scholarly journals Effect of Toughening with Different Liquid Rubber on Dielectric Relaxation Properties of Epoxy Resin

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 433 ◽  
Author(s):  
Chuang Wang ◽  
Qing Sun ◽  
Kang Lei ◽  
Chi Chen ◽  
Lixiao Yao ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
High Performance ◽  
Critical Role ◽  
Relative Dielectric Constant ◽  
Interfacial Polarization ◽  
Rubber Composites ◽  
Liquid Rubber ◽  
Rubber Composite ◽  
Industrial Use ◽  
Dielectric Relaxation Properties

Liquid rubber is a common filler introduced to epoxy resin to improve its toughness for electrical insulation and electronic packaging applications. The improvement of toughness by adding liquid rubber to epoxy resin leads to the variation of its dielectric properties and relaxation behaviors and it has not been systematically studied yet. In this paper, four kinds of liquid rubber with different polarity were selected and the corresponding epoxy/liquid rubber composites have been prepared. By analyzing the temperature and frequency dependence of dielectric spectra, we found that a lower relative dielectric constant and dielectric loss of the epoxy/liquid rubber composites could be achieved by reducing the polarity of liquid rubber filler. These results also confirm that the polarity of liquid rubber plays a critical role in determining the α transition relaxation strength of rubber molecules at about −50 °C, as well as the relaxation time of interfacial polarization. In addition, the conductivity of rubber phase with different polarity were investigated by studying the apparent activation energy of interfacial polarization calculated from the Arrhenius plot. This study can provide a theoretical basis for designing high-performance epoxy/liquid rubber composite insulating materials for industrial use.

scholarly journals High-Performance Triboelectric Devices via Dielectric Polarization: A Review

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Minsoo P. Kim ◽  
Doo-Seung Um ◽  
Young-Eun Shin ◽  
Hyunhyub Ko
Keyword(s):  
Dielectric Constant ◽  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
High Performance ◽  
Critical Factor ◽  
Relative Dielectric Constant ◽  
Interfacial Polarization ◽  
Surface Functional Group ◽  
Dielectric Polarization

AbstractEnergy harvesting devices based on the triboelectric effect have attracted great attention because of their higher output performance compared to other nanogenerators, which have been utilized in various wearable applications. Based on the working mechanism, the triboelectric performance is mainly proportional to the surface charge density of the triboelectric materials. Various approaches, such as modification of the surface functional group and dielectric composition of the triboelectric materials, have been employed to enhance the surface charge density, leading to improvements in triboelectric performances. Notably, tuning the dielectric properties of triboelectric materials can significantly increase the surface charge density because the surface charge is proportional to the relative permittivity of the triboelectric material. The relative dielectric constant is modified by dielectric polarization, such as electronic, vibrational (or atomic), orientation (or dipolar), ionic, and interfacial polarization. Therefore, such polarization represents a critical factor toward improving the dielectric constant and consequent triboelectric performance. In this review, we summarize the recent insights on the improvement of triboelectric performance via enhanced dielectric polarization.

scholarly journals Surface Modification of Staple Carbon Fiber by Dopamine to Reinforce Natural Latex Composite

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 988
Author(s):  
Xiaolong Tian ◽  
Shuang Han ◽  
Qianxiao Zhuang ◽  
Huiguang Bian ◽  
Shaoming Li ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
High Performance ◽  
Dynamic Mechanical Properties ◽  
Rubber Matrix ◽  
National Defense ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Thermal And Electrical Properties ◽  
Surface Modified ◽  
Poor Adhesion

Carbon fiber significantly enhances the mechanical, thermal and electrical properties of rubber composites, which are widely used in aerospace, military, national defense and other cutting-edge fields. The preparation of a high-performance carbon fiber rubber composite has been a research hotspot, because the surface of carbon fiber is smooth, reactive inert and has a poor adhesion with rubber. In this paper, a high-performance rubber composite is prepared by mixing dopamine-modified staple carbon fiber with natural latex, and the mechanisms of modified carbon fiber-reinforced natural latex composite are explored. The experimental results show that the surface-modified staple carbon fiber forms uniform and widely covered polydopamine coatings, which significantly improve the interface adhesion between the carbon fiber and the rubber matrix. Meanwhile, when the concentration of dopamine is 1.5 g/L and the staple carbon fiber is modified for 6h, the carbon fiber rubber composite shows excellent conductivity, thermal conductivity, and dynamic mechanical properties, and its tensile strength is 10.6% higher than that of the unmodified sample.

scholarly journals Dielectric Relaxation Characteristics of Epoxy Resin Modified with Hydroxyl-Terminated Nitrile Rubber

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4128
Author(s):  
Chi Chen ◽  
Qing Sun ◽  
Chuang Wang ◽  
Yue Bu ◽  
Jiawei Zhang ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Epoxy Resin ◽  
Critical Factor ◽  
Interfacial Polarization ◽  
Nitrile Rubber ◽  
Dc Conductivity ◽  
Relaxation Processes ◽  
Liquid Rubber ◽  
Β Relaxation ◽  
Relaxation Characteristics

Utilizing liquid rubber to toughen epoxy resin is one of the most mature and promising methods. However, the dielectric relaxation characteristics of the epoxy/liquid rubber composites have not been studied systematically, while the relaxation behaviours are a critical factor for both micro and macro properties. In this paper, hydroxyl-terminated liquid nitrile rubber (HTBN) is employed to reinforce a kind of room-temperature-cured epoxy resin. The dielectric spectrum is measured and analysed. Results show that two relaxation processes are introduced in the binary composites. The α relaxation of HTBN shows a similar temperature dependence with the β relaxation of epoxy resin. The interfacial polarization leads to an increase of complex permittivity, which reaches its maximum at 70 °C. In addition, affected by interfacial polarization, the thermionic polarization is inhibited, and the samples with filler ratios of 15% and 25% show lower DC-conductivity below 150 °C. In addition, the α relaxation and thermionic polarization of epoxy resin obey the Vogel‒Fulcher‒Tammann law, while the interfacial polarization and DC-conductivity satisfy with the Arrhenius law. Furthermore, the fitting results of the Vogel temperature of α relaxation, glass transition temperature, apparent activation energy of interfacial polarization and DC-conductivity all decline with HTBN content. These results can provide a reference and theoretical guidance for the assessment of dielectric properties and the improvement of the formulation of liquid-rubber-toughened epoxy resin.

Study on Carbon Fiber Reinforced Chloroprene Rubber Composites

2014 ◽  
Vol 1052 ◽  
pp. 254-257 ◽  
Author(s):  
Wei Li Wu ◽  
Jiang Kun Li
Keyword(s):  
Carbon Fiber ◽  
Coupling Agent ◽  
High Performance ◽  
Sem Analysis ◽  
Mechanical And Thermal Properties ◽  
Rubber Composites ◽  
Temperature Resistance ◽  
Rubber Composite ◽  
The Matrix ◽  
Chloroprene Rubber

Due to the low strength of ordinary rubber, poor high temperature resistance and abrasion resistance, limit their service life. In this paper, the high-performance carbon fiber (CF) was used as a reinforcement, the chloroprene rubber (CR) as the matrix, and coupling agent as a compatilizer, prepared carbon fiber/rubber composite materials. The content of carbon fiber was determined by testing the mechanical and thermal properties. The effect of coupling agent on the compatibility between rubber and carbon fiber was studied by using as a bonding agent. The compatibility of the carbon fiber and rubber were analyzed by scanning electron microscope (SEM). The results show that the formula obtained best mechanical properties is 100 phr chloroprene rubber, 12 phr carbon fiber, and 2.5 phr KH-550. And further demonstrate that compatibility of carbon fiber / chloroprene rubber with adding 12phr CF by SEM analysis.

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

scholarly journals Synthesis and Properties of Epoxy Resin Modified with Novel Reactive Liquid Rubber-Based Systems

2021 ◽  
Vol 60 (5) ◽  
pp. 2178-2186
Author(s):  
Rafał Januszewski ◽  
Michał Dutkiewicz ◽  
Marek Nowicki ◽  
Mariusz Szołyga ◽  
Ireneusz Kownacki
Keyword(s):  
Epoxy Resin ◽  
Liquid Rubber ◽  
Reactive Liquid

Interfacial polarization-induced high-k polymer dielectric film for high-performance triboelectric devices

Nano Energy ◽  
2021 ◽  
Vol 82 ◽  
pp. 105697
Author(s):  
Minsoo P. Kim ◽  
Chang Won Ahn ◽  
Youngsu Lee ◽  
Kyoungho Kim ◽  
Jonghwa Park ◽  
...  
Keyword(s):  
High Performance ◽  
Dielectric Film ◽  
Interfacial Polarization ◽  
Polymer Dielectric ◽  
High K

Orthogonal Experiment Analysis of Mechanical Thermal Conductivity on Multi-Component Fillers

2013 ◽  
Vol 753-755 ◽  
pp. 2379-2382
Author(s):  
Shi Meng Xu ◽  
Run Bo Ma ◽  
Jian Hua Du ◽  
Jun Hong Liu ◽  
Qi Jin
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Black ◽  
Orthogonal Experiment ◽  
Experiment Design ◽  
Rubber Composites ◽  
Orthogonal Experiment Design ◽  
Rubber Composite ◽  
Al Powder ◽  
Experiment Analysis

Filled the N330 carbon black, silica T80 carbon black and Al powder and Fe2O3 magnetic nanoparticles, the rubber composites on multi-component electromagnetic fillers were prepared according to orthogonal experiment analysis, and the preliminary experiment conclusions of the filler prescription designs were given; Based on the experiment design, the mechanical properties and thermal conductivity of the rubber composite were tested, and the testing results were analyzed by using variance analysis. Thus, the paper shows that the effects of N330 on rubber mechanical properties are significant, and the effects of Al powder on the rubber thermal conductivity are significant. Moreover, it is highly emphasized in this paper that the orthogonal experiment design must be carefully explored before the tests are executed.

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