The toughening of PA 66 blended with styrene-ethylene-butylene-styrene tri-block copolymer modified with maleic acid (M-SEBS) and the effect of addition of modified Polytetrafluoroetylene (PTFE) to PA 66/SEBS were examined. Toughness of PA 66 was improved remarkably by the blend of M-SEBS. The optimum amount of maleic acid was needed to improve the toughness of PA 66. Further amount did not contribute to the improvement of toughness. The addition of SEBS with low strength is effective to the nucleation of voids, and as a result, the toughness was effectively improved by the relaxation of stress concentration. The addition of modified PTFE to PA 66/SEBS blend was effective in further improving the toughness. It was presumed that the addition of modified PTFE results in the transformation of the spherulite of PA 66 and the formation of network structure of modified PTFE. As a result, the restraint of softening and the increase of orientation hardening were achieved.

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In this study, we examined to clarify main factor that affect to the liquid film surface appearance for multilayer flow that consisted of polymer solution of different rheological behavior. The correlation of the viscoelastic flow behavior in the three-layer channel and the liquid film surface appearance was examined by numerical analysis. As the results, the following technical findings were obtained. (1) The first normal stress difference generated in the sub-fluid, which was a main factor for the generation of the surface irregularity was large at the vena contracta and the merging part. However, the main factor for the generation of the surface irregularity was the first normal stress difference generated in the sub-fluid at the vena contracta. Because the first normal stress difference generated in the sub-fluid at the merging part was perfectly relaxed in the channel. (2) The factor analysis between layers was conducted to specify the main factor for the generation of the surface irregularity. As the result, it was understood that there is a strong correlation between the frequency of the surface irregularity and the force to act on the sub-fluid around the interface at the vena contracta (F_s). Moreover, it was understood that there is a correlation between F_s and the interfacial roughness (R_a-int) of the distance at the vena contracta to the discharge part. (3) Sharping the inflow angle and chamfering the inflow corner are effective to the reduction of the force both to act on the sub-fluid around the interface and to control the generation of the surface irregularity.

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To clarify the adhesion effects on the transcription of fine patterns to the surface of a thermoplastic polymer, the numerical simulation of the filling and transcription behavior in Melt Transcription Molding Process was carried out using a numerical model based on the adhesion between a molten polymer and a metal stamper with microstructure. The microstructure was completely transcribed at the initial stamper temperature 180℃. Up to this temperature, the rim height of transcribed hemispherical projection increased but the center height decreased, when the mold temperature was raised. The transcribed shapes simulated theoretically at the initial stamper temperature 170, 175 and 180℃ were closely duplicated with experimental ones which were reported in our previous study. Immediately after the release of compression force, the internal stress of the polymer filled near the contact interface changed from compression to tensile stress. From these results, it was confirmed that the adhesion force between the polymer filled in the microstructure and the metal mold surface keeps the transcribed shapes of the microstructure stable against the elastic recovery force. Furthermore, it was suggested that the adhesion effects play a critical role in successful operations of the coating, compression and demolding stages in Melt Transcription Molding Process.

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