UHMW—PE纤维增强氧基复合材料界面研究

超高分子量聚乙烯纤维经过低温氧等离子体处理后，与环氧树脂基体的界面粘结性能明显改善。本文通过单纤维拔出实验，ＸＰＳ，ＳＥＭ，接触角测算研究了表面改性的作用机理。对影响界面粘结的作用力进行了定量分析，提示了表面刻蚀坑引起的界面机械铰链力，以及由多种含氧极性基团引起的化学键力和界面非极性分子色散力，它们分别对界面粘结强度的贡献，及其随等离子体处理参数的变化关系。     

NiTi纤维表面处理及其树脂基复合材料的界面特性

NiTi纤维表面呈惰性,表面能低,NiTi纤维与树脂间界面粘结性差.为了提高界面性能,采用硅烷偶联剂、表面涂层和低温冷等离子体技术等方法对NiTi纤维表面进行处理,改善纤维表面的浸润性,达到纤维与树脂界面良好的粘结.对复合材料进行界面剪切强度的测定,并利用扫描电镜观察拔脱纤维表面形貌的变化.研究表明:NiTi纤维经不同方法处理后,纤维的浸润性和界面的粘结强度均有不同程度的改变,其中冷等离子体处理的纤维再经硅烷处理,其复合材料IFSS提高2.94倍,ILSS提高1.45倍,且纤维与树脂粘合较好.     

UHMW-PE纤维/环氧树脂界面破坏机理

高分子量聚乙烯(UHMW-PE)纤维经过低温氧等离子体处理后,与环氧树脂的界面粘结性能明显改善。本文通过单纤维拔出实验、SEM、表面能以及界面裂纹能计算等方法研究了界面破坏形式及机理。随着等离子体处理时间的增加,裂纹扩展区域发生了相应变化,即从聚乙烯与树脂的界面逐渐移向纤维内部,导致了相应厚度的纤维表面层被剥落。剥落厚度还与纤维拉伸比有关。     

冷等离子体处理对PET纤维/环氧复合材料界面改性的研究

采用冷等离子体技术对PET纤维进行表面处理,并采用ESCA对处理前后的纤维表面进行了分析。研究了冷等离子体处理工艺参数对PET纤维/环氧复合材料界面剪切强度、横向拉伸强度的影响。实验结果表明:冷等离子体处理可以使PET纤维表面的氧和氮的极性基团含量增加,从而改善其与树脂的浸润性,进而改善PET纤维/环氧复合材料的界面性能。     

氧气DBD等离子体处理PBO纤维表面及其对双马树脂基复合材料界面性能的影响

采用氧气介质阻挡放电(DBD)等离子体处理PBO纤维表面,用以改善PBO纤维与双马来酰亚胺(BMI)树脂之间的界面粘结性能。结果表明,用氧气等离子体处理PBO纤维能大幅度提高PBO/BMI复合材料的层间剪切强度(ILSS)值,最佳处理条件为功率30 W/m³、时间24 s,ILSS值从43.9 MPa提高到62.0 MPa。经过氧气DBD等离子体处理的PBO纤维其表面的氧含量明显提高,氮含量变化不大,甚至在过度处理时降低;官能团-O-C=O基团的含量从0提高到3.16%,-C-O-的含量也明显提高;在氧气DBD等离子体处理后的PBO纤维表面产生大量凹凸不平和沟壑,使纤维表面的粗糙度提高。而表面氧含量的提高和表面形貌与粗糙度的变化,是PBO/BMI复合材料ILSS值提高的重要原因。单丝拉伸实验结果表明,适当的DBD等离子体处理不会对PBO纤维表面产生不良影响,不影响其在复合材料中的作用。     

碳纤维预成型立体织物纤维表面处理及效果评价

对三维正交编织碳预成型物中的纤维表面进行了空气等离子体处理研究,采用微脱粘技术评价了其复合材料的界面结合性能.结果表明,处理后复合材料的界面结合性能有较大幅度的提高,并且织物表层区域纤维表面与织物内部区域纤维表面改性效果基本等同.同时,分析了等离子体处理对碳纤维单丝本体强度的影响.     

连续玄武岩纤维冷等离子改性处理性能研究

采用低温等离子体表面改性处理仪对玄武岩纤维等离子改性,对玄武岩纤维改性前后表面形貌SEM、表面浸润性以及回潮率等的变化进行测试、表征分析。结果表明,未处理的玄武岩纤维表面较为光滑,接触角滞后现象不明显,与树脂基体界面粘结效果不理想,回潮率为0.12%。比较处理时间5min、12min,等离子体改性处理15min刻蚀程度最大,表面最粗糙,回潮率增加到0.83%,而接触角差异达到37.57°,与树脂基体界面粘结效果最好。     

碳纤维表面处理对C/PLA复合材料界面粘结强度的影响(Ⅱ)

对硝酸表面处理前后碳纤维增强聚乳酸（Ｃ／ＰＬＡ）复合材料的界面状态进行了研究。重点研究了碳纤维的硝酸表面处理对Ｃ／ＰＬＡ复合材料界面粘结强度的影响以及粘结机理。研究表明,硝酸表面处理可使复合材料的界面粘结强度大幅度增加,复合材料的冲击强度、弯曲强度、弯曲模量和剪切强度亦有不同程度的提高。ＸＰＳ研究发现,央纤维与ＰＬＡ基体间有化学反应发生。界面化学反应程度的增加是复合材料界面粘结强度提高的主要原因;此外,碳纤维表面粗糙度的增加也对界面粘结强度的提高有一定的贡献。     

偶联剂处理镀镍碳纤维/环氧树脂界面特性

采用硅烷偶联剂KH560对镀镍碳纤维进行偶联处理.通过扫描电镜、红外光谱、接触角测量和单丝复合体系多次断裂法测试研究对比偶联处理前后碳纤维的表面形貌、结构、润湿性能以及纤维/树脂体系的界面状态和粘结性能.结果显示:偶联处理后,镍镀层表面平整,羟基等表面极性基团增加,表面涂覆的KH560膜层完整;镀镍碳纤维/树脂界面的浸润性得到改善;镀镍碳纤维/环氧树脂的界面处没有气泡产生,断点两侧的脱粘现象减轻;单丝饱和断点数由46增加到65;镀镍碳纤维/环氧树脂的界面剪切强度由(34.87±2.23) MPa提高到(72.51±3.77) MPa.     

Technora纤维表面等离子体处理对其复合材料界面性能的影响

用扫描电子显微镜观察Technora纤维表面物理形貌并测量单丝纤维的拉伸强度以分析等离子体处理对纤维本体性能的影响,再用层间剪切强度和吸水率分别表征复合材料在室温干态和高温湿态下的界面性能,研究了等离子体处理对Technora纤维复合材料界面性能的影响。结果表明,用等离子体处理后纤维表面的物理形貌发生了显著变化,复合材料的层间剪切强度由未处理时的15.74 MPa提高到24.93 MPa,提高的幅度高达58.4%;同时,复合材料的吸水率下降而本体性能基本不受影响。上述结果表明,等离子体对Technora纤维的表面改性能有效地改善其复合材料的界面性能。     

高密度聚乙烯纤维表面活化及其与环氧复合材料的界面

采用铬酸氧化法处理聚乙烯纤维（ＨＤＰＥ）表面，并用ＳＥＭ和ＸＰＳ观察．结果表明，纤维表面活性提高，ＨＤＰＥ纤维／环氧树脂基复合材料界面粘接状况得以改善．界面粘接性能改善的主要原因可能是表面处理引入的多种含氧基团与环氧树脂分子中的环氧基团形成化学键力．     

Surface modification and characterization of photodefinable epoxy/copper systems

The effects of the wet-chemical and plasma treatments on the adhesion of electroless and sputter-deposited copper to the photodefinable epoxy have been investigated. The wet-chemical treatment increased the amounts of oxygen-containing functionalities on the epoxy surface mainly during the early stage of etching. With the longer etching the pronounced surface roughness was revealed in the form of microcavities. The plasma treatment increased significantly the polar component of surface free energy of the epoxy and produced low surface roughness. The physicochemical changes of the epoxy combined with the experimental adhesion results indicated that in the case of the electroless deposition the mechanical interlocking was the main adhesion mechanism. Sputter-deposited copper exhibited the highest pull strengths on the epoxy when the plasma pretreatment with oxygen was employed. The enhancement of the surface polarity of the epoxy and the enlarged surface contact area due to the increased roughness were the most important factors in the adhesion.     

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。     

碳纤维的表面处理

本文综述了碳纤维的表面结构与性能 ,介绍了两种通用的碳纤维表面处理方法 :电化学氧化法和等离子氧化法 ;同时也总结了碳纤维表面处理对提高碳纤维 /树脂复合材料界面的粘接机理。     

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。      

Influence of surface treatment on adhesion of polyethylene fibres

Abstract

A detailed examination has been undertaken of the influence of surface treatment on the adhesion of polyethylene fibres to epoxy resin. The pull-out adhesion has been determined for untreated, chromic acid treated, and plasma etched monofilaments with different draw ratios and thermal annealing treatments. In a few cases, additional chemical treatments were applied to plasma treated fibres before the pull-out test. The polyethylene surface energy also has been determined by measurement of contact angle. The results, taken together, suggest that the adhesion depends on three factors: (i) the wettability (or physicochemical interactions), which is affected by the extent and nature of the surface treatment as well as the fibre draw ratio; (ii) the surface roughness, after plasma etching only, where a honeycomb structure of pits permits mechanical keying between the fibre and the resin (this structure has been examined by scanning electron microscopy); and (iii) the number of chemical bonds per unit area between the fibre and the resin. It is concluded that these three factors can be regarded as additive and that optimum results are obtained when their respective pull-out strengths reach their maximum values, ~2, ~3, and ~1·7 MN m^?2.

MST/640     

DEPOSITION OF DIAMOND FOR CUTTING TOOL APPLICATIONS

The poor adhesion of diamond film to substrates is one of the major problems for practical use in a cutting tool (1-4). in this study, sintered tungsten carbide (WC) body without Co metal, not cemented carbide, was used as the substrate (5), and the effects of surface decarburization of the substrate for improvement in the adhesion of diamond films were investigated. The surface decarburization and diamond coating were carried out in a microwave plasma CVD system. From the results of several adhesion tests, including the cutting tests, it is concluded that the good adhesion is obtained by surface decarburization of the substrate before diamond coating. The reasons for improvement in adhesion are considered by observing the interface structure between the film and the substrate. The damage mechanism of diamond coating on cutting an AI-18%Si alloy with increasing cutting speed is also discussed.     

Effects of plasma oxidation on the surface and interfacial properties of ultra-high modulus carbon fibres

An ultra-high modulus (UHM) carbon fibre was submitted to an oxygen plasma treatment. The effects of this treatment on the physical and chemical properties of the carbon surfaces were investigated by using surface characterisation techniques. SEM and STM studies were performed in order to determine the changes in the surface morphology. Observations on the nanometre scale lead to the conclusion that the plasma oxidation “cleaned” the original surfaces of carbonaceous impurities. XPS analysis of the treated fibres revealed a very significant increase of oxygen content. Single-fibre epoxy composites were prepared from as-received and plasma-treated fibres, and fragmentation tests were performed in order to characterise fibre/matrix interfacial adhesion. Raman spectroscopy has been used to map the strain along the fibre during tensile loading of the matrix, and the distribution of interfacial shear stress has been obtained. The quality of the interface improved dramatically after the surface treatment, supporting the ability of cold plasma oxidation to enhance the adhesion of UHM carbon to epoxy matrices. It is concluded that the increase of the oxygen surface content and the removing of the outermost layers may contribute in a co-operative way to the improvement on fibre/matrix adhesion.     

An Improvement on Adhesion of Sputtered TiC Coating to Steel Substrate

Introducing N_2 during sputtering andpre-oxidation of substrate were investigatedto improve the adhesion of sputtered TiC coatingto steel substrate. The results show thatyeactive gas N_2 increases the adhesion of TiCcoating to steel because of a graded interfaceexisting between coating and substrate. Theinteraction of discharge plasma with the surfaceof substrate was discussed. Pre-oxidation ofsubstrate is effective for improving the adhesiondue to the fomation of FeTi0_3 which appearedas an inteylayer between coating and pre-oxidizedsubstrate.