芳纶表面改性技术进展(一)——物理改性方法

简单介绍了芳纶Ⅱ、芳纶Ⅲ及Technora 3种对位芳纶,并对芳纶表面改性的物理方法进行了概述。综合论述了表面涂层技术、等离子体技术、超声波技术、γ-射线技术在芳纶表面改性过程中的应用过程、反应原理及改性效果。结合应用实践,对相关物理改性技术的应用进行了探讨和展望。     

对位芳香族聚酰胺纤维及其增强复合材料的发展

介绍了对位芳香族聚酰胺纤维(对位芳纶)特别是聚对苯二甲酰对苯二胺纤维的国内外发展情况,包括纤维品种、产量、性能和该类纤维作为先进复合材料骨架的发展情况。指出我国发展包括芳纶Ⅲ在内的对位芳纶产业的必要性和紧迫性,以及芳纶表面改性、树脂基体及增强复合材料的研究重点和方向。     

对位芳纶表面改性的最新研究进展

介绍了聚对苯二甲酰对苯二胺纤维(又称对位芳纶)的表面改性技术及其研究进展。对位芳纶的表面改性方法分为物理改性和化学改性,其中,化学改性包括表面刻蚀、表面接枝、共聚改性等方法,物理改性包括等离子体处理、表面涂层、γ射线辐射、超声浸渍处理、紫外辐照等方法。指出了对位芳纶表面改性的未来发展方向是实现无损改性和工业化在线处理。     

多巴胺改性对位芳纶浆粕及其增强橡胶复合材料的性能研究

利用多巴胺氧化自聚合可形成一层薄的强黏性复合层的特性,对聚对苯二甲酰对苯二胺(PPTA,对位芳纶)浆粕(AP)表面进行改性修饰,并对改性后的芳纶浆粕进行了X射线光电子能谱、扫描电子显微镜、热失重分析等表征。进一步以丁腈橡胶(NBR)为基体,研究了不同浓度多巴胺浸渍液处理的改性芳纶浆粕及其含量对增强NBR复合材料力学性能的影响。结果表明,聚多巴胺成功附着在AP表面,并在浸渍液质量浓度2.0 g/L、浸渍时间24 h的实验条件下,改性效果最佳。改性芳纶浆粕的热性能与改性前相比稍有所下降,但仍具有良好的热稳定性能。改性后AP与NBR界面黏结性能有所改善,并显著提高了复合材料的力学性能。     

芳纶及其复合材料的制备技术及应用进展

介绍了对位芳香族聚酰胺纤维(简称对位芳纶)、间位芳香族聚酰胺纤维(简称间位芳纶)、带有杂环结构的三元共聚聚酰胺纤维(芳纶Ⅲ)的制备工艺及性能特点;概述了国内外芳纶的发展概况,我国对位芳纶、间位芳纶、芳纶Ⅲ及其复合材料的研究进展;阐述了芳纶在航空航天领域、军事和个体防护装备领域、建筑领域、电子电器材料领域、橡胶工业、环保领域的应用;指出今后我国对位芳纶的研究在其高聚物制备和纺丝技术上还需进一步提升;芳纶增强复合材料中,对于芳纶表面改性技术尚处于实验室阶段,实现大批量工业化生产,以及表面改性效果的持久性仍有待于进一步研究。     

对位芳纶纤维的多巴胺仿生修饰及硅烷偶联剂二次功能化

研究采用多巴胺仿生修饰和硅烷偶联剂二次功能化的新方法对对位芳纶纤维进行表面改性。多巴胺首先氧化自聚,形成聚多巴胺包覆在纤维表面,以提供功能化平台。二次功能化硅烷偶联剂单体接枝到纤维表面的聚多巴胺层,在纤维表面引入有助于提高粘合性能的表面官能团。整个表面改性过程简单,无毒和可控。表面改性后的对位芳纶纤维/橡胶复合材料的H抽出力提高了69%,高温老化后粘合力保持率也显著提升。     

改性膨胀石墨对甲醛的吸附性能研究

对含甲醛的废气处理一般采用吸附法，本文以天然鳞片石墨、浓硫酸、浓硝酸、双氧水、重铬酸钾为原料，采用改进的二次氧化法制备膨胀石墨，并对所制得的膨胀石墨进行表面改性。运用改性后的膨胀石墨对甲醛进行静态和动态吸附实验，实验结果表明，改性后的膨胀石墨对甲醛气体的吸附能力有大幅度提高。研究了改性前后膨胀石墨孔结构的变化及其对饱和吸附量的影响，并对改性机理进行了初步探讨。     

对位芳纶结构对其浆粕性能的影响

采用黏度法、X射线衍射法、光学显微镜及扫描电镜、差示扫描量热等手段对对位芳纶短纤维的分子结构、相对分子质量(MW)、聚集态结构、表面形貌结构和热性能进行了研究;采用槽式打浆机对对位芳纶进行打浆制得对位芳纶浆粕,探讨对位芳纶的结构对其浆粕化工艺及浆粕性能的影响。结果表明:对于特性黏数为1.80~3.97 dL/g的对位芳纶,其MW为(1.29~2.72)×104,结晶度为46.51%~57.10%,最大失重率为37.74%~46.90%;对位芳纶表面光滑,纤维呈刚性伸直状,MW大的芳纶,其纤维表面分丝帚化;MW和结晶度是影响对位芳纶强度、浆粕化工艺以及浆粕性能的重要因素,在制备对位芳纶浆粕时,应选择MW大于2×104,作用力大于纤维内部的次价力而小于主价力,在保证纤维长度的情况下,作用力越大,分丝帚化效果越好。     

芳纶纤维的表面改性及增强高分子复合材料的研究进展

介绍了芳纶纤维的表面改性技术进展,及其在高分子复合材料中的应用效果,对表面涂覆、表面辐照、等离子体、表面氧化、表面接枝等物理或化学的芳纶纤维表面改性方法的原理和实施效果进行了重点描述,对芳纶纤维的表面改性技术的现状进行了评述。兼顾环境友好、纤维损伤小、高表面活化的高效和环保的表面改性技术的复合化是芳纶纤维表面改性技术的发展趋势。     

光电缆用高膨胀率对位芳纶阻水纱的研制

对位芳纶阻水纱属于高端芳纶产品,主要用于光电缆中起阻水及加强作用。首先合成吸水树脂胶液,然后通过芳纶阻水纱DOE试验设计及响应曲面分析,得到最优模型式,回归模型对试验数据拟合程度良好;之后通过响应曲面优化,得到优化后的试验参数;最后对优化后的试验条件进行验证。将制得的对位芳纶阻水纱与市售阻水纱进行对比,结果显示自制对位芳纶阻水纱吸水膨胀率优于市售产品,为后续国产芳纶阻水纱批量化生产积累了经验数据。     

高锰酸钾对芳纶的表面改性研究

利用高锰酸钾在强酸性条件下具有氧化性的特性对芳纶进行表面改性,采用正交实验探讨了硫酸浓度、高锰酸钾含量、处理温度和处理时间对芳纶力学性能的影响,采用扫描电子显微镜和生物显微镜观察处理前后芳纶的表面形貌。结果表明:最优工艺为硫酸质量分数10%,高锰酸钾浓度5g/L,处理温度为30℃,处理时间35min。改性后的芳纶强度损失不大,表面产生线状刻蚀,粗糙度提高。     

芳纶表面改性技术进展(二)——化学改性方法

对芳纶表面改性的化学方法进行了概述。论述了表面刻蚀技术、表面接枝技术在芳纶表面改性过程中的应用过程、反应原理、改性效果,对化学改性技术的优缺点进行了分析,指出了其进一步的发展趋势。     

Improving Interfacial and Compressive Properties of Aramid by Synchronously Grafting and Crosslinking

Improving compressive strength of aramid and its adhesion to resin is of great significance for its application in reinforcing materials. In this study, a novel method for improving interfacial and compressive properties of aramid fiber is presented. α,α′‐Dichloro‐p‐xylene (DCX) is utilized as an external crosslinker to modify aramid fiber containing benzimidazole units during the post swelling process. Chloromethyl groups from DCX can react with benzimidazole moieties of the aramid fiber. The reaction can be regarded as crosslinking inside the fiber and grafting on the surface. By controlling the swelling effect of the solvent during modification, bulk crosslinking degree and surface grafting density can be adjusted. Therefore, intermolecular interaction and surface polarity of the aramid fiber can be improved simultaneously. After modification, the compressive strength of the fiber can be enhanced by nearly 100% and interfacial shear strength increases by 37%, while excellent mechanical properties are maintained. Therefore, comprehensive performance of aramid fiber can be improved significantly by synchronously crosslinking and grafting.     

硅烷偶联剂改性芳纶的性能测试

采用硅烷偶联剂对芳纶进行改性,然后用傅里叶红外光谱仪、单一纤维接触角测试仪和X射线衍射仪对改性前后的芳纶进行测试、观察并分析。结果显示:红外光谱分析表明芳纶的改性发生在纤维的表面,并没有对纤维大分子产生明显破坏;接触角测试表明改性后芳纶的接触角变小,说明KH550硅烷偶联剂可改善芳纶的亲水性;X射线衍射测试表明芳纶结晶度有所下降,可以更好地与树脂黏结。     

Argon low‐temperature plasma modification of chopped aramid fiber and its effect on paper performance of aramid sheets

Chopped aramid fiber was modified by an argon low‐temperature plasma treatment to enhance the interfacial strength of aramid paper. The water contact angle of the aramid fiber and the tensile strength, tearing strength, and evenness of the aramid sheets were investigated under different conditions, and the parameters of the argon low‐temperature plasma modification, like gas pressure, discharge power, and discharge time, were optimized. The chemical structure and surface morphology of the fiber after plasma modification were characterized by X‐ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. The strengthening mechanism of aramid paper by low‐temperature plasma modification was also studied. It was found that the argon low‐temperature plasma treatment introduced some new polar groups onto the fiber surface and increased the fiber surface wettability and roughness. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45215.     

介质阻挡放电在芳纶表面改性中的应用

综述了介质阻挡放电应用于芳纶表面改性研究的最新进展;介绍了介质阻挡放电的机理、特点以及国内主要的介质阻挡放电等离子体的设备;阐述了介质阻挡放电对芳纶亲水性能和粘结性能等表面性能的改善。指出芳纶等离子体表面改性的时间效应限制了其广泛应用,应进一步加强纤维表面等离子体改性的机理研究。     

低温等离子体改性芳纶1414的研究

对芳纶1414进行低温等离子体表面改性以改善其构成复合材料时的界面黏结性能。设计正交试验,得到低温等离子体处理芳纶1414的最佳条件为放电功率100 W,处理时间300 s,放电压强20 Pa。采用电子单纤维强力机、纤维摩擦因数测定仪、纤维接触角测量仪、扫描电子显微镜和傅里叶变换红外光谱仪对改性前后的芳纶1414进行性能表征。结果表明:经过低温等离子体改性的芳纶1414的断裂强力较原样下降了6.3%,静摩擦因数上升了15.7%,表面接触角减小了36.8%,纤维表面出现微小均匀的凹槽,增大了比表面积,引入了自由基团,增大了表面反应活性,从而改善了与树脂基体复合时的黏结强度。     

RETRACTED ARTICLE: Surface modification of aramid fibers with novel chemical approach

Friedel–Crafts Reaction as a simple and convenient approach to the surface modification of aramid fiber was introduced in this paper. Epoxy chloropropane was chosen as the treatment reagent to modify aramid fibers surface via Graft reaction. After the modification, the interfacial properties of aramid/epoxy composites were investigated by the single fiber pull-out test (SFP), and the mechanical properties of aramid fibers were investigated by the tensile strength test. The results showed that the interfacial shear strength (IFSS) value of aramid/epoxy composites was enhanced by about 50%, and the tensile strength of aramid fibers had no obvious damage. The crystalline state of aramid fibers was determined by X-ray diffraction instrument (XRD), and the results showed that there were not any distinct crystal type varieties. The surface elements of aramid fibers were determined by X-ray photoelectron spectroscopy (XPS), the analysis of which showed that the oxygen/carbon ratio of aramid fiber surface increased obviously. The possible changes of the chemical structure of aramid fibers were investigated via Fourier transform infrared spectrum (FTIR), and the analysis of which showed that the epoxy functional groups were grafted into the molecule structure of aramid fibers. The surface morphology of aramid fibers was analyzed by Scanning electron microscope (SEM), and the SEM results showed that the physical structure of aramid fibers was not etched or damaged obviously. The surface energy of aramid fibers was investigated via the dynamic capillary method, and the results showed that the surface energy was enhanced by 31.5%, and then the wettability degree of aramid fiber surface was enhanced obviously too. All of the results indicated that this novel chemical modification approach not only can improve the interfacial bonding strength of aramid/epoxy composites remarkably, but also have no negative influence on the intrinsic tensile strength of aramid fibers.     

芳纶的发展现状及其表面改性研究进展

芳纶以密度小、高模量、高强度等多种优异性能被广泛应用,而纤维表面改性和功能化研究是实现其高附加值利用的基础.介绍了芳纶的发展历史和现状,总结了芳纶的分类和性质,并详细阐述了芳纶表面改性的主要方法以及最新研究成果,希望为后续的研究提供新的思路.