空气等离子体处理芳纶Ⅲ的性能研究

比较了国产芳纶Ⅲ与芳纶1414以及进口Twaron纤维的表面性能;采用空气等离子体处理技术对芳纶Ⅲ的表面进行改性,研究了空气等离子体处理工艺条件以及处理前后芳纶Ⅲ的结构与性能的变化。结果表明:国产芳纶Ⅲ的表面存在不均匀的浅沟槽,比芳纶1414和Twaron纤维表面粗糙,其表面浸润性较差,但却优于芳纶1414和Twaron纤维;空气等离子体处理芳纶Ⅲ的最佳条件为放电功率65 W,空气放电气压2 000 Pa,处理时间11 min,在此条件下处理的芳纶Ⅲ表面接触角由未处理时的55.8°降至41.5°,纤维的浸润性能得到改善,而其力学性能和大分子结构不受影响。     

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。     

氨气等离子体改性处理芳纶Ⅲ表面的研究

以氨气为反应气体,对芳纶Ⅲ进行等离子体表面改性处理,研究了等离子体处理时间和处理功率对纤维表面性能的影响;采用X射线光电子能谱、场发射扫描电镜、接触角和微脱粘实验等测试方法对改性前后纤维表面元素组成、形貌、润湿能力以及界面粘结强度进行表征。结果表明:芳纶Ⅲ经过氨气等离子体改性后,表面含氮极性基团的含量增加,粗糙程度增大,润湿能力得到明显的改善;当氨气等离子体处理时间为15 min,功率为100 W时,芳纶Ⅲ与环氧树脂的界面粘结强度从处理前的12.9 MPa提高到18.2 MPa,与水的接触角由处理前的71.4°下降到46.8°。     

DBD等离子体改性芳纶表面的动态工艺研究

采用介质阻挡放电(DBD)空气等离子体,选择不同放电强度及处理时间对芳纶表面进行连续动态处理。通过扫描电镜以及光电子能谱仪对处理前后芳纶表面进行表征。结果表明,经DBD等离子体处理后的芳纶表面粗糙度有较大提高,浸润性显著提高,且纤维表面C元素质量分数下降超过5%,0元素质量分数约上升8%;芳纶表面的粗糙度、浸润性及含氧基团含量均随放电强度和处理时间的增加而提高。     

空气等离子体处理芳纶纤维及其与天然橡胶/乳聚丁苯橡胶的黏合性能

考察了空气等离子体处理对芳纶纤维表面结构形态的影响,研究了空气等离子体和间苯二酚-甲醛-胶乳(RFL)浸胶处理芳纶纤维与天然橡胶(NR)/乳聚丁苯橡胶(ESBR)的黏合性能,并对经处理的芳纶纤维与NR/ESBR体系的界面层作了动态力学分析。结果表明,芳纶纤维经空气等离子体处理后,表面粗糙度增大,表面积增加,结晶度减小,但处理功率过大、处理时间过长时,芳纶纤维的表面又变得比较光滑、结晶度又呈增大趋势。随着等离子体处理时间的延长,芳纶纤维与NR/ESBR的黏合性能增强,但处理时间过长时,芳纶纤维与NR/ESBR的黏合性能下降;等离子体处理芳纶纤维经RFL进一步浸胶处理后,芳纶纤维与NR/ESBR的黏合性能大幅度提高。芳纶纤维与NR/ESBR的界面存在介于高模量芳纶纤维和低模量橡胶之间的过渡层。     

等离子体处理对芳纶性能的影响

芳纶作为增强材料在复合材料中有广泛的应用,其界面性能是影响其复合材料界面粘结性能的重要因素。分别采用H2、空气低温等离子体对芳纶表面进行了处理。研究了等离子体表面改性后芳纶性能的变化。结果表明:经低温等离子体处理后纤维表面张力增大,由46.0mN·m-1增加到63.2mN·m-1;表面极性增强,极性分数由58.0%提高到69.9%,而纤维单丝断裂强度未有明显变化。     

低温等离子体处理对芳纶/环氧界面性能的影响

在采用低温等离子体对芳纶纤维进行表面处理后，用扫描电镜观察处理前后的纤维表面，测试了纤维的拉伸性能，并用单纤维抽拔法对芳纶纤维／环氧树脂的界面性能做了定量的表征。实验结果表明：经低温等离子体处理后，芳纶纤维表面变得粗糙，拉伸强度随处理时间延长而下降，纤维初始模量和断裂伸长率略有下降，而芳纶／环氧界面的粘结强度有所提高。     

常压等离子体改善高性能纤维粘结性的研究

以氦气为载气,氧气为反应气体,对高强度聚乙烯和Twaron 1000芳纶两种高性能纤维进行常压等离子体处理,来改善纤维的粘结性能;采用单纤维抽拔实验测定等离子体处理前后纤维与环氧树脂之间的界面剪切力;利用原子力显微镜和X射线光电子能谱仪分析等离子体处理前后纤维表面形态和化学成分的变化。结果表明:高强度聚乙烯纤维和芳纶经常压等离子体处理后,纤维表面粗糙度增加,纤维表面碳元素含量下降,羟基、羧基等含氧或氮的极性基团增加,纤维粘结性能得到提高,但其强度无明显变化。     

芳纶纤维等离子体接枝改性处理研究

采用等离子体接枝对芳纶纤维表面进行改性处理,采用XPS、浸润性、界面剪切强度对等离子体接枝处理前后的表面组成、复合材料界面粘接性能等进行了研究,结果表明:等离子体接枝处理可以有效地提高芳纶纤维表面的极性官能团,增加与基体树脂-环氧树脂的浸润性,进而提高芳纶/环氧复合材料的界面粘接强度.     

芳纶纤维/AFR树脂复合材料界面粘结性能的研究

为了改善芳纶纤维复合材料的界面粘结性能,合成了一种新型树脂(AFR)作为基体,以未经任何表面处理的芳纶纤维作增强材料,制备了芳纶纤维/AFR复合材料。采用测定表面能、接触角、层间剪切强度、横向拉伸性能和扫描电镜观察形貌等方法,从宏观和微观等方面研究了芳纶纤维/AFR复合材料的界面粘结性能。结果表明,AFR树脂与芳纶纤维有相近的表面能,AFR树脂溶液与芳纶纤维的接触角为42.8°,而环氧树脂(EP)与芳纶纤维的接触角为68°,说明AFR树脂对芳纶纤维的润湿性优于EP树脂;芳纶/AFR复合材料的层间剪切强度、横向拉伸强度和纵向拉伸强度分别为74.64MPa、25.34MPa和2256MPa,比芳纶/EP复合材料的相应强度分别提高了28.7%、32.5%和13.4%,其复合材料破坏面的形貌也说明芳纶纤维与AFR树脂之间的界面粘结性能较好。     

Wetting and adhesion behavior of armos fibers after dielectric barrier discharge plasma treatment

To investigate the influence of atmospheric plasma treatment on aramid fiber wetting and adhesion behavior, an air dielectric barrier discharge (DBD) was applied to the Armos aramid fiber surface at different discharge power densities. Dynamic contact angle analysis indicated that the total surface free energy was increased from 49.6 to 68.3 mJ/m 2 , an increment of 37.7%, whereas the single-fiber tensile strength testing showed that the mechanical properties of the Armos fibers were almost unaffected. With the enhancement of fiber surface wettability, the interlaminar shear strength, which was used to determine the interfacial adhesion in Armos-fiber-reinforced thermoplastic poly(phthalazinone ether sulfone ketone) composites, increased by 17.2% to 71.4 MPa. Scanning electron microscopy photos showed that the predominant failure mode of the composites changed from interface failure to matrix and/or fiber failure after the plasma treatment. Taken together, these results suggest that the air DBD plasma was an effective technique for improving the surface and interfacial performance of the Armos fibers without damaging their bulk properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The Tribological Properties of Polypropylene Composite Filled with DBD-Treated Carbon Fiber

Dielectric barrier discharges (DBD) in ambient air are used on carbon fiber to improve the carbon fiber surface activity. Carbon fibers with length of 75 um are placed into the plasma configuration. The tribological properties of polypropylene filled with untreated and DBD treated carbon fiber are comparatively investigated. Results show that DBD treatment greatly improve the friction and wear properties of carbon fiber reinforced polypropylene composite (CF/PP).     

Highly Hydrophobic Wood Surfaces Prepared by Treatment With Atmospheric Pressure Dielectric Barrier Discharges

Atmospheric dielectric barrier discharge (DBD) treatments of wood were done to attain water repellency on wood surfaces. A specially designed frequency controlled parallel-plate DBD reactor was utilized to produce the discharges. Ethylene, methane, chlorotrifluoroethylene and hexafluoropropylene were used as DBD reagents. Contact angle, water absorption, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements on the modified surfaces were performed. For methane and ethylene, XPS data showed an increased surface atomic concentration of carbon from 72.7% on untreated samples up to 80.7 and 96%, respectively, whereas nearly 50% fluorine concentration was observed with fluorinated reagents. The C_1s spectrum of hexafluoropropylene-DBD-treated wood sample showed that the CF₃ group was introduced in a relative amount of 19%. AFM images showed distinct features for each of the DBD treatments, such as a deposit of a thin uniform film in the case of ethylene-DBD treatment, whereas the hexafluoropropylene-DBD treatment resulted in the nucleation of plasma-derived entities at the fiber surface and the subsequent growth of a film. Under optimized conditions the water contact angle was in the range of 139°–145°. The combination of depositing a low surface energy polymer on an already rough surface gave the surface-treated wood a highly hydrophobic character.     

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。     

The TPB Properties of Plasma-Treated Carbon Fiber-Reinforced Polystyrene Composites

Dielectric barrier discharges (DBD) in ambient air are used on carbon fiber to improve the fiber surface activity. Carbon fibers with length of 75 µm are placed into the plasma configuration. The interaction between modified carbon fibers and polystyrene was studied by the three-point bending (TPB) test. The chemical and physical changes induced by the treatments on carbon fiber surface are examined using contact angle measurements and X-ray photoelectron spectroscopy (XPS). Contact angles of the plasma-treated carbon fiber and XPS results reveal that the carbon fibers modified with the DBD at an atmospheric pressure show a significant increase in oxygen and nitrogen concentration. These results demonstrate that the surfaces of the carbon fiber are more active, hydrophilic after plasma treatments using a DBD operating in ambient air.     

Influence of plasma treatment on properties of ramie fiber and the reinforced composites

In this research, 9 series of ramie fibers were treated under low-temperature plasma with diverse output powers and treatment times. By analysis of the surface energy and adhesion power with epoxy resin, 3 groups as well as control group were chosen as reinforced fibers of composites. The influences of these parameters on the ramie fiber and its composites such as topography and mechanical properties were tested by scanning electron microscopy (SEM), atomic force microscopy (AFM), tensile property and fragmentation test of single-fiber composites. Contact angle and surface free energy results indicated that with the increased treatment times and output powers, surface energy and adhesion work with epoxy resin improved. Compared with the untreated fibers, surface energy and adhesion work with epoxy resin grew 124.5 and 59.1% after 3 min-200 w treatment. SEM and AFM showed low temperature plasma treatment etched the surface of ramie fiber to enhance the coherence between fiber and resin, consequently fiber was not easy to pull-out. After 3 min-200 w treatment, tensile strength of ramie fiber was 253.8 MPa, it had about 30.5% more than that of untreated fiber reinforced composite. Interface shear stress was complicated which was affected by properties of fiber, resin and interface. Fragmentation test showed biggest interface shear stress achieved 17.2 MPa, which represented a 54.0% increase over untreated fiber reinforced composites.     

Wettability assessment of plasma-treated PBO fibers based on thermogravimetric analysis

Changes in the surface wettability of poly(p-phenylene benzobisoxazole) (PBO) fibers were investigated by thermogravimetric analysis (TGA) following an air dielectric barrier discharge (DBD) plasma treatment. The results were then supplemented and confirmed by scanning electron microscopy (SEM), dynamic contact angle analysis (DCAA), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements. After exposure to the DBD plasma at a pre-determined power level, TGA analysis showed that the residual rates retained by the PBO composites decreased, which meant an increase in the amount of resin coating the PBO fibers in the composites. Observations by SEM confirmed that there was more resin adhering to the treated PBO fibers and the wetting behavior of resin on the fibers was greatly improved. Meanwhile, DCAA for the treated fibers showed a significant enhancement in fiber surface free energy. XPS and AFM were performed in order to reveal any variations in fiber surface activity and surface morphology resulting from the surface treatment. The resulting data showed that increases in oxygen-containing polar groups and surface roughness on the plasma-treated PBO fibers contributed to the above improved wetting behavior. With comprehensive analyses, it was concluded that TGA could be used as a supporting method assessing the surface wettability of PBO fibers before and after air DBD plasma treatment.     

Long Term Effects of Air Dielectric Barrier Discharge Treatment on the Surface Properties of Ethylene Vinyl Acetate (EVA)

This paper discusses the long term effects of dielectric barrier discharge (DBD) treatment on the surface properties of ethylene vinyl acetate (EVA) film. The EVA surface was characterised using contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and 180° peel tests. EVA subjected to two different treatment times was compared to as-received and solvent cleaned film. The long term stability of the surface modification induced by the DBD treatment was studied over a period of 466 days. On initial application of DBD treatment to the EVA surface an increased wettability was observed, evident from a decreased water contact angle, improved peel strength when bonded, and an increased level of carbon–oxygen moieties measured using XPS. However, over the storage period of 466 days the material reverted to almost its original state with the contact angle being only ～3° lower than that of as-received EVA compared to a difference ～25° directly after treatment. AFM measurements showed that the treatment had a slight smoothing effect on the surface topography.