共查询到7条相似文献,搜索用时 15 毫秒
1.
《Journal of Adhesion Science and Technology》2013,27(8):663-676
One of the main differences between low-pressure and atmospheric-pressure plasma treatments is that there is little moisture involved in the low-pressure plasma treatment, although moisture could exist at the wall of the vacuum chamber or react with the substrate after plasma treatment, while in the atmospheric-pressure plasma treatment moisture exists not only in the environment but also in any hygroscopic substrate. In order to investigate the influence of environmental moisture on the effect of atmospheric pressure plasma treatment, ultra-high-modulus polyethylene (UHMPE) fibers were treated using an atmospheric-pressure plasma jet (APPJ) with 10 l/min helium gas-flow rate, treatment nozzle temperature of 100°C and 5 W output power. The plasma treatments were carried out at three different relative humidity levels, namely 5, 59 and 100%. After the plasma treatments, the surface roughness increased while the water-contact angle decreased with increasing relative humidity. The number of oxygen containing groups increased as the environmental moisture content increased. The interfacial shear strength of the UHMPE fiber/epoxy system was significantly increased after the plasma treatments, but the moisture level in the APPJ environment did not have a significant influence on the adhesion properties. In addition, no significant difference in single fiber tensile strength was observed after the plasma treatments at all moisture levels. Therefore, it was concluded that the environmental moisture did not significantly influence the effect of atmospheric-pressure plasma treatment in improving interfacial bonding between the fiber and epoxy. The improvement of the interfacial shear strength for the plasma-treated samples at all moisture levels was mainly due to the increased surface roughness and increased surface oxygen and nitrogen contents due to the plasma etching and surface modification effect. 相似文献
2.
《Journal of Adhesion Science and Technology》2013,27(6):847-860
In order to investigate the effect of atmospheric pressure plasmas on adhesion between aramid fibers and epoxy, aramid fibers were treated with atmospheric pressure helium/air for 15, 30 and 60 s on a capacitively-coupled device at a frequency of 5.0 kHz and He outlet pressure of 3.43 kPa. SEM analysis at 10 000× magnification showed no significant surface morphological change resulted from the plasma treatments. XPS analysis showed a decrease in carbon content and an increase in oxygen content. Deconvolution analysis of C1s, N1s and O1s peaks showed an increase in surface hydroxyl groups that can interact with epoxy resin. The microbond test showed that the plasma treatment for 60 s increased interfacial shear strength by 109% over that of the control (untreated). The atmospheric pressure plasma increased single fiber tensile strength by 16-26%. 相似文献
3.
《Journal of Adhesion Science and Technology》2013,27(1):99-107
Ultrahigh-modulus polyethylene fibers were treated with atmospheric pressure He plasma on a capacitively coupled device at a frequency of 7.5 kHz and a He partial vapor pressure of 3.43 × 103 Pa. The fibers were treated for 0, 1, and 2 min. Microscopic analysis showed that the surfaces of the fibers treated with He plasma were etched and that the 2-min He plasma-treated group had rougher surfaces than the 1-min He plasma-treated group. XPS analysis showed a 200% increase in the oxygen content and a 200% increase in the concentration of C—O bonds (from 11.4% to 31%) and the appearance of C=O bonds (from 0% to 7.6%) on the surface of plasma-treated fibers for the 2-min He plasma-treated group. In the microbond test, the 2-min He plasma-treated group had a 100% increase of interfacial shear strength over that of the control group, while the 1-min He plasma-treated group did not show a significant difference from the control group. The 2-min He plasma-treated group also showed a 14% higher single-fiber tensile strength than the control group. 相似文献
4.
《Journal of Adhesion Science and Technology》2013,27(14):1407-1424
A nanoparticle dispersion is known to enhance the mechanical properties of a variety of polymers and resins. In this work, the effects of silica (SiO2) nanoparticle loading (0–2 wt%) and ammonia/ethylene plasma-treated fibers on the interfacial and mechanical properties of carbon fiber–epoxy composites were characterized. Single fiber composite (SFC) tests were performed to determine the fiber/resin interfacial shear strength (IFSS). Tensile tests on pure epoxy resin specimens were also performed to quantify mechanical property changes with silica content. The results indicated that up to 2% SiO2 nanoparticle loading had only a little effect on the mechanical properties. For untreated fibers, the IFSS was comparable for all epoxy resins. With ethylene/ammonia plasma treated fibers, specimens exhibited a substantial increase in IFSS by 2 to 3 times, independent of SiO2 loading. The highest IFSS value obtained was 146 MPa for plasma-treated fibers. Interaction between the fiber sizing and plasma treatment may be a critical factor in this IFSS increase. The results suggest that the fiber/epoxy interface is not affected by the incorporation of up to 2% SiO2 nanoparticles. Furthermore, the fiber surface modification through plasma treatment is an effective method to improve and control adhesion between fiber and resin. 相似文献
5.
《Journal of Adhesion Science and Technology》2013,27(8):1071-1083
The effects of aging temperature and time on the adhesion properties of oxygen plasmatreated low-density polyethylene (LDPE) were investigated. As the aging temperature and time increased, surface rearrangement and the migration of molecules containing polar functional groups into the bulk were accelerated to the surface to form a hydrophobic surface. The adhesion strength of oxygen plasma-treated LDPE/aluminum joints was measured using a 90° peel test by varying the plasma treatment time and aging temperature. The adhesion strength was constant, regardless of the plasma treatment time. As the aging temperature increased, the adhesion strength of the LDPE/aluminum joints decreased and the locus of failure changed from cohesive to interfacial failure. It was also found that the polar functional groups buried in the bulk could be reoriented to the surface in a polar environment. This study also investigated whether repeated oxygen plasma treatment would increase the concentration of polar functional groups at the surface and reduce the surface rearrangement and the migration of molecules containing polar functional groups during aging. Contact angle measurements and X-ray photoelectron spectroscopy (XPS) showed that repeated oxygen plasma treatments increased the concentration of polar functional groups at the surface. However, the aging time between plasma treatments had a negligible effect on the concentration of polar functional groups at the surface. 相似文献
6.
《Journal of Adhesion Science and Technology》2013,27(5):387-409
Vectran® fibers, made using liquid crystalline polyester, were treated with pulsed XeCl excimer laser (308 nm) to alter their surface characteristics and, thus, improve their adhesion to epoxy resin. The treatments were carried out in air using varying numbers of pulses at different laser fluences. The effects of laser treatment on the fiber surface topography, chemistry and wettability have been investigated. Fiber/epoxy resin interfacial shear strength was measured using the microbead test. The surface roughness was characterized qualitatively and quantitatively using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Changes in the surface energy were characterized using the Wilhelmy technique. Based on the SEM micrographs, the threshold fluence for the formation of surface structure was found to be less than 36 mJ/(pulse ? cm2). The laser treatments at fluences higher than the threshold fluence introduced periodic roll (wavy) structures on the fiber surface transverse to the fiber axis. From the AFM results, the fiber surface roughness was found to increase by up to 3.5 times the control fiber after the laser treatment. The dispersion component of the surface energy decreased, while the acid–base component of the surface energy increased significantly from 0 to 8.8 mJ/m2 after the laser treatment. The Vectran® fiber/epoxy resin IFSS increased by up to 75% after the laser treatment. This improvement is mainly attributed to higher surface roughness of the fiber. 相似文献