非平衡热力学在摩擦领域聚合物复合材料设计中的应用

以自润滑材料和摩擦材料为例,基于非平衡热力学原理从热量产生和传递的根本问题出发,研究摩擦系数和热导率对材料接触面温度的影响,指导聚合物基复合材料的设计。对于自润滑材料来说,将摩擦热量产生和传递过程假设成两个过程的串联,发现摩擦热产生是摩擦系统整体稳定运行的关键控制因素。对于摩擦材料来说,将摩擦热量传递过程假设成传递热量和分配热量两个过程的并联,发现需采用降低刹车片热导率的逆向思维降低接触面温度。     

碳纳米管在聚合物摩擦材料中的应用

综述了近年来碳纳米管(CNTs)在改善热固性树脂和热塑性树脂摩擦性能方面的研究进展,并展望了聚合物/CNTs摩擦材料今后的研究方向.     

工程用聚合物基复合材料摩擦行为研究进展

综述了复合改性聚合物材料摩擦磨损性能研究发展 ,主要分析了纤维、金属及其化合物、无机非金属化合物及聚合物填料对材料摩擦性能的影响和作用机理 ,以及工况条件及摩擦磨损形式对材料摩擦行为的影响 ,简述了复合材料摩擦行为模拟及预测的研究现状及研究中存在的问题 ,进一步探讨了材料摩擦行为模拟和预测的可能性。     

聚合物减摩自润滑材料在汽车中的应用

综述了聚合物减摩自润滑复合材料在汽车中的应用,对基体树脂的选择、减摩组分和抗摩增强组分的选择与匹配以及复合材料的摩擦机理进行了分述;提出了改善复合材料的减摩自润滑性能的几种途径,为正确设计减摩性聚合物基复合材料提供了依据。     

聚合物复合材料在汽车制造中的应用

国外的大公司,诸如通用发动机公司、Porchet 公司、菲亚特公司、杜邦公司、帝国化学工业公司(英)、拜耳公司和其他公司在苏联展出汽车,汽车的全部零件实际上是采用最新的聚合物复合材料制造。这种汽车比原型钢板汽车轻50～60%,具有油耗小(100km 路程油耗仅2～4L),较大的改进空气动力学性和寿命长的特点。此外汽车不需要防腐蚀的特殊的保护层。一般常用薄钢板制造汽车承受负荷最主要的零件是悬架零件(各种钢板弹簧)、万向轴、保险杠和传动零件。这些零件用的材料都是强度高、刚度硬、疲劳强度高、抗扭强度高,以连续玻璃纤维、碳纤维和芳香聚     

玻璃纤维在摩擦材料领域的应用

玻璃纤维在摩擦材料领域的应用东台玻璃纤维厂陶毕华朱瑞宏南京玻璃纤维研究设计院曾天卷１课题的提出石棉是一类经过机械加工后可以分解成矿物纤维的水化硅酸盐的总称。石棉具有优异的物理化学性能：不燃烧、不霉烂、具有很高抗拉强度、耐酸、酸碱、耐热性能优良，石棉纤...     

聚合物/纳米无机粒子摩擦复合材料研究进展

综述了纳米无机粒子聚合物摩擦材料的耐磨机理及其性能,讨论了影响复合材料摩擦性能的因素     

热力学及热力学参数状态图在SiAlON材料合成中的应用

热力学和热力学参数状态图在材料的合成和设计中起着重要的理论指导作用。文中对其基础理论知识进行了概述,重点讲述了它们在确定碳热还原氮化法合成O’SiAlON粉及热压烧结合成βSiAlON-15R复相材料的工艺条件和温度制度中的应用,并对其应用前景进行了展望。     

碳纤维/聚合物自润滑复合材料的机械及摩擦性能

采用以钢铁为基体高分子自润滑复合材料为衬层制作的传动件,兼有优良的减磨耐磨性能和高的承载能力。研究了组分对复合材料性能的影响,制备了机械和摩擦学性能好的碳纤维增强复合材料,其黏结强度和压缩强度分别达到16~18 MPa和85~91 MPa,冲击强度达19.67~23.45 kJ/m2;与锡青铜ZQSn6-6-3摩擦对比试验表明,复合材料在重载工况下具有更优良的摩擦性能,工作状况稳定,油摩擦因数为0.077,仅为ZQSn6-6-3的59%。试验还发现,轻载启动和在摩擦面开设润滑油槽有助于改善摩擦状况。     

Quick-response polymer humidity control composites and application in preservation of fruits and vegetables

A novel intelligent moisture-controlling polymer composite (IMCPC) with fast response humidity control performance, which can be applied in refrigerators for edible fruits and vegetables, was prepared by intercalation polymerization of acrylamide (AM) with sepiolite. The performance of the resulted IMCPCs was investigated. The results show that vacuum freeze-dried polyacrylamide/sepiolite composite has a porous structure and excellent moisture absorption properties. The IMCPC responds quickly within 30 min both in high and low humidity inside the refrigerator, maintaining relative humidity in the higher range (80–87% RH). It can effectively extend the storage of fruits and vegetables in the refrigerator box. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48883.     

Detailed thermodynamics for analysis and design of Ranque‐Hilsch vortex tubes

The Ranque‐Hilsch vortex tube is a device for continuously separating an inlet pressurized fluid stream into two outlet streams of warmer and cooler temperatures at lower pressures, with no moving parts and without any heat or work effects. It has been applied to cool or heat small systems where refrigeration is impractical. Studies of the fluid mechanics inside the tube have not fully established the flow structure that provides the separation. Thermodynamic energy and entropy balances giving relations among properties and the relative amounts of the three fluid streams have been examined to determine consistency among measured data along with sensitivity of the phenomena to tube configuration, measurement error, and properties. The strong response of the temperature separation to small variations in entropy generation is shown to limit the possibilities for generalized prediction of vortex tube behavior. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1067–1074, 2018     

碳纳米管的制备及其聚合物基复合材料的研究进展

本文综述了单壁碳纳米管的制备方法,重点阐述了化学气相沉积法的合成运用,并对目前碳纳米管在聚合物基纳米复合材料方面的研究做了综合阐述。     

Preparation and tribological behavior of polytetrafluoroethylene/metal mesh composites with sandwich structure

Polytetrafluoroethylene (PTFE) owns an excellent self-lubricating performance, but its wear rate is very high due to the large-scale spalling of the matrix in the friction. In this paper, A new kind of PTFE composites with sandwich structure was prepared by layer-press technology, whose middle layer is filled with metal mesh. The influence of the mesh structure and mesh density of middle metal layer on tribological properties of composites were researched in detail. The results revealled that the metal mesh located in the composites can efficiently prevent the large-scale spalling of PTFE, which induces the sample of PTFE/500# plain woven dutch metal mesh (PTFE-500#PWD) to have a lower wear rate (9 × 10⁻⁵ mm³/Nm) and COF (0.106) under the fixed experimental condition. The prepared PTFE/metal mesh composites reveal excellent anti-friction and anti-wear performance, which can be used to fabricate a new kind of self-lubricating materials.     

Non-equilibrium thermodynamic analysis of coupled heat and moisture transfer across a membrane

Non-equilibrium thermodynamics theory is used to analyze the transmembrane heat and moisture transfer process, which can be observed in a membrane-type total heat exchanger (THX). A theoretical model is developed to simulate the coupled heat and mass transfer across a membrane, total coupling equations and the expressions for the four characteristic parameters including the heat transfer coefficient, molar-driven heat transfer coefficient, thermal-driven mass transfer coefficient, and mass transfer coefficient are derived and provided, with the Onsager’s reciprocal relation being confirmed to verify the rationality of the model. Calculations are conducted to investigate the effects of the membrane property and air state on the coupling transport process. The results show that the four characteristic parameters directly affect the transmembrane heat and mass fluxes: the heat and mass transfer coefficients are both positive, meaning that the temperature difference has a positive contribution to the heat transfer and the humidity ratio difference has a positive contribution to the mass transfer. The molar-driven heat transfer and thermal-driven mass transfer coefficients are both negative, implying that the humidity ratio difference acts to reduce the heat transfer and the temperature difference works to diminish the mass transfer. The mass transfer affects the heat transfer by 1%–2% while the heat transfer influences the mass transfer by 7%–14%. The entropy generation caused by the temperature difference-induced heat transfer is much larger than that by the humidity difference-induced mass transfer.     

石墨烯复合材料的研究及其应用

综述了石墨烯复合材料的结构和分类,主要包括石墨烯-纳米粒子复合材料、石墨烯-聚合物复合材料和石墨烯-碳基材料复合材料,并简述石墨烯复合材料在催化领域、电化学领域、生物医药领域和含能材料领域的应用。     

Effect of silk fiber to the mechanical and thermal properties of its biodegradable composites

In recent years, natural fiber‐reinforced biodegradable thermoplastics are being recognized as an emerging new environmentally friendly material for industrial, commercial, and biomedical applications. Among different types of natural fibers, silk fiber is a common type of animal‐based fiber, has been used for biomedical engineering and surgical operation applications for many years because of its biocompatible and bioresorbable properties. On the basis of our previous study, a novel biodegradable biocomposite for biomedical applications was developed by mixing chopped silk fiber and polylactic acid (PLA) through the injection molding process. This article is aimed at studying the dynamic mechanical and thermal properties of the composite in relation to its biodegradation effect. At the beginning, it was found that the initial storage modulus of a silk fiber/PLA composite increased while its glass transition temperature decreased as compared with a pristine PLA sample. Besides, the coefficient of linear thermal expansions (CLTE) of the composite was reduced by 28%. This phenomenon was attributed to the fiber–matrix interaction that restricted the mobility of polymer chains adhered to the fiber surface, and consequently reduced the T_g and CLTE. It was found that the degraded composite exhibited lower initial storage modulus, loss modulus and tan delta (tan δ) but the T_g was higher than the silk fiber/PLA composite. This result was mainly due to the increase of crystallinity of the composite during its degradation process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical and tribological performance of acrylonitrile-butadiene rubber/carbon black/cryptocrystalline graphite composites

In this study, cryptocrystalline graphite (CG) was investigated as a novel functional filler for acrylonitrile-butadiene rubber (NBR)/carbon black (CB) composites. NBR/CB/CG composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) as well as differential scanning calorimetry (DSC). The results showed that NBR/CB/CG-10 increased by 18.2%, 11.0%, and 10.0% in tensile strength, 300% tensile modulus and tear strength, respectively compared with NBR/CB. Uniform filler dispersion and stronger interfacial interaction contributed to enhancing the mechanical property of NBR/CB/CG composites. It was revealed that the small particle size, rough surface, and defective structure of CG facilitated its exfoliation and intercalation. In addition, the tribological performance of NBR/CB/CG composites was tested on a ring-on-block wear tester under dry sliding conditions. The friction coefficient and specific wear rate of NBR/CB/CG-5 reduced by 50.3% and 51.4%, respectively through the formation of fine lubrication and transfer films. CG enhanced the thermal stability, mechanical, and tribological performance of NBR composites simultaneously and the results of this work proved that CG would be a cost-effective and resource-available functional filler especially suitable for rubber seal application.     

Effect of SiO2 nanoparticles-decorated SCF on mechanical and tribological properties of cenosphere/SCF/PEEK composites

A silicon oxide (SiO₂) nanoparticles-decorated short carbon fiber (SCF) hybrid (SCF-SiO₂) was designed to improve the weak interfacial bonding between fibers and matrix. Nano-SiO₂ was grafted onto carbon fibers by introducing amino group and epoxy group on the surface of carbon fibers and SiO₂, respectively. The chemical composition of SCF-SiO₂ was analyzed by Fourier transform infrared spectrometer and energy-dispersive spectrometry, the microstructure of SCF-SiO₂ were investigated by scanning electron microscope, and then the hybrid filler was introduced into Poly(ether ether ketone) (PEEK). Due to the strong interfacial interaction between filler and matrix, the mechanical and tribological properties of SCF-SiO₂/PEEK composites were significantly better than SCF/PEEK composites. In order to further improve the tribological properties of the composites, micrometer-sized cenosphere (CS) particles were introduced into the aforementioned system to prepare multicomponent composites. The test results of friction and wear indicate that the CS/SCF-SiO₂/PEEK composites have the optimal tribological properties. Compared with pure PEEK, the friction coefficient of CS/SCF-SiO₂/PEEK composites under 200 N load decreases by 56.4% and the specific wear rate decreases by 87.4%. Meanwhile, the thermal decomposition temperature of CS/SCF-SiO₂/PEEK composites is increased by 40 °C compared to pure PEEK. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48749.     

聚合物/碳纳米管复合材料的研究现状及在纤维中的应用

对聚合物/碳纳米管复合材料的制备和性能研究现状及碳纳米管对聚合物的增强机理作了综述,并介绍了此纳米复合材料在复合纤维制备中的应用。