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Tham khảo tài liệu 'conductive polymers and plastics in industrial applications part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 36 Conductive Polymers and Plastics EXPERIMENTAL SAMPLE PREPARATION Neat s-PS resin with an average molecular weight of400 000 was kindly donated by the Dow Chemical Company. The raw material was dried in a vacuum oven at 85oC for 12 hours before molding. sPS disks with a diameter of 20 mm and thickness of 0.8 mm were made by a Carver compression molding machine. Mold temperature was set at 280oC. To ensure smooth surfaces of the samples two glass plates and a template made of copper were used to mold the samples. IMPLANT PROCEDURE Ion implantation experiments were performed at the Acadiana Research Laboratory with a National Electrostatics Corporation 5SDH-2 1.7 MV Tandem Pelletron Accelerator. The accelerator system has two ion sources the Source of Negative Ions by Cesium Sputtering SNICS to produce heavy ions and the Radio Frequency RF sources to produce helium ions. Carbon ions were produced from a graphite pellet inside the SNICS source of the accelerator. The pressure in the system was maintained at 10-7Torr. A PPT Residual Gas Analyzer RGA was attached to the chamber to monitor the gas emission from the sPS samples during the implantation. In the first part of this research the carbon ions were kept at a constant energy of 1.0 MeV but the dose was varied from 1011 ions cm2 to 1015 ions cm2. In the second part of this research the implanted dose was kept to be 1013 ions cm2 but the energy changed from 0.5 MeV to 4.0 MeV. Low current densities around 25 nA cm2 were used in both cases to minimize the effects of beam heating. CHARACTERIZATION OF SURFACE STRUCTURE AND PROPERTIES Surface composition was analyzed by a Residual Gas Analyzer RGA and a Elastic Recoil Detection Analysis ERD . Surface morphology and roughness were measured by Atomic Force Microscopy AFM . Surface hardness was studied by a Nanoindenter. Wear resistance and friction coefficient were investigated by a Tribometer. Surface wettability and contact angles were characterized by a Kruess .
