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Effect of matrix resin components on properties of the semi-conductive shielding material for high-voltage cable

High Voltage 2024年第2期9卷 419-428页

作者： Guochang Li Tianyao Liu Xiaolong Chen Yanhui Wei Chuncheng Hao Shengtao Li Institute of Advanced Electrical Materials Qingdao University of Science and TechnologyQingdaoChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina

The semi-conductive shielding layer is an important part of the high-voltage cable,playing a role in uniform electric field and reducing the air gap at the interface.The overall performance of the cable is affected by the semi-conductive shielding layer with different base resin composition.The matrix resins of ethylene-vinyl acetate(EVA),ethylene-ethyl acrylate(EEA)and ethylene-butyl acrylate(EBA)were used to prepare the semi-conductive shielding materials of CB/EVA,CB/EEA and CB/EBA.The influences of different matrix resins on the chemical,electrical,thermal and mechanical properties of the shielding materials were investigated.The results show that CB has the best dispersion in EBA resin and the worst dispersion in EEA resin.The temperature in-flection points of CB/EVA,CB/EEA and CB/EBA shielding materials are 90°C,100°C and 110°C,respectively,and the CB/EBA shielding material has the lowest resistivity and the weakest positive temperature coefficient effect at room temperature.The thermal conductivity of all three matrix resins is smaller than that of the shielding material,the thermal conductivity of CB/EVA and CB/EBA shielding materials show a slow increase with temperature,and the CB/EEA shielding material is the least affected by the tem-perature.The mechanical properties of the three matrix resins and the three shielding materials are EBA>EVA>EEA,among them the stress of CB/EBA shielding material is 31.0 MPa and the strain is 570%.This work has important reference significance for the selection of shielding layer matrix resin and material formulation in engineering applications.

关键词： temperature. resin resins

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Study of asphaltene reaggregation in toluene/heptane mixture by dynamic and static light scattering

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Petroleum Research 2024年第1期9卷 48-54页

作者： Vladimir N.Kuryakov Oil and Gas Research Institute of RAS(OGRI RAS) Gubkina Str.3119333MoscowRussian Federation

This paper presents the study of the effect of multiple ultrasonic impacts on submicron asphaltene aggregates in a toluene/heptane solution,conducted with dynamic light scattering technique.The objects of the study were four samples of asphaltenes obtained from four different oils.For all samples,the change in the average size of the asphaltene submicron aggregates with time was measured after the addition of a precipitant(heptane)to a solution of asphaltenes in toluene at an amount above the threshold concentration.Asphaltene aggregates formed in solution after the addition of the precipitant and were subjected to ultrasonic treatment,which led to the destruction of the asphaltene aggregates.Aggregation of destroyed asphaltenes was observed.The kinetics of this aggregation were similar to the kinetics of aggregation of asphaltenes after the addition of a precipitant.Multiple iterations of asphaltene aggregate destruction in the sample led to a significant change in the kinetics of aggregation:the growth of aggregates slowed and stabilized at a size of approximately 200 nm and 30 nm for the different studied samples.

关键词： Asphaltenes Aggregation Sonication Dynamic light scattering Re-aggregation Colloidal stability resins

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Thermal ageing of soft and hard epoxy resins

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High Voltage 2023年第1期8卷 12-20页

作者： Yoshimichi Ohki Naoshi Hirai Research Institute for Materials Science and Technology Waseda UniversityShinjuku-kuTokyoJapan

Two kinds of epoxy resin,a soft one with rubber-based additives and an ordinary hard one,are used as electrical insulators and airtight sealants in electrical penetrations in nuclear power plants(NPPs).Knowing how they behave under adverse environments is important for the safe operation of NPPs.In this regard,we gave artificial thermal ageing treatment to the two resins by heating them in air at various temperatures.The resins were then subjected to mechanical,thermal,and dielectric tests.As a result,it has become clear that the soft epoxy resin becomes hard,while its permittivity and loss factor decrease as the heating becomes longer.The glass transition tends to occur at a high temperature in the soft epoxy resin when it was heated.With these changes,the soft resin tends to exhibit similar behaviour in various properties to that of the unaged hard one.On the other hand,the hard one is hardly affected by the simulated thermal ageing.Therefore,both resins can be useable in NPPs.

关键词： resin resins heated

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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 capability.Epoxy thermosets have been widely used as electrical insulating materials,but suffer from their low thermal conductivity.This study reviewed the research progress on the development of epoxy thermosets with high pristine thermal conductivity.First,the thermal conduction mechanism of polymers was briefly introduced.Second,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 thermosets.Third,the applications of high thermal conductivity epoxy thermoset resins were reviewed.Finally,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

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Hydrolysis Activities of resins of Complexes Made from Polysaccharides and Ce^(4+)

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Journal of Rare Earths 2006年第Z2期24卷 125-129页

作者：于丽娜汪东风李海燕苏琳王家林 College of Food Science and Technology Ocean University of China Tsingtao Brewery Company Limited

resins of complexes made from agarose-Ce4+ (RCA-Ce) and chitosan-Ce4+ (RCC-Ce) were prepared. Hydrolysis rates of methamidophos, omethoate and chlorpyrifos treated by RCA-Ce were 32.39%, 27.12% and 46.62%, respectively, those of chlorpyrifos and methamidophos in mung bean sprout juice 38.28% and 35.45%, and that of chlorpyrifos in tea extract 59.76%. Hydrolysis rates of protein in tea extract treated by RCA-Ce increased by 86.46%. RCC-Ce could be employed in the apple juice production. The contents of methamidophos and parathion-methyl in the juice treated by RCC-Ce decreased 58.76% and 71.92%. Furthermore, RCC-Ce was used to clarification for beer by the ways of a column. RCC-Ce could hydrolyze sensitive protein and increase contents of free amino acid in the beer. Therefore, the beer treated by RCC-Ce could stay oxidation and aging procedure due to some metal ions being absorbed by RCC-Ce.

关键词： resins polysaccharides cerium hydrolyze protein organophosphorous pesticides rare earths

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Dielectric behaviours of bio-derived epoxy resins from cashew nutshell liquid

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High Voltage 2021年第2期6卷 255-263页

作者： Mulan Mu Alun Vaughan Department of Electronics and Computer Science Tony Davies High Voltage LaboratoryUniversity of SouthamptonSouthamptonUK Novel Polymer Technology Section TWI LtdCambridgeUK

In this study,four commercially available bio-derived epoxy systems(extracted from cashew nutshell liquid)were prepared and characterised.The glass transition temperature(Tg),dielectric spectroscopy,DC conductivity and breakdown properties of these epoxy resins were studied.Differential scanning calorimetry(DSC)demonstrated that the T_(g) of the investigated systems ranged from 67 to 122°C.The DC conductivity was very low(<10^(-16) S cm^(-1))and comparable to the conventional dielectrics at room temperature(RT).However,all systems showed a strong temperature dependence of the electrical conductivity and exhibited sharp increase around their respective T_(g).Arrhenius analysis led to activation energy,E_(a),values around 1 eV;higher E_(a) values were observed in systems with a lower T_(g).Dielectric spectroscopy revealed a flat and low response at temperature below T_(g).However,both the real and imaginary permittivity increased with decreasing frequency at mid to low frequencies as the temperatures approached T_(g).The variations of AC breakdown strength of all samples were not statistically significant,but the DC breakdown strength of sample 2503Aþ2002B was higher than the others,which might be due to reduced charge transport in this system.The results indicate that novel bio-derived epoxy systems from renewable sources are potential alternatives for traditional petroleum-based epoxy systems in certain insulation applications.

关键词： conductivity resins liquid

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Rheological behavior of novel polyamide 6/silica nanocomposites containing epoxy resins

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Journal of Central South University 2008年第S1期15卷 76-79页

作者：赵才贤张平陈广兵王霞瑜 Institute of Fundamental Mechanics and Material Engineering Xiangtan University Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education Xiangtan University

A novel polyamide 6/silica nanocomposite containing epoxy resins(EPA6N) was prepared via in situ polymerization using tetraethoxysilane(TEOS) as the precursor of silica.The dynamic rheological properties of pure PA6 and EPA6N at temperatures of 225 and 235 ℃ were investigated.The results of transmission electron microscopy(TEM) and atomic force microscopy(AFM) indicate that the silica particles are well dispersed in the polyamide 6 matrix on about 30 nm in diameter,which demonstrates that this method can effectively avoid agglomeration of the inorganic particles.The rheological results suggest that pure PA6 shows Newtonian behavior.However,the novel EPA6N exhibits a solid-like rheological behavior,which is due to the small size,large surface of silica particles and the stronger polyamide 6-silica chemical bond formed through the reactions of epoxy resins with end groups of PA6 molecular chains.The EPA6N also exhibits higher melt viscosity,storage modulus and loss modulus than those of pure PA6.

关键词： polyamide 6 nanocomposites epoxy resins rheological behavior viscosity

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Shape Memory Epoxy Resin and Its Composites:From Materials to Applications

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Research 2022年第2期2022卷 345-369页

作者： Lan Luo Fenghua Zhang Jinsong Leng Centre for Composite Materials and Structures Harbin Institute of Technology(HIT)Harbin 150080China

Shape memory polymers(SMPs)have historically attracted attention for their unique stimulation-responsive and variable stifness and have made notable progress in acrospace,civil industry,and other fields.In particular,epoxy resin(EP)has great potential due to its excellent mechanical properties,fatigue resistance,and radiation resistance.Herein,we focus on the molecular design and network construction of shape memory epoxy resins(SMEPs)to provide opportunities for performance and functional regulation.Multifunctional and high-performance SMEPs are introduced in detail,including multiple SMEPs,two-way SMEPs,outstanding toughness,and termperature resistance.Finally,emerging applications of SMEP's and their composites in aerospace,four-dimensional printing,and self-healing are dermonstrated.Based on this,we point out the challenges ahead and how SMEPs can integrate performance and versatility to meet the needs of technological development.

关键词： composites printing resins

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Monosized macroporous resins with epoxy groups and their structure and gel chromatography properties

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Chinese Science Bulletin 2000年第3期45卷 220-223页

作者： Chao Jin Yanguo Yang Zhongzhang Zhao Shuming Yang Xiulan Tian Tiansheng Su Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

The monosized macroporous-polymer beads based on cross-linked poly(glycidylmethacrylate) have been synthesized by a new improving method-combining dispersionpolymerization with swelling polymerization and polymeric solution porogens. The structure and gel chromatographic properties of the resins have been studied. The resins as matrix materials of various types of high performance liquid chromatography (HPLC) packings possess excellent separation

关键词： : cross-linked poly(glycidyl methacrylate) beads monosized macroporous resins HPLC packings.

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Science China Chemistry 2010年第9期53卷 1844-1852页

作者： WANG Zheng1,YANG RuLei1,ZHU JunDong & ZHU XiaoXia2 1School of Pharmaceutical Science and Technology,Tianjin University,Tianjin 300072,China 2Département de chimie,Université de Montréal,Montréal,QC H3C 3J7,Canada School of Pharmaceutical Science and Technology Tianjin University Tianjin China Département de chimie Université de Montréal Montréal Canada

Combinatorial chemistry has become a significant part of the discovery and optimization process for novel drugs,affinity ligands,and catalysts.The polymeric supports play a key role in combinatory chemistry.Therefore,various kinds of functional polymer resins have been exploited as supports,reagents,and catalysts in organic synthesis.In comparison to the conventional Merrifield resins,the poly(ethylene glycol)(PEG)-related polymer resins have advantages including good compatibilities with polar solvents,good solvent absorbency and swelling properties.This review focuses primarily on the more recent work in the field of developing PEG-related polymer resins as supports for organic synthesis.

关键词： combinatorial chemistry polymer resins poly(ethylene glycol) organic synthesis

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