芳纶纤维／环氧树脂微复合材料的界面断裂

本文采用空气冷等离子体改性Ｋｅｖｌａｒ－４９表面。通过单丝拔出实验研究表明经过纤维表面改性改善了芳纶纤维／环氧树脂的界面结合情况；芳纶纤维／环氧树脂微复合材料￣ａ）的破坏有两种类型：破坏发生在界面和纤维的内聚破坏。     

芳纶纤维／环氧树脂微复合材料的界面断裂

本文采用空气冷等离子体改性Ｋｅｖｌａｒ－４９表面。通过单丝拔出实验研究表明经过纤维表面改性改善了芳纶，纤维／氧化树脂的界面结合情况，芳纶纤维／环氧树脂微复合材料的破坏有两种类型，破坏发生在界面和纤维的内聚破坏。     

单丝拔出实验研究芳纶－环氧树脂界面相

用单丝拔出实验研究了以有机硅表面处理剂处理的Ｋｅｖｌａｒ－４９－环氧树脂体系界面相。从力一位移曲线可得到界面破坏强度、界面破坏能、界面摩擦功等界面参数。硅表面处理剂对三者的贡献不同，以２￣＃处理剂处理的综合效果最好。     

纤维束动态拉伸力学性能的实验研究

对Ｐｏｌｙｖｉｎｙ－ａｌｃｏｈｏｌ（ＰＶＡ），Ｅ－ｇｌａｓｓ和Ｋｅｖｌａｒ４９纤维束的应变率相关性和能量吸收能力进行了对比，冲击拉伸实验结果表明，除ＰＶＡ纤维束的初始弹性模量外，三种纤维束的力学性能均具有应变率相关性，其中ＰＶＡ和Ｅ－ｇｌａｓｓ的应变率敏感性较Ｋｅｖｌａｒ４９强烈；Ｋｅｖｌａｒ４９的能量吸收能力高于ＰＶＡ并且明显优于Ｅ－ｇｌａｓｓ。     

DBM-g-PE与PVC的相互作用研究EI

采用固相接枝法制备了ＤＢＭ－ｇ－ＰＥ，用红外光谱分析证明了接枝物确实存在。ＰＶＣ／ＣＰＥ＝１００／５合金性能测定结果表明，添加５份接枝物的合金（Ａ），缺口冲击强度、拉伸强度分别为１８．２ｋＪ／ｍ２和５３．０ＭＰａ；而添加５份ＰＥ的合金（Ｂ），其相应性能为５．１ｋＪ／ｍ２和３３．８ＭＰａ。不加接枝物的合金（Ｃ），虽有高韧性，但拉伸强度却由５３．０ＭＰａ降至５０．２ＭＰａ。ＤＳＣ、ＳＥＭ的结果均表明，ＰＥ接枝ＤＢＭ后与ＰＶＣ的相互作用增强，与ＣＰＥ协同作用能增韧、增强ＰＶＣ，并探讨了其机理。     

Kevlar／PF尼龙Ⅱ^#复合体系的界面形态研究

用３种二酰氯和己内酰胺对Ｋｅｖｌａｒ进行了表面化学接枝。考察了纤维表面、结晶温度和基体ＰＦ尼龙Ⅱ＾＃（即石油发酵尼龙Ⅱ＾＃）的γ－辐照等因素对Ｋｅｖｌａｒ／ＰＦ尼龙界面形成横晶的影响。辛二酰氯能够最有效地提高Ｋｅｖｌａｒ诱发ＰＦ尼龙Ⅱ＾＃的结晶能力，其界面结晶形态还与结晶温度和基体的性质密切相关。     

高性能热塑性树脂增韧聚苯硫醚的韧性

研究了高性能热塑性树脂双酚Ａ型聚砜（ＰＳＦ）、酚酞型聚醚酮（ＰＥＫ－Ｃ）增韧聚苯硫（ＰＰＳ）的破坏韧性和破坏形态。实验表明：ＰＳＦ与ＰＥＫ－Ｃ两种材料的加入都能改善ＰＰＳ的冲击强度和破坏韧性。不同共混（加入）方法对ＰＳＦ／ＰＰＳ与ＰＥＫ／－Ｃ／ＰＰＳ两体系的增韧效果有效果。     

聚碳酸酯/聚乙烯相容性的研究

考察了聚碳酸酯与聚乙烯（ＰＣ／ＰＥ）及聚碳酸酯与马来酸酐接枝聚乙烯（ＰＣ／ＰＥ－ｇ－ＭＡＨ）共混体系的力学性能,研究了共混体系的相容性,研究表明,ＰＥ的加入有效地提高了ＰＣ的抗冲击性能,而ＰＣ／ＰＥ－ｇ－ＭＡＨ体系的力学性能及混溶性优于ＰＣ／ＰＥ体系。红外光谱表明,接枝ＰＥ与ＰＣ共混时,发生酯交换反应,冲击断口及样条截面的扫描电镜发现,ＰＣ／ＰＥ－ｇ－ＭＡＨ的相态分布均匀,两相之间存在一定的相互作     

PET／HDPE共混物的形态结构及力学性能的研究

利用ＩＲ、ＳＥＭ、ＤＳＣ和力学测试等分析方法，研究了熔融接枝高密度聚乙烯（ＨＤＰＥ－ｇ－ＭＡ）和界面改性剂（ＩＭ）对ＰＥＴ／ＨＤＰＥ共混物形态结构、界面偶联状况和力学性能的影响。结果在明，ＨＤＰＥ－ｇ－ＭＡ改善了ＰＥＴ与ＨＤＰＥ的相容性，使ＨＤＰＥ较均匀地分散在ＰＥＴ基体中，但并未检测到ＰＥＴ／ＨＤＰＥ－ｇ－ＭＡ界面有化学反应发生。界面改性剂的作用在于，一方面通过提高ＰＥＴ基体的粘度，并接近ＨＤＰＥ相的粘度而使分散相细化；另一方面通过与ＨＤＰＥ－ｇ－ＭＡ和ＰＥＴ的偶联反应而增强了ＰＥＴ／ＨＤＰＥ－ｇ－ＭＡ界面粘结，从而显著地提高了共混物的抗冲击性能。     

纤维诱发PF尼龙II^#的界面结晶效应研究

用偏光显微镜研究了３种纤维诱发ＰＦ尼龙Ⅱ＾＃（即石油发酵尼龙Ⅱ＾＃）界面结晶效应。结果表明，Ｋｅｖｌａｒ－４９（ＫＦ）、碳纤维（ＣＦ）和玻璃纤维（ＧＦ）均可诱发ＰＦ尼龙Ⅱ＾＃形成横晶；温度对纤维诱发ＰＦ尼龙界面结晶有一定影响。观察了应力及温度应力诱发ＰＦ尼龙结晶的特征。     

Analysis of the single-fibre pull-out test by means of Raman spectroscopy: Part II. Micromechanics of deformation for an aramid/epoxy system

The single-fibre pull-out test has been analysed for Kevlar-49 fibres in a cold-cured epoxy resin by using both a conventional pull-out experiment and Raman spectroscopy. The interfacial shear strength (ISS) has been estimated from the pull-out force for fibres with a range of embedded lengths. Raman spectroscopy has been used to analyse the distribution of fibre strain in the pull-out test by mapping the variation of strain along an aramid fibre undergoing pull-out from the epoxy resin matrix. At low strains the behaviour follows elastic shear-lag analysis but, as the fibre strain is increased, debonding takes place at the fibre/matrix interface. It is found that this debond propagates along the interface until the entire fibre is debonded. The fibre is then pulled out of the resin matrix by a frictional pull-out process. It is shown that the conventional pull-out experiment produces only an apparent value of ISS and that through a partial-debonding model it is possible to use the interfacial parameters obtained from the Raman analysis to predict the data from the conventional test.     

单丝拔出实验研究芳纶-环氧树脂界面相

用单丝拔出实验研究了以有机硅表面处理剂处理的Kevlar-49-环氧树脂体系界面相.从力一位移曲线可得到界面破坏强度、界面破坏能、界面摩擦功等界面参数.硅表面处理剂对三者的贡献不同,以2#处理剂处理的综合效果最好.     

Polyamide coating on carbon fibres and potential application in carbon/kevlar/epoxy hybrid composites

Hybrid unidirectional composite materials, consisting of alternately laminated layers of Kevlar-49 fibres and carbon fibres in an epoxy resin, have been studied. Before embedding, the carbon fibres were coated with a Nylon 6,6 film by an interfacial in-situ polymerization technique. Emphasis is given to the mechanical properties of the hybrid composites based on coated carbon, with those based on uncoated carbon, for various values of partial volume fraction of the carbon fibres, V_cf, polyamide content deposited on the carbon fibres, C_N, and total fibre (Kevlar + carbon) volume fraction, V_f.     

动态毛吸法测定纤维表面能

本文用浸润测定仪对玻璃纤维和Kevlar-49芳纶纤维进行了表面能测定,讨论了纤维束柱末端沾湿量的影响,提出了浸润仪测试数据的正确处理方法,求得了Kevlar-49纤维的表面能并对其色散分量和非色散分量进行了解析.     

Surface Modification of Aramid Fibres with Graphene Oxide for Interface Improvement in Composites

A novel method of biomimetic surface modification was used for aramid fibres aiming to enhance the interface properties between epoxy resin and the modified aramid fibre. Inspired by the composition of adhesive proteins in mussels, a thin layer of poly(dopamine) (PDA) was self-polymerized onto the surface of the aramid fibre. The graphene oxide (GO) was then grafted on the surface of PDA-coated aramid fibres. The microstructure and chemical characteristics of the pristine and modified fibres were characterised using Scanning Electron Microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), indicating successful grafting of GO on the PDA-coated aramid fibres. Single fibre tensile test and microbond test were carried out to evaluate the mechanical properties of the modified fibres. It was found that the fibre surface modification improved the interfacial shear strength by 210% and the fibre tensile strength was protected by GO-PDA coating.     

Surface properties and interfacial adhesion studies of aramid fibres modified by gas plasmas

The surface of aramid (Kevlar 49) fibre was modified by NH₃, O₂ or H₂O plasmas in order to improve the adhesion to epoxy resin. Electron spectroscopy for chemical analysis (ESCA) and static secondary ion mass spectroscopy (SSIMS) were used to identify the chemical compositions and functional groups of the plasma-treated fibre surface, respectively. The surface topography and mechanical properties of plasma-treated fibres were also investigated. After plasma treatments, the interfacial shear strength (IFSS) of aramid-fibre/epoxy-resin composites, as measured by the microbond pull-out technique, was markedly improved (43–83% improvement) and the fibre strength was only little affected (less than 10% loss). Significant improvement in the IFSS principally resulted from forming the covalent bonds between the newly reactive functionalities at the modified fibre surfaces and the epoxides of the resin.     

Plasma Modified Polyaramid Fiber Surface and Fiber/Epoxy Interface

Kevlar-49 fiber was surface-modified through cold air plasma treatment and plasma grafting ofacrylic acid (AA).Fiber surface properties were studied with ESCA,while interface properties with asingle fiber pull-out (SFPO) test.The stated surface modifications evidently improved the interfacialadhesion and increased the interfacial fracture energy of the aramid/epoxy composite system.     

Modification of properties of rayon fibre by graft copolymerization with acrylic monomers

The change in rayon fibre properties due the grafting polymerization of methyl metacrylate (MMA) and butyl acrylate (BA) was investigated. The formation of rayon-g-PMMA or PBA was confirmed by FTIR spectroscopy, X-ray analysis, and TGA. The adhesion to PMMA and epoxy resin matrixes was determined using the microdrop technique. The PBA or PMMA grafting on the fibre led to lower mechanical properties than the ungrafted rayon fibre. However, the grafted rayon had better thermal properties than the ungrafted rayon and a shift of the decomposition temperature of the rayon was observed. The PMMA grafted to rayon improved the interfacial adhesion when PMMA was used as matrix (microdrop technique). The grafted polymer (PBA or PMMA) restricted the “wetting” of the fibre when epoxy resin was used as matrix and lowering the adhesion in comparison with ungrafted rayon fibre.     

Fracture of Aramid Fiber/Epoxy Resin Micro Composites

Kevlar-49 fiber was modified through cold air plasma treatment and plasma grafting with acrylic monomers. Fracture of aramid fiber/epoxy resin micro composites has been studied by means of single fiber pull-out test. Tow types of pull-out curves are correlated with the different failure modes. A polyacrylic acid-co-ethyl acrylate graft layer can improve the adhesion and protect the fiber from damage caused by interfacial stresses.     

Synthesis and Characterization of High Performance Polymeric Hybrid Siliconized Epoxy Composites for Aerospace Applications

Two different types of hybridized siliconized epoxy matrix systems have been developed using two commercially available (CIBA-GEIGY) epoxy resins with hydroxyl terminated polydimethyl siloxane. The percentage siloxane content in the epoxy systems have been optimized based on the physico-chemical, electrical, mechanical and thermal properties. The matrix resins are cured using aliphatic amine (HY951), aromatic amine (HT972) and polyamidoamine (HY840) from CIBA-GEIGY and γ-aminopropyltriethoxysilane (A-186, Union Carbide). The optimized siliconized epoxy materials are filled with additives like fillers (SiO₂, BaSO₄ and TiO₂), plasticizer (dioctylphthalate), flame retardant (tris (2-chloropropyl) phosphate) and reinforced with E-glass fiber and Kevlar-49 and their effect on electrical and mechanical properties are studied. Introduction of siloxane units (silicone) in to the epoxy systems enhances dielectric properties with little loss of mechanical properties. Additives alter the electrical and mechanical characteristics based on their nature and concentration. Reinforcements enhanced the electrical and mechanical behavior to an appreciable extent. Data resulted from the studies reveal that the siliconized epoxy matrix systems reinforced with E-glass fiber and Kevlar-49 can be used in the filament wound liquid pressure vessels in the field of aerospace and other high performance engineering applications.