The Research On The Properties And Polymer-Polymer Miscibility Of PA6/PTFE Alloys

Owing to the particularity of working condition and the complexity of the serious corrosion environment and friction problems in oil wells, it is necessary to select a protective coating material for the flexible continuous sucking rod. Currently it is general to choose the PA6 as the coating material. However PA6 has its proper deficiency, such as absorption of water, instability in dimensions and so on. In order to improve the overall properties, we concentrated our efforts on the surface and bulk modification of the matrix materials PA6. A large number of experimentation research are made through blending or copolymerization to modify the materials properties (such as: resistance to corrosion, friction and abrasion; self-lubricity; high performance in low temperance, resistance to absorption of water, stability in dimensions, and so on.). So we can select the optimum synthetic process and the most suitable formula. In order to evaluate the quality of miscibility of the two different polymers, we also use the Scanning Electron Microscope to analyze the microstructure and the polymer-polymer miscibility of polymer alloys.First, in order for the coating material to possess excellent chemical-resistance and self-lubricity, we choose the PTFE as the improver of the quality. PTFE has been of interests as broad temperature range, chemical-resistance as well as resistance to friction and abrasion. But PA6 is a strong polar macromolecule, while PTFE is the polymer without polarity. Meanwhile their miscibility index difference is larger than 7, that is to say, A 6 > 7. It is very difficult to blend PA6 and PTFE mechanically. Here the key problem is to figure out proper synthesis methods and technology to resolve the polymer-polymer miscibility. Then three synthesis techniques and formulae have been determined to achieve the polymer alloys:One is to directly blend the PA6 and PTFE mechanically to produce the PA6/PTFE (80/20) alloy. Second is to polymerize PA6 and PTFE simultaneously in the same polymerizing tank to produce the PA6/PTFE (80/20) SIN system. Third is to incorporate of a third component, two different reactive organo-silicone oligomers into the PA6 and PTFE respectively and then combine PA6 and PTFE. The reaction and cross-linking of the two reactive silicone resin interlock the PA6 and PTFE macromolecules so as to produce the PA6/ Silicone/PTFE (84/3/13) IPN system.In order for us to evaluate their polymer-polymer miscibility, we measured their densities and took the microstructure photos. Through analyzing the obtained data, we draw the conclusion that the PA6/PTFE (80/20) SIN system and PA6/ Silicone Resin/PTFE (84/3/13) IPN system have improved compatibility as well as enhanced chemical-resistance, resistance to water, resistance to wear and tear, and so on.Second, through contrastive experiments, the properties of three different polymer alloys have been tested and compared, such as: resistance to corrosion; resistance to friction and abrasion; self-lubricity; high performance in low and high temperance, ability to resist water, stability in dimensions, and so on. After carefully comparing the properties of three different polymer alloys, the third synthesis technology and formula PA6/Organo-silicone Resin/PTFE (84/3/13) was finally conformed for its lower cost, convenience to produce, very excellent quality, and so on.Finally, the direction of research to change the capability of polyamide coating materials is also furthered.