化学气相沉积PPy/UHMWPE纤维的研究

采用化学气相沉积制备了聚吡咯/超高相对分子质量聚乙烯(PPy/UHMWPE)纤维,测试了不同氧化剂浓度、不同沉积时间和温度下PPy/UHMWPE纤维的表面剪切强度,用扫描电镜、动态热机械分析仪、傅立叶变换红外光谱仪分析了PPy/UHMWPE纤维的表面形态、热机械性能和复合材料官能团的变化。结果表明:PPy均匀分布在UHMWPE纤维表面,UHMWPE纤维与PPy之间无化学键作用而是分子间作用力;随着氧化剂三氯化铁浓度的增加和吡咯沉积时间的延长,PPy/UHMWPE纤维表面剪切强度先增大后减小;随着处理温度的升高,PPy/UHMWPE纤维表面剪切强度先增大,当处理温度超过85℃时,其剪切强度则减小。     

聚吡咯／聚偏氟乙烯纳米纤维复合电阻型薄膜气敏元件及其制作方法

本发明公开了聚吡咯／聚偏氟乙烯纳米纤维复合电阻型薄膜气敏元件及其制作方法。采用静电纺丝法在具有金叉指的陶瓷基体电极上沉积聚偏氟乙烯纳米纤维,然后通过气相原位聚合在其上复合聚苯胺得到聚吡咯／聚偏氟乙烯纳米纤维复合气体敏感薄膜。本发明制备工艺简单,成本低,‘尤其适用于批量生产。     

聚烯烃纤维

<正>20141135吡咯沉积聚合技术对UHMWPE纤维性能的影响Wang Wenyu…;Advanced Materials Research,2012,476～478(Pt.2),p.1374(英)在这篇论文中,将两种沉积聚合技术如气相和液相吡咯沉积聚合应用于超高分子质量聚乙烯(UHMWPE)纤维。讨论了沉积技术对纤维表面形态、力学性能、电稳定性以及表面粗糙度的影响。结果表明,沉积技术对UHMWPE纤维的性能有显著影响。经气相沉积聚合处理的纤维具有更细更小的     

聚吡咯／粘胶导电复合纤维的原位聚合法制备

用较简便的液相原位聚合法制备了聚吡咯／粘胶导电复合纤维、讨论了吡咯、氧化剂和介质酸浓度、反应温度和反应时间对纤维导电性能的影响，并采用气相色谱法研究了吡咯聚合反应动力学。结果表明，该导电复合纤维具有良好的导电性、力学性能和环境稳定性，扫描电（ＳＥＭ）结果表明聚吡咯均匀地复合在每单根纤维上。     

聚吡咯/CaSnO3锂电池负极材料的研制和应用

采用软化学方法制备出CaSnO3立方晶体,接着将其放入等离子体增强化学气相积淀仪(PECVD)进行吡咯气体辉光放电,使等离子体聚吡咯(PPy)沉积在CaSnO3表面上,获得PPy/CaSnO3复合材料.采用傅里叶转换红外光谱对其化学结构进行表征;利用X射线衍射仪和场发射扫描电子显微镜对CaSnO3改性前后的晶格结构和几...     

导电聚吡咯／聚酯复合织物研究

采用吡咯气固相沉积聚合法制备导电聚吡咯／聚酯复合织物，研究了处理工艺对聚酯织物结构与性能的影响。结果表明，聚酯织物先经碱减量处理60 min，再经1.0 mol／L氧化剂处理30 min，吡咯单体气固相沉积聚合8次可制得具有较好导电性能的聚吡咯聚酯复合织物，其表面电阻约为330 Ω／cm，其力学性能的降低程度不大，聚吡咯均匀致密地沉积在聚酯织物表面。     

聚吡咯层对碳纤维/环氧树脂复合材料界面粘结性能的影响

以三氯化铁为氧化剂,采用吡咯液相沉积聚合方法制备聚吡咯-碳纤维(PPy-CF),然后与环氧树脂(EP)复合,制得PPy-CF/EP复合材料,并对其进行拉伸性能测试,研究了聚合温度对PPy-CF/EP复合材料界面剪切强度(IFSS)的影响。结果表明:在CF表面吡咯沉积聚合最佳工艺条件为聚合温度70℃,时间30min,经过吡咯沉积聚合改性后,得到的PPy-CF/EP复合材料的IFSS有所提高;最佳条件下制得的PPy-CF/EP复合材料的IFSS是CF/EP复合材料的1.24倍;在PPy-CF中,PPy与CF之间无化学键作用,PPy-CF/EP复合材料的IFSS与PPy-CF表面含氧基团和粗糙度有关;吡咯化学沉积聚合改性是一种提高纤维与树脂界面粘结性能的有效方法。     

高强力聚乙烯复合材料之界面特性评估

商业化之ＳＰＥＣＴＲＡ纤维因具有高度伸展链之聚乙烯化学结构，故为高强度及高模数之高性能纤维。但此纤维仍有低熔点、潜变及界面性差之缺点，故尚未广泛应用于复合材料上。本研究尝试以化学氧化合聚吡咯（ＰＰｙ）之界面处理，来改善高强力聚乙烯纤维之界面性。并经由界面拉拔试验及表面电位的评估，以建立界面剪断力与表面电位之关连性。实验上将ＳＰＥＣＴＲＡ纤维分别在不同温度条件下，经ＰＰｙ以化学氧化处理，并将经ＰＰｙ     

铁催化薄膜的微观结构对碳纳米管阵列生长的影响

原文节录：碳纳米管具有高的杨氏模量，高的长径比及独特的电学性能，尤其是优异的场发射性能，足下一代场发射显示器理想的候选材料之一。目前制备碳纳米管的方法主要有电弧放电法、激光烧蚀法、化学气相沉积法等。但由于前两种方法操作工艺很难控制，难以实现大批量生产，而且制备的碳纳米管粗产品还需进一步纯化处理，从而限制了其发展。而化学气相沉积法操作简单，易于控制及容易实现批量生产等优点，口前被广泛用于碳纳米管的制备。化学气相沉积法又分为微波等离子增强化学气相沉积法、热化学气相沉积法、热丝化学气相沉积法及电子回旋共振化学气相沉积法等。     

聚吡咯/钯中空胶囊的制备及其催化性研究

以单分散的聚苯乙烯为模板,经过一段时间的磺化处理,并使吡咯单体在其表面发生聚合,最终形成导电聚吡咯/聚苯乙烯复合物;同样以单分散的聚苯乙烯为模板,在其表面包覆聚吡咯后,形成的聚吡咯复合物经过溶剂的刻蚀,去除了聚苯乙烯结构,形成聚吡咯中空胶囊,并使用还原剂在其表面负载沉积钯纳米粒子,最终得到的聚吡咯/钯中空胶囊,并对其催化性进行研究。结果表明,这种复合材料在以硼氢化钠为还原剂还原亚甲基蓝的反应中展现了良好的催化活性。     

铬酸处理的超高分子量聚乙烯纤维粘接性研究

本文采用不同浓度和温度下的铬酸溶液对超高分子量聚乙烯纤维进行表面处理。通过DSC、DMA、X-衍射和SEM分析纤维的结构,测试了纤维接触角、断裂强度和层间剪切强度。实验结果表明,随着处理液酸浓度的增加,纤维表面刻蚀程度增加,层间剪切强度增大,而纤维表面极性不变;处理时间和溶液温度须控制在一个合适的水平。     

Surface modification of UHMWPE fibers

Ultrahigh molecular weight polyethylene (UHMWPE) fibers have a high specific strength, high specific modulus, and outstanding toughness, but their poor adhesive properties has limited their use for composite material applications. In this research, the effects of chemical etching on the surface chemistry and topography have been explored using chromic acid, potassium permanganate, and hydrogen peroxide etching. The smooth surface observed on the as-received fiber was rich in ether and/or hydroxyl oxygen. This smooth surface resulted from the presence of an outer layer, a weak boundary layer, that was removed by all the etchants. A fibrillar structural hierarchy was revealed beneath this outer layer and the fiber was relatively unchanged by further etching. Chromic acid, the strongest etchant studied, produced a rough and oxidized UHMWPE surface with both ether and carbonyl oxygen. The combination of outer layer removal, roughness, and changes in oxygen bonding helps explain the improved adhesion on chromic acid etching in spite of the reduction in surface oxygen. Neither hydrogen peroxide nor potassium permanganate etching roughened or oxidized the surface to a great extent and neither yielded improved adhesion. © 1994 John Wiley & Sons, Inc.     

Mechanical properties of surface‐modified ultra‐high molecular weight polyethylene fiber reinforced natural rubber composites

The mechanical properties of ultra‐high molecular weight polyethylene (UHMWPE) fibers reinforced natural rubber (NR) composites were determined, and the effects of fiber surface treatment and fiber mass fraction on the mechanical properties of the composites were investigated. Chromic acid was used to modify the UHMWPE fibers, and the results showed that the surface roughness and the oxygen‐containing groups on the surface of the fibers could be effectively increased. The NR matrix composites were prepared with as‐received and chromic acid treated UHMWPE fibers added 0–6 wt%. The treated UHMWPE fibers increased the elongation at break, tear strength, and hardness of the NR composites, especially the tensile stress at a given elongation, but reduced the tensile strength. The elongation at break increased markedly with increasing fiber mass fraction, attained maximum values at 3.0 wt%, and then decreased. The tear strength and hardness exhibited continuous increase with increasing the fiber content. Several microfibrillations between the fiber and NR matrix were observed from SEM images of the fractured surfaces of the treated UHMWPE fibers/NR composites, which meant that the interfacial adhesion strength was improved. POLYM. COMPOS., 38:1215–1220, 2017. © 2015 Society of Plastics Engineers     

Radiation‐induced graft copolymerization of MMA monomer onto UHMWPE: Adhesion improvement

Graft copolymerization of methyl methacrylate monomer onto ultra high molecular weight polyethylene (UHMWPE) and acid‐etched UHMWPE was conducted using preirradiation method in air in the presence of a Mohr salt and sulfuric acid to improve adhesion to the bone cement. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, gravimetric method, goniometry, and interfacial bonding strength measurements. The FTIR results showed the presence of ether, carbonyl, and hydroxyl groups for grafted films. The gravimetric results showed that the chromic acid etching and graft copolymerization had a synergetic effect so, the irradiated, then chromic acid etched at room temperature and grafted sample (Rad etch25) had the highest grafting degree. The interfacial bonding strength between UHMWPE and poly methyl methacrylate bone cement was considerably improved by graft copolymerization and chromic acid etching. The surface morphology was studied by scanning electron microscopy. The substitution of polar groups into the backbone of UHMWPE by chromic acid etching and graft copolymerization changed its contact angles with water and methylene iodide and increased its surface energy, as evidenced by contact angle measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface modification of ultra‐high‐molecular‐weight polyethylene. II. Effect on the physicomechanical and tribological properties of ultra‐high‐molecular‐weight polyethylene/poly(ethylene terephthalate) composites

We performed surface modification of ultra‐high‐molecular‐weight polyethylene (UHMWPE) through chromic acid etching, with the aim of improving the performance of its composites with poly(ethylene terephthalate) (PET) fibers. In this article, we report on the morphology and physicomechanical and tribological properties of modified UHMWPE/PET composites. Composites containing chemically modified UHMWPE had higher impact properties than those based on unmodified UHMWPE because of improved interfacial bonding between the polymer matrix and the fibers and better dispersion of the fibers within the modified UHMWPE matrix. Chemical modification of UHMWPE before the introduction of PET fibers resulted in composites exhibiting improved wear resistance compared to the base material and compared to unmodified UHMWPE/PET composites. On the basis of the morphological studies of worn samples, microploughing and fatigue failure associated with microcracking were identified as the principle wear mechanisms. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Dynamic mechanical properties of the chemical oxidation on UHMWPE fibers for improved adhesion to epoxy resin matrix

The improved adhesion of an ultrahigh molecular weight polyethylene (UHMWPE) fiber to an epoxy from applying polypyrrole (PPy) was investigated using chemical oxidation polymerization. The interfacial shear strength of the PPy-treated fiber/epoxy was enhanced by 280%. Such an improvement was verified in the previous research using a pull-out test. Dynamic mechanical analysis (DMA) and a morphological examination were performed to evaluate the characteristics of the molecular motions of the UHMWPE fiber/PPy/epoxy composites. Two composite materials, a UHMWPE fiber/PPy and a UHMWPE fiber/PPy/epoxy, were tested by DMA. The results show that both the α_c transitions of the PPy-treated fibers and its composites shift toward higher temperature. In the SEM photos of the UHMWPE fiber/PPy, a very clear roughening effect on the surface of PPy-treated UHMWPE fiber was also observed, which contributes much to the modification of the interface to the epoxy. The results show that an adhesion improvement mechanism for the PPy-treaded UHMWPE fiber is due to the surface roughening effect and the intermolecular interaction. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1387–1395, 1998     

Irradiation grafting of methyl methacrylate monomer onto ultra‐high‐molecular‐weight polyethylene: An experimental design approach for improving adhesion to bone cement

The grafting of methyl methacrylate (MMA) onto ultra‐high‐molecular‐weight polyethylene (UHMWPE) and chromic acid etched UHMWPE was conducted with a preirradiation method in air in the presence of a Mohr salt and sulfuric acid. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, a gravimetric method, differential scanning calorimetry, scanning electron microscopy (SEM), and interfacial bonding strength measurements. The FTIR results showed the presence of ether and carbonyl groups in the MMA‐grafted UHMWPE (MMA‐g‐UHMWPE) samples. The Taguchi experimental design method was used to find the best degree of grafting (DG) and bonding strength. The efficient levels for different variables were calculated with an analysis of variance of the results. SEM micrographs of MMA‐g‐UHMWPE samples showed that with increasing DG and chromic acid etching, the MMA‐g‐UHMWPE rich phase increased on the surface; this confirmed the high interfacial bonding strength of the grafted samples with bone cement. The grafting of the MMA units onto UHMWPE resulted in a lower crystallinity, and the crystallization process proceeded at a higher rate for the MMA‐g‐UHMWPE samples compared to the initial UHMWPE; this suggested that the MMA grafted units acted as nucleating agents for the crystallization of UHMWPE. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Surface modification of ultra‐high‐molecular‐weight polyethylene. I. Characterization and sintering studies

We performed surface modification of ultra‐high‐molecular‐weight polyethylene (UHMWPE) through chromic acid etching with the aim of improving the performance of UHMWPE's composites with poly(ethylene terephthalate) fibers. In part I of this study, we evaluated the effects of chemical modification on the surface properties of UHMWPE with X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements. The thermal properties, rheology, and sintering behavior of the modified UHMWPE were compared to those of the base material. XPS and FTIR analysis confirmed the presence of carboxyl and hydroxyl groups on the surface of the modified powders. The substitution of polar groups into the backbone of the polymer decreased its contact angles with water and hexadecane and increased its surface energy, as evidenced by contact angle measurements. The modified UHMWPE was more crystalline than the base resin and less prone to thermal degradation. Although the rheological properties were virtually identical, the modified powders sintered more readily, presumably due to their higher surface energy, which suggested enhanced processability by compression molding. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Chemical modification combined with corona treatment of UHMWPE fibers and their adhesion to vinylester resin

The influence of corona treatment on the near-surface structures of treated ultra-high-molecular-weight polyethylene (UHMWPE) fibers was studied first by atomic force microscopy (AFM). AFM pictures showed that the pits on the corona-treated PE fiber surfaces had different change characteristics in depth compared with in length and breadth with variations of corona power. Then the UHMWPE fibers were subjected to chemical modification following the corona treatment, named the two-stage treatment. Surface morphologies and chemical properties of the treated fibers were analyzed by scanning electron microscopy (SEM), FT-IR–ATR spectroscopy and Raman spectroscopy. The results obtained suggested that some carbon–carbon double bonds had been introduced on the surfaces of the PE fibers after the two-stage treatment. These unsaturated groups could participate in free-radical curing of vinylester resin (VER), and this resulted in improvement of interfacial adhesion strength in the PE fiber/VER composites. In addition, the mechanical properties of the UHMWPE fibers reduced after corona treatment did not reduce further after subsequent chemical treatment with increase of corona power. In short, the two-stage treatment proved to be effective in improving the interfacial adhesion of the composites and maintaining the high mechanical properties of the PE fibers, as this treatment method did not destroy the bulk structure of the UHMWPE fibers.