New ways to improve the damping properties in high‐performance thermoplastic vulcanizates

The incorporation of viscoelastic materials represents an effective strategy to reduce the vibratory level of structural components. Thermoplastic vulcanizates (TPVs) are a special type of viscoelastic material that combines the elastomeric properties of rubbers with the easy processing of thermoplastics. In the present work, we propose innovative ways to improve the damping properties of high‐performance TPVs by using rubbers with carboxylic functionalities. For that, TPVs from physical blends of carboxylated hydrogenated acrylonitrile butadiene rubber (XHNBR) and polyamide 6 (PA6) were prepared. The chain dynamics of different mixed crosslink systems containing peroxide, metal oxides and hindered phenolic antioxidants were investigated in order to find the most suitable strategy to design a high‐performance TPV system with upgraded damping properties. The results indicate that the damping performance of the TPV system can be tailored by controlling the type and magnitude of the bonding interactions between the mixed crosslink system and the XHNBR rubber phase. Therefore, this study demonstrates the potential of TPV systems containing carboxylic rubbers as high‐performance damping materials. © 2020 Society of Chemical Industry     

一维多壁碳纳米管增强丁基橡胶/聚丙烯热塑性弹性体复合材料的相态结构及热电性能研究

制备一维多壁碳纳米管(MWCNTs)增强丁基橡胶(IIR)/聚丙烯(PP)动态硫化热塑性弹性体(TPV)复合材料,研究IIR/PP用量比(简称橡塑比)对复合材料相态结构、介电性能、导热性能和物理性能的影响。结果表明:复合材料呈现“海-岛”相结构,IIR相以微米级交联颗粒分散在PP相中;MWCNTs主要分散在PP中,随着橡塑比的增大,MWCNTs有少量团聚现象;随着橡塑比的增大,复合材料的交流电导率、介电常数和热导率增大,且橡塑比大于6/4时增速减小;随着橡塑比的减小,复合材料的拉伸强度先增大后减小;当橡塑比为5.5/4.5时,复合材料的物理性能较好。     

Effectiveness analysis and optimum design of the rotary regenerator for thermophotovoltaic (TPV) system

The influence of the period of rotation on the effectiveness of the thermophotovoltaic (TPV) rotary regenerator was theoretically and experimentally investigated.It was found that the deviations of the...     

密封条在汽车上的设计趋势

研究密封条在汽车上的应用,分别从密封条组成材料和设计的角度分析了将来汽车行业密封条的发展。结果表明,低成本、轻量化、高可靠性是将来密封条发展的趋势。     

Performance of a mesoscale liquid fuel‐film combustion‐driven TPV power system

Combustion‐driven thermophotovoltaic (TPV) systems have obtained increasing attention in recent decades, but most studies have focused on developing narrowband photovoltaic cells and selective emitters. In terms of the heat source, conventional combustion configurations and light gaseous fuels are extensively utilized in macro‐ or meso‐scale TPV power systems to simplify thermal management and mechanical fabrication. As far as miniaturization is concerned, however, fuelling these systems with liquid hydrocarbons would provide inherent advantages of high energy density and low volatility. Liquid fuels also promise easy and safe fuel recharging for small‐scale power systems. In this paper, a central porous‐medium combustor was employed in a small scale TPV power system. The combustor incorporated an emitting chamber wall and a heat recuperator. The radiant efficiency and overall efficiency were compared using different liquid hydrocarbon fuels in the system. The electric output characteristics of the combustion driven TPV system have been investigated to demonstrate the feasibility of a GaSb cell‐based TPV power system and to provide design guidance for mesoscale liquid‐burning TPV systems. Copyright © 2008 John Wiley & Sons, Ltd.     

热光伏系统性能匹配性研究

针对热光伏(TPV)系统建立了数值分析模型,研究了系统各模块的匹配特性,讨论了辐射器温度、散热器流速等性能参数对电池温度及输出功率的影响,并进行了优化组合分析,以获得系统最佳运行工况。结果表明:在每一特定辐射器温度下,都存在一最优散热器入口流速以使得系统效率达到最大。随着辐射器温度的升高,TPV系统效率及输出净功率均随之增大,但由于电池温度的升高,系统效率增长梯度逐渐减缓。当辐射温度达到1 800K时,系统效率最高可达到18.22%。     

热塑性弹性体的新进展

对近年来最热门的动态交联型热塑性弹性体（TPV），已在市场上见到的5类材料作了简要概述。对其中的聚苯乙烯类（TPS）的生产厂家和生产能力列表给出详细资料。我国是世界最大的TPE消费国，在生产和应用最有发展潜力的TPO（烯烃类）和TPV方面只是刚刚开始。     

Morphology Development in Novel Composition of Thermoplastic Vulcanizates Based on PA12/PDMS Reactive Blends

The main objective of the present work was to tailor a new thermoplastic vulcanisate (TPV) composed of PA 12 as the thermoplastic phase and PDMS as the rubber phase. The PDMS was crosslinked by dicumyl peroxide (DCP). Interestingly, addition of 2,2,6,6‐tetramethylpiperidinyloxyl (TEMPO) to the TPV provided the compatibilization of the PA12/PDMS blend in the dynamic process and gave a new material with control structure and morphology. The electron microscopy (SEM and TEM) studies revealed that adding silica nanoparticles and Lotader in PA12 and PDMS phases, respectively, led to a drastic reduction in R_v of the PDMS particles from 16.5 µm (virgin blend) to nearly 0.6 µm for the PA12/PDMS reactive blend. Therefore, a stable co‐continuous morphology was obtained for the new TPV based on 60–40 wt.‐% of PDMS‐PA12 blend.

     

TPV及PP-g-MAH对回收PET的改性研究

以马来酸酐接枝聚丙烯(PP-g-MAH)为相容剂,回收聚对苯二甲酸乙二醇酯(rPET)为基体材料,动态硫化热塑性弹性体(TPV)为增韧材料,制备了rPET/TPV/PP-g-MAH共混物。用SEM、DMA及DSC分析了TPV及PP-g-MAH对rPET断面结构、储能模量和结晶性能的影响,并测试了共混物的力学性能。结果表明:加入9.95%TPV后,rPET/TPV共混物的熔融温度下降了2.33℃,结晶温度提高了2.82℃,断裂伸长率及缺口冲击强度明显提高,弯曲强度和拉伸强度略有下降;加入PP-g-MAH后,TPV球状粒子嵌入rPET基体材料中,共混物的相容性提高,储能模量明显增大,刚性增强,弯曲强度和拉伸强度有所提高;与纯rPET相比,含1.8%PP-g-MAH的rPET/TPV/PP-g-MAH共混物的断裂伸长率提高了129.06%,缺口冲击强度提高了47.02%。     

Effect of spatial confinement on the development of β phase of polypropylene

The focus of this study was the effect of spatial confinement on the development of nucleating agent-induced β phase polypropylene (PP) in the dynamically vulcanized thermoplastic elastomers (TPVs) based on dynamically vulcanized PP/ethylene-propylene-diene rubber (EPDM) blend. The melting behaviors, crystalline structures and the morphologies of the blends were studied by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). The results indicate that the EPDM phase undergoes a series of changes from the dispersed phase to a continuous one, and again to the dispersed phase with increased content of curing agent, and the PP component always shows itself in a continuous phase. In this process, with the content of the nucleating agent unchanged, the content of β phase PP in the blends initially increases a little and then decreases with increasing PF (Phenolic resin) content. We believe spatial confinement provides a good explanation for the development of β phase PP.