Modification Of Polymer Surface By Water-Mixed Plasma Jet And Its Related Applications

Polymer has many excellent mechanical properties(high temperature resistance and good corrosion resistance,etc.),and is widely used in industrial and medical fields.However,the practical application of polyethylene are sometimes limited because of the van der Waals force between the connected molecules result to its poor wettability,poor adhesion resistance and poor processing performance.Therefore,surface modification of polymer needs to be performed before its usage to solve the problem of polymer and further expand the application of the polymer.Currently,plasma is a common method for modifying polymers,but it is also limited by problems such as low active particle concentration and low modification efficiency.Mixed-vapor plasma jet(MR-APPJ)is a new modification technology which improve the concentration of active particles in the jet by mixing water vapor to achieve rapid long-term modification for polymer surface modification.Basing on the analysis of various polymer modification methods,the paper starts from the mechanism of MR-APPJ generation and research on the generation of MR-APPJ.Using the MR-APPJ modify the polymer surface and study the effect of MR-APPJ on the wettability and mechanical properties of the polymer surface,and utilize its mechanism to further expanding polymer surface application.The main research work of this thesis can be summarized as follows:In order to create the MR-APPJ which suitable for polymer modification,a home-made discharge device is used to investigate the effect of the mixing ratio on the discharge voltage and current and the stability of the jet length.It is finally determined that under the atmospheric pressure environment,use nitrogen as the main working gas,and the discharge mode is discharged by the bare metal electrode,the discharge voltage U = 1.64 kV,the water mixing ratio is between 0% and 2.5%,It is possible to produce the MR-APPJ which is uniformly stable in discharge and has a macroscopic length suitable for polymer modification.In order to study the effect and mechanism of the MR-APPJ on polymer surface modification,using MR-APPJ hydrophilic modification of PE,PEEK and PTFE and the modification of PE mechanical properties.The test results show that the MR-APPJ can quickly change the wettability and improve mechanical properties of the polymer especially when modifying with a high water-mixing ratio,the long-term wettability of the surface can be ensured by micro-etching of the surface.Basing on the mechanism of MR-APPJ modification,the paper will further expand the application of MR-APPJ to polymer surface modification.In order to study the effect of the MR-APPJ on the surface modification of polymer,the first part will study the effect of the MR-APPJ modification on the blood affinity of PEEK.The experimental results show that the MR-APPJ can significantly improve the surface blood affinity of PEEK,when use of MR2%-APPJ can significantly prolong the timeliness of blood affinity;afterwards,the study uses the MR-APPJ perform an auxiliary micro-milling test on the polymer under different cut depths.The test results show that the MR-APPJ can effectively reduce the cutting force during the machining process and effectively improve the quality of each machined surface.