超高分子量聚乙烯纤维的等离子体表面处理

本文采用低温等离子体对超高分子量聚乙烯纤维进行表面处理,以改善其与环氧树脂的粘接性能,为进一步研制高性能轻型复合材料提供科学依据。实验结果表明处理后的纤维表面能大大提高,使环氧树脂能良好地浸润纤维;纤维与环氧树脂间粘接强度可提高近5—10倍。本文进一步分析了粘接性能改善的原因,并对粘接强度做出贡献的各种作用进行了综合的定量分析。     

超高分子量聚乙烯(UHMWPE)纤维表面处理对UHMWPE/环氧树脂复合材料界面性能的影响机制

从工程化应用角度研究了常压空气等离子体改性对超高分子量聚乙烯（UHMWPE）纤维/环氧树脂复合材料界面性能的调节机制,主要分析了不同处理时间对UHMWPE纤维表面状态变化的影响,及其对UHMWPE/环氧树脂复合材料界面黏结性能的影响规律。采用SEM及纤维吸水测试研究了等离子体处理对UHMWPE纤维表面物理形貌及纤维表面浸润性能的影响,分别以拉伸和弯曲的方式,通过纤维表面脱黏力及层合板层间剪切强度对UHMWPE/环氧树脂复合材料的界面黏结性能进行表征。结果表明,仅经过4 s的空气等离子体处理之后,UHMWPE纤维表面脱黏力的提高幅度为84.0%,UHMWPE/环氧树脂复合材料层合板的层间剪切强度由未处理的7.01 MPa提高至15.81 MPa,增幅高达125.5%。研究发现,通过常压空气等离子体处理改变了UHMWPE纤维的表面状态,可以显著高效地调节UHMWPE/环氧树脂复合材料的界面性能,为扩大该材料的后续工程化应用提供了理论基础。      

低温等离子体表面处理对超高分子量聚乙烯纤维-环氧树脂粘接性能的影响及机理

超高分子量聚乙烯纤维与环氧树脂的粘接性能很差,给高性能轻型复合材料的研制带来困难。本文采用低温等离子体对纤维表面进行处理。结果表明,处理后的纤维表面能提高,使环氧树脂能良好地浸润纤维,纤维与环氧树脂间粘接强度可提高5-8倍。粘接性能改善的原因是:由表面引入的多种含氧基团所形成的化学键力,由表面刻蚀坑产生的机械嵌合力。     

低温等离子体表面处理对超高分子量聚乙烯纤维-环氧树脂粘接性能的影响及机理

超高分子量聚乙烯纤维与环氧树脂的粘接性能很差,给高性能轻型复合材料的研制带来困难。本文采用低温等离子体对纤维表面进行处理。结果表明,处理后的纤维表面能提高,使环氧树脂能良好地浸润纤维,纤维与环氧树脂间粘接强度可提高5-8倍。粘接性能改善的原因是:由表面引入的多种含氧基团所形成的化学键力,由表面刻蚀坑产生的机械嵌合力。      

超高分子量聚乙烯纤维增强防弹复合材料研究进展

介绍了超高分子量聚乙烯(UHMWPE)纤维的特点、种类及编织结构,分析了UHMWPE纤维复合材料的防弹机理,总结了UHMWPE纤维的编织结构、树脂基体性能、界面性能等因素对防弹性能的影响,归纳了UHMWPE纤维防弹复合材料的优缺点,并对UHMWPE纤维复合材料的发展进行了展望。     

超高分子量聚乙烯纤维在防弹材料上的应用

本文就超高分子量聚乙烯纤维作为一种防弹材料 ,综述了其性能特点及在防弹材料上的应用     

超高分子量聚乙烯纤维增强对木材破坏形貌及承载性能影响

选用PUR木材层压胶,设计"刨光锯材-超高分子量聚乙烯(UHMWPE)纤维-单板"3层结构木质复合材,探索研究了UHMWPE纤维增强对木材抗弯性能、剪切性能以及单板厚度对其增强效果影响,并利用红外光谱(FT-IR)对脱粘纤维进行表征,进而对UHMWPE纤维增强机理进行了分析。结果表明,PUR木材层压胶可用于UHMWPE纤维/木材的复合,UHMWPE纤维增强明显改变了木材破坏过程和破坏形貌,提高了木材的承载性能,同时UHMWPE纤维增强效果与单板厚度密切相关。UHMWPE纤维的加入降低了胶合界面的剪切性能。     

铬酸氧化法改善超高分子量聚乙烯纤维表面粘接性能

以特定浓度铬酸氧化液对超高分子量聚乙烯(UHMWPE)纤维进行表面氧化改性。通过傅里叶变换红外光谱、X射线光电子能谱、扫描电子显微镜、X射线衍射和力学性能测试分析比较了处理前后纤维的表面官能团变化、形貌结构、结晶性能和力学性能的变化,并采用微脱粘法和拉曼光谱法研究了纤维-树脂复合材料界面剪切强度及微观受力情况。结果表明,UHMWPE纤维经铬酸氧化处理后,纤维表面极性增加,粗糙程度变大;纤维表面处理的最佳条件为55℃、5min;拉曼光谱研究表明,改性后UHMWPE纤维-环氧树脂界面粘接性能较未改性纤维有明显增强。     

电晕处理对高性能PBO纤维的表面性能及其界面粘接性能的影响

对高性能PBO纤维表面进行了电晕处理,优化了其处理工艺。用XPS,FT-IR和SEM研究了处理前后纤维表面化学结构及物理结构的变化,通过单丝拔出试验和短梁剪切试验评价了PBO纤维与树脂基体的微宏观界面粘接性能。结果表明:经电晕处理后,PBO纤维表面含氧量增多,表面浸润性得到改善,单丝拔出的PBO-环氧界面剪切强度(IFSS)提高了25.6 ％,但短梁剪切强度(ILSS)的提高不明显。     

超高分子量聚乙烯纤维表面改性及其界面性能研究进展

超高分子量聚乙烯(UHMWPE)纤维因具有高化学稳定性,高机械性能和低成本等优点而成为理想增强材料之一。然而,规整的非极性分子链结构致使UHMWPE纤维结晶度高、与树脂基体之间几乎无化学键合,本文因而与树脂的粘合性差。为此已经进行了许多纤维表面处理的工作,如紫外辐射、等离子体处理、聚合物涂层等。主要从湿法化学改性和干法化学改性这两方面入手,总结归纳了目前超高分子量聚乙烯纤维的界面改性研究现状,从物理和化学两个方面揭示界面增强机理以及界面性能与复合材料力学性能的关系,为超高分子量聚乙烯纤维的界面结构设计和改性提供科学理论依据和技术指导。     

输电线路电晕振动特性研究及分析

摘要：输电线路导线电晕放电产生离子风,在离子风作用下输电导线产生涡致振动。为了研究输电导线电晕振动特性,分析了导线电晕放电的场强和离子风的产生机理和影响因素,并建立了输电导线电晕涡致振动方程。采用龙格-库塔法计算了220KV输电线路电晕振动的动力响应,分别研究了导线表面状态、空气湿度和密度、输电导线结构尺寸和张力等对振幅的影响及抑制措施。分析方法和结论,可为特高压输电线路设计、已有线路升级改造以及振动抑制提供必要参考。     

Effects of part geometry and injection molding conditions on the tensile properties of ultra-high molecular weight polyethylene polymer

In this study, the influences of process parameters and different cross-sectional dimensions on the tensile strength of specimens with and without a weld line are investigated. In addition, the weld line characteristics of structures with different cross-sections are explored as well. With the Taguchi method and confirmation test, it can be concluded that Taguchi method is suitable to improve the mechanical properties occurring in the injection molded UHMWPE parts. The single-factor experimental results indicate that the process parametric influence is relatively smaller than the cross-sectional dimensions on the tensile strength of specimens without weld line. The experimental observations present that the frictional heating can be enhanced the molecular bonding and self-diffusion in the frozen layer of two sides on the weld line region. The SEM images showed that the micro-voids, cracks and incomplete molecular bonding are the major surface defects on the weld line region.     

超高分子量聚乙烯纤维复合材料用树脂基体的研究进展

本文从提高超高分子量聚乙烯 (UHMWPE)纤维与基体的粘接性入手 ,介绍了目前UHMWPE纤维复合材料常用的聚氨酯类、橡胶类、乙烯酯类树脂体系的特点和应用现状及前景。分析了UHMWPE纤维复合材料作为防弹材料、结构材料等的优点和目前所存在的问题 ,针对这些问题提出了解决的思路。     

Mechanism of cement paste reinforced by ultra-high molecular weight polyethylene powder and thermotropic liquid crystalline copolyester fiber with enhanced mechanical properties

In this study, a series of cementitious composites with high toughness and flexural strength was obtained by melt-dispersing ultra-high molecular weight polyethylene (UHMWPE) into a cement matrix followed by water immersion. The structure and chemical composition of the composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Three point bending tests showed that the flexural strengths of the composites were improved from 5.5 MPa to 18.2 MPa with the presence of 25 wt% UHMWPE, and could be further enhanced to 28.1 MPa with the addition of only 0.1 vol% oriented thermotropic liquid crystalline copolyester (TLCP) fibers. An adhesive test revealed that the interfacial binding force between polymer and fiber was much stronger than that between cement and fiber. Our findings provide a simple way for utilizing polymer to improve the interface between the fibers and cement matrix, consequently achieving a dramatic increase in the flexural strength and toughness.     

Modeling of the production of OH and O radicals in a positive pulsed corona discharge plasma

A mathematical model was applied to describe the behavior of OH and O radicals in positive pulsed corona discharge of N₂-H₂O mixture gas. The model takes into account the generation and disappearance of radials in a pulsed corona discharge reactor by a single pulse or continuous pulses. Their concentrations were derived by considering direct electron effect on the dissociation of gaseous molecules (O₂, N₂, H₂O) and subsequent excitation transfer reaction of excited oxygen atoms to produce OH radicals. The equations promoted could be solved numerically with the FORTRAN subroutine Treanor. So as to establish the validity of the model simulation, the calculated results were compared with the experimental data. Although there is some discrepancy between the calculation and experiment, the total trend is coincident.     

Enhancement on interlaminar shear strength and tribological properties in water of ultra high molecular weight polyethylene/glass fabric/phenolic laminate composite by surface modification of fillers

The ternary laminate composite of ultra high molecular weight polyethylene (UHMWPE)/high strength glass fabric (S-glass fabric)/phenolic resin was prepared, in which UHMWPE microparticles were etched by chromic acid and S-glass fabrics were treated by silane coupling agent. The interlaminar shear strength (ILSS) and tribological properties of the composite in water environment were investigated, in comparison with those of the composite without any treatments on fillers and the composite with single treatment on UHMWPE. Results showed that the composite with the combined treatment exhibited the best interfacial bond, accordingly showing remarkably enhanced water repellency, ILSS and tribological properties under water lubrication. Furthermore, after experiencing 48 h water immersion, the composites with both single and combined treatment did not suffer any degradation of ILSS and water-lubricated tribological performances, showing excellent duration in water environment.     

超高分子量聚乙烯的生物摩擦学

结合超高分子量聚乙烯(UHMWPE)的磨损机制,综述了通过改性,如离子注入、填料改性等,提高UHMWPE的耐磨性研究,并对其发展方向进行了有益探讨.     

The barrier discharge: basic properties and applications to surface treatment

Barrier discharges (BDs) produce highly non-equilibrium plasmas in a controllable way at atmospheric pressure, and at moderate gas temperature. They provide the effective generation of atoms, radicals and excited species by energetic electrons. In the case of operation in noble gases (or noble gas/halogen gas mixtures), they are sources of an intensive UV and VUV excimer radiation. There are two different modes of BDs. Generally they are operated in the filamentary one. Under special conditions, a diffuse mode can be generated. Their physical properties are discussed, and the main electric parameters, necessary for the controlled BD operation, are listed. Recent results on spatially and temporally resolved spectroscopic investigations by cross-correlation technique are presented. BDs are applied for a long time in the wide field of plasma treatment and layer deposition. An overview on these applications is given. Selected representative examples are outlined in more detail. In particular, the surface treatment by filamentary and diffuse BDs, and the VUV catalyzed deposition of metallic layers are discussed. BDs have a great flexibility with respect to their geometrical shape, working gas mixture and operation parameters. Generally, the scaling-up to large dimensions is of no problem. The possibility to treat or coat surfaces at low gas temperature and pressures close to atmospheric once is an important advantage for their application.     

Sintering of ultra high molecular weight polyethylene

Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer having low coefficient of friction, good abrasion resistance, good chemical resistance etc. It is used in shipbuilding, textile industries and also in biomedical applications. UHMWPE is processed by powder processing technique because of its high melt viscosity at the processing temperature. Powder processing technique involves compaction of polymeric powder under pressure and sintering of the preforms at temperature above its melting point. In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering temperatures and strength development.     

对偶件表面粗糙度对UHMWPE摩擦磨损性能的影响

人工关节在服役过程中的磨损主要发生在超高分子量聚乙烯(UHMWPE)关节臼的表面。UH-MWPE的磨擦磨损性能受多因素影响,其中与UHM-WPE对磨的硬质材料(对偶件)表面粗糙度是关键因素之一。综述了近年来在对偶件表面粗糙度对UH-MWPE摩擦磨损性能影响方面的研究工作,结合UHMWPE的磨损机制,重点阐述对偶件表面粗糙度对UHMWPE磨损率、UHMWPE磨屑尺寸和人工关节润滑机制的影响。