The completely alternating copolymerization of propylene sulfide with carbon disulfide was first achieved. Copolymerization by using anionic initiator [Ph3PNPPh3]Cl gave poly(propylene trithiocarbonate). The addition of chromium complex was found to accelerate the copolymerization. The obtained copolymer has a completely alternating structure with high regioregularity and showed large refractive index of 1.781∼1.782.

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Poly-Ether-Ether-Ketone (PEEK) has been widely used for tribological applications with steel counterparts because of its superior mechanical and self-lubricating properties. Fluid lubrication has the potential to further improve the performance of PEEK/steel contacts but its effect has been shown to depend on the operating conditions. To elucidate these aspects and establish the mechanism of fluid lubrication, the friction and wear properties of the PEEK/steel contacts in both dry and poly-α-olefin (PAO) lubricated conditions were investigated by tribological tests and surface analytical techniques. The nanoindentation measurements showed that lubrication with PAO had a softening effect on the wear track of PEEK, but no correlation was established with the wear of PEEK. The tribological behavior, for both dry and lubricated contacts, was correlated with the thickness of PEEK transfer films on the steel counterparts. The thickness of these films, as determined by Electron Probe Micro Analysis (EPMA) and X-ray Photoelectron Spectroscopy (XPS), was controlled by the rates of their formation and removal and depended on the operating conditions. Moreover, lubrication with PAO inhibited not only the formation but also the removal of PEEK transfer films. This study thus sheds light on the mechanism of fluid lubrication of the PEEK/steel contacts.

This study proposes a novel approach for controlling frictional performances at paper clutch systems by a combination of organic friction modifiers (OFMs). The OFMs are commonly used for modifying the frictional properties at the paper clutch. Although the effect of the OFMs tends to be dependent on temperature due to their working mechanism based on the surface adsorption, the frictional properties are preferable to be stable in all the operating temperature for the consistent and precise clutch control. Aiming to modify the temperature dependence of the OFM effect, an OFM with an Advanced Concept (FMAC) was newly developed, and the impact on the clutch frictional performance was investigated using Low Velocity Friction Apparatus (LVFA). Only with the conventional OFM, the friction values experienced excessive reduction at 80 or 120°C, while an optimal property was achieved at 40°C. In the presence of the FMAC, it was possible to inhibit the conventional OFM selectively at the high temperature conditions preventing the friction reduction, leading to the ideal frictional property in all the temperature conditions. The surface analysis revealed that the FMACs were capable of adsorbing on the substrate more intensively at high temperature, which should be the reason of the temperature dependent competitive effect of the FMACs.