Influence Of Glycerol Coating Pretreatment On Effectiveness Of Atmospheric Pressure Plasma Treatment Of Uhmpe

As far as textile fibers are concerned,plasma treatments are used as a means of surface modification on fibers to improve their wettability, shrink resistance,desizing and printability.Recently,with the increasing application of fiber-reinforced composites,more attention has been paid to take advantage of plasma treatments to solve the adhesion problems between the fiber and matrix caused by the smooth and inert surface of many reinforcing fibers.Due to the environment-friendliness and high efficiency,surface modifications by plasma treatments will have more and more extensive industrial applications in future.The atmospheric pressure plasma jet(APPJ) is a new kind of plasma source which can possibly takes the place of low-pressure plasma in some applications.Furthermore,one of the biggest differences between low pressure and atmospheric pressure plasma treatments is that there is no moisture involved in the low pressure plasma treatment while in the atmospheric pressure plasma treatments.In that case,moisture exists not only in the environment but also in any hygroscopic substrates.A potential problem for the atmospheric pressure plasma treatment (APPJ) is that the existent agents applied in the industry area absorbed by the substrate may influence the plasma surface modification processes.In order to investigate the etching effect of ultra high modulus polyethylene (UHMPE) fibers treated by helium APPJ,UHMPE fibers and different concentrations of glycerol solution were selected as a model fiber and the absorbed agents respectively.The results are correlated with the surface properties that are investigated by contact angle measurement,scanning electron micrograph(SEM),interfacial shear strength(IFSS) test and X-ray Photoelectron Spectroscopy(XPS),meanwhile,the fiber coating technique were combined with the helium plasma treatment.Under any treatment conditions,glycerol coating interlayer decreased the interfacial adhesion of UHMPE fiber/epoxy composites to different extents according to the concentrations of glycerol solution and SEM showed increased surface roughness,and the IFSS value had same decreased trend under dry and wet treatment condition.Contact angle analysis showed that immediately decreased angle formed after plasma treatment,while when the concentration raised,the recovery rate of contact angle increased.While XPS analysis revealed increased oxygen contents after the plasma treatments.In addition,longer treatment duration and higher output power were investigated in this study.