度较Flynn-Wall-Ozawa法和ASTM E1641-18法更高,且聚苯醚实际热氧老化可等效为遵循类幂律反应机理函数的单一反应,计算得到的指前因子比假定反应机理的标准方法更加可靠。上述工作为聚合物绝缘的热氧老化动力学参数计算提供了有效的技术方法。

关键词：聚苯醚慢速升温热重分析热氧老化动力学参数

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Rapid, high-efficient and scalable exfoliation of high-quality boron nitride nanosheets and their application in lithium-sulfur batteries

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Nano Research 2021年第7期14卷 2424-2431页

作者： Yu Chen Qi Kang pingkai Jiang Xingyi Huang Frontiers Science Center for Transformative Molecules Department of Polymer Science and EngineeringShanghai Key Laboratory of Electrical Insulation and Thermal AgeingState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

Boron nitride nanosheets(BNNSs)have gained significant attraction in energy and environment fields because of their two-dimensional(2.)nature,large band gap and high thermal/mechanical ***,the current low production efficiency of high-quality BNNSs is still a bottleneck limiting their ***,based on sonication-assisted liquid-phase exfoliation,we demonstrated a rapid,high-efficient and scalable production strategy of BNNSs and documented the effects of a spectrum of exfoliation factors(e.g.,ultrasonic condition,solvent and bulk material feeding)on the yield of BNNSs.A record of yield of 72.5%was achieved while the exfoliated BNNSs have few-layer and defect-free *** to the Lewis acid sites of the boron atoms,the BNNSs can interact with the polysulfide anions in liquid electrolyte and also can facilitate the uniform lithium deposition,which finally endow a lithium-sulfur(Li-S)battery with long *** work provides a facile and rapid strategy for large scale preparation of high-quality BNNSs,also contributes a long-life strategy for dendrite-free Li-S battery,opens new avenues of BNNSs in energy application.

关键词： boron nitride nanosheets cavitation sonication-assisted liquid-phase exfoliation(SALPE) modified separators lithium-sulfur batteries

A novel degradable injectable HLC-HPA hydrogel with antiinflammatory activity for biomedical materials:Preparation,characterization,in vivo and in vitro evaluation

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Science China(Technological Sciences) 2020年第11期63卷 2449-2463页

作者： GAO Shang QU LinLin ZHU ChenHui OUYANG pingkai FAN DaiDi Shaanxi Key Laboratory of Degradable Biomedical Materials School of Chemical EngineeringNorthwest UniversityXi’an 710069China Shaanxi R&D Center of Biomaterials and Fermentation Engineering School of Chemical EngineeringNorthwest UniversityXi’an 710069China Biotech&Biomed Research Institute Northwest UniversityXi’an 710069China College of Biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjing 211816China

In situ injectable hydrogels,which have great potential in tissue engineering,are characterized by simple preparation,minimal invasiveness and adaptation to complex ***,injectable hydrogels have higher requirements for biocompatibility and safety due to their use in vivo ***,in this study,a human-like collagen(HLC)-based in situ gel-forming injectable HLC-HPA hydrogel was synthesized by combining the amino group of HLC with the carboxyl group of HPA activated using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride(EDC)and N-hydroxysuccinimide(NHS),followed by crosslinking by horseradish peroxidase(HRP)and H_2._2.and used as scaffold material for tissue *** hydrogel stiffness,gel time and biodegradation rate could be easily and independently adjusted by varying the H_2._2.and HRP *** electron microscope(SEM)clarified the homogeneous porous and interconnected internal structures of the *** vitro cell viability and in vivo degradation experiments confirmed that the HLC-HPA hydrogel had good biodegradability and excellent ***,in cultured macrophages,the HLC-HPA hydrogel showed anti-inflammatory activity by reducing the amount of the pro-inflammatory cytokines tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)and increasing the secretion of the anti-inflammatory cytokine interleukin-10(IL-10)induced by lipopolysaccharide(LPS).Meanwhile,in animal experiments,HLC-HPA hydrogels exhibit excellent biocompatibility and have properties of hemostasis and reduction of inflammatory ***,the HLC-HPA hydrogel prepared in this study has great potential for development for use in the biomedical field.

关键词： injectable hydrogels human-like collagen biocompatibility anti-inflammation hemostasis

The influence of the NCO/OH ratio and the 1,6-hexanediol/ dimethylol propionic acid molar ratio on the properties of waterborne polyurethane dispersions based on 1,5-pentamethylene diisocyanate

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Frontiers of Chemical Science and Engineering 2019年第1期13卷 80-89页

作者： Jiao Feng Qiuhao Lu Weimin Tan Kequan Chen pingkai Ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University Nanjing 211816 China National Engineering Research Center for Coatings CNOOC Changzhou Paint and Coatings Industry Research Institute Co. Ltd. Changzhou 213016 China

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5-pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transfonn infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffiraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH = 3, HDO/DMPA = 2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU.

关键词： 1,5-pentamethylene diisocyanate polyurethane water based

Epoxy thermoset resins with high pristine thermal conductivity

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High Voltage 2017年第3期2卷 139-146页

作者： Ying Lin Xingyi Huang Jin Chen pingkai Jiang Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China

Heat dissipation becomes a critical problem because of the miniaturisation and the increase of power density in electronic devices and electric equipment,which calls for electrical insulating materials with high thermal management *** thermosets have been widely used as electrical insulating materials,but suffer from their low thermal *** study reviewed the research progress on the development of epoxy thermosets with high pristine thermal ***,the thermal conduction mechanism of polymers was briefly ***,the approaches used to enhance the thermal conductivity of epoxy thermosets were summarised,which mainly dealt with the formation of microscopically anisotropic but macroscopically isotropic structure in the epoxy ***,the applications of high thermal conductivity epoxy thermoset resins were ***,the review provided the existing challenges and the future directions for the development of epoxy thermosets with high pristine thermal conductivity.

关键词： thermal conductivity resins

Dielectric phenomena and electrical energy storage of poly(vinylidene fluoride) based high-k polymers

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Chinese Chemical Letters 2017年第11期28卷 2027-2035页

作者： Yingke Zhu pingkai Jiang Zhicheng Zhang Xingyi Huang Department of Polymer Science and Engineering Shanghai Key Laboratory of Electrical Insulation and Thermal Aging Shanghai Jiao Tong University Shanghai 200240 China Department of Applied Chemistry School of Science Xi'an Jiaotong University Xi'an 710049 China

Polymeric dielectrics have wide range of applications in the field of electrical energy storage because of their light weight and easy processing. However, the state-of-the-art polymer dielectrics, such as biaxially orientated polypropylene, could not meet the demand of minimization of electronic devices because of its low energy density. Recently, poly（vinylidene fluoride）（PVDF） based ferroelectric polymers have attracted considerable interests for energy storage applications because of their high permittivity and high breakdown strength. Unfortunately, the high dielectric loss and/or high remnant polarization of PVDF-based polymers seriously limits their practical applications for electrical energy storage. Since the discovery of relaxor ferroelectric behavior was firstly reported in irradiated poly（vinylidene fluoride- trifluoroethylene）（P（VDF-TrFE）） copolyrner, many strategies have been developed to enhanced the electrical energy storage capability, including copolymerization, grafting, blending and fabricating of multilayer How these methods affect the polymorphs, crystallinity, crystal size of PVDF-based polymers and the connection between these microstructures and their corresponding energy storage properties are discussed in detail.

关键词： PVDF Ferroelectric polymer Copolymerization Grafting Energy storage Dielectric constant Dielectric loss Breakdown strength

Recent advance of chemoenzymatic catalysis for the synthesis of chemicals: Scope and challenge

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Chinese Journal of Chemical Engineering 2021年第2期34卷 146-167页

作者： Mengjiao Xu Zhuotao Tan Chenjie Zhu Wei Zhuang Hanjie Ying pingkai Ouyang College of Biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjing 211816China

Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of *** chemoenzymatic methods can not only save resource,cost,and operating time but also reduce the number of reaction steps,and avoid separating unstable intermediates,leading to the generation of more products under greener circumstances and thereby playing an indispensable role in the fields of medicine,materials and fine *** incompatible challenges between chemocatalyst and biocatalyst remain,strategies such as biphasic system,artificial metalloenzymes,immobilization or supramolecular host,and protein engineering have been designed to overcome these *** this review,chemoenzymatic catalysis according to different chemocatalysis types was classifiably described,and in particular,the classic dynamic kinetic resolutions(DKR)and cofactor regeneration were ***,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.

关键词： Chemoenzymatic Dynamic kinetic resolution Cofactor regeneration Biocatalysis Chemocatalysis

Wet-resilient graphene aerogel for thermal conductivity enhancement in polymer nanocomposites

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Journal of Materials Science & Technology 2021年第24期83卷 219-227页

作者： Ying Lin Jin chen Shian Dong Guangning Wu pingkai Jiang Xingyi Huang Department of Polymer Science and Engineering Shanghai Key Lab of Electrical Insulation and Thermal AgeingThe State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China School of Electrical Engineering Southwest Jiaotong UniversityChengdu 610031China

Three-dimensional(3 D)graphene-based aerogels have significant potential for adsorption,sensors,and thermal management ***,their practical applications are limited by their disorganized structure and ultra-low resilience after *** methods can realize a well-aligned structure,however,they involve high costs and complex ***,a 3 D graphene hybrid aerogel with an anisotropic open-cell and well-oriented structure is realized by unidirectional freeze casting,which combines the‘soft’(*** oxide,Tween-80)and‘hard’(*** assembly)components to realize full recovery after flattening.A graphene aerogel annealed at a moderate temperature(2.0℃)can possess superhydrophilicity and outstanding wet-resilience properties,including after being pressed under40 ***,the graphene aerogel annealed at a high temperature of 1500℃exhibits excellent thermal conductivity enhancement efficiency in polydimethylsiloxane(PDMS).The resultant nanocomposites clearly demonstrate anisotropic thermal conductivity and promising applications as thermal interface *** strategy offers new insights into the design and fabrication of 3 D multifunctional graphene aerogels.

关键词： Graphene aerogel Unidirectional freeze casting Interface self-assembly Wet resilience Thermal conductivity enhancement

The production of enantiopure D-lysine from L-lysine by a two-strain coupled system

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2832-2836页

作者： Sheng Xu Xiaolu Lu Xin Wang Zhen Gao Kequan Chen pingkai Ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211816China

The microbial production of D-lysine to replace chemical approach has gained great interest with the rising concerns over the ***,we employed recombinant *** strain BL2.-LYR with lysine racemase and strain BL-2.A-RB-YB with L-lysine monooxygenase and 5-aminovaleramide amidohydrolase to establish a two-strain coupling whole-cell bioconversion system for D-lysine production from *** improve the optical purity of D-lysine,the optimal reaction condition for resolution of DL-lysine after the racemization was *** specificity of BL-2.A-RB-YB for L^-lysine and the effects of reaction condition on bioconversion efficiency of whole-cell were accordingly *** the optimal condition,a maximum 53.5 g·L^-1 D-lysine and 48.2.g·L^-15-AVA were obtained with yield of 47.4%and 42.3%,respectively,by the microbial racemization and asymmetric degradation *** final D-lysine enantiomeric excess was over 99%.Meanwhile,a valuable compound 5-aminovaleric acid was synthesized with the production of D-lysine,indicating the economic feasibility of the two-strain coupling system.

关键词： _D-Lysine Microbial resolution Two-strain coupling system