Online ISSN : 1883-7417
Print ISSN : 0915-4027
ISSN-L : 0915-4027
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Seikei-Kakou Autumnal Meeting 2023
Special Issue on Seikei-Kakou Autumnal Meeting 2023
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Technical Note —Keynote Lecture in Seikei-Kakou Autumnal Meeting 2023
Technical Reports
Report from Universities and Institutions in Japan : 233
Original Papers
  • Takumi Yamada, Momoko Kasatani, Masayuki Kobayashi, Kosuke Ootsuka, Ta ...
    2024 Volume 36 Issue 5 Pages 210-215
    Published: April 20, 2024
    Released on J-STAGE: May 20, 2024

    Polyamide MXD6 is used as a packaging material for films and PET bottles because of its excellent gas barrier properties. One of the requirements for MXD6 is the suppression of gelation during film manufacturing because it leads to defective appearance and unstable production. To elucidate the gelation mechanism, heat deterioration behavior of retained MXD6 in an extruder was investigated. This paper reports the investigation results and shows the presumed gelation mechanism of MXD6 and anti-gelation mechanism based on the addition of sodium acetate and PA6. Furthermore, evaluation results of anti-gelation formula by a new evaluation method were reported. As a result of various investigations, it was estimated that MXD6 gelation proceeds in four steps. At first, MXD6 undergoes hydrolysis during heat retention to form amino and carboxy terminals. After that, generated carboxy terminal is eliminated as a cyclopentanone causing rapid increase of amino terminal. Then the reaction between these amino terminals forms secondary amines. Finally, they react with the carboxyl end group to generate tertiary amides presumed to be a cause of MXD6 gel. Addition of sodium acetate and PA6 to MXD6 suppresses the gelation. Our investigation results suggested that this is probably due to the suppression of tertiary amides generation through the action of sodium acetate and PA6 as a base or through cyclization of the PA6. To demonstrate effectiveness of anti-gelation formula, new gelation test method using an extruder was devised. In contrast to the conventional simplified method (heat-press), this method accurately reproduces the retention in an extruder. As a result, addition of sodium acetate and PA6 performed a gelation inhibit effect even in this test. From this results, anti-gelation formula is expected to be useful in film manufacturing. Also, both tests show almost the same results, indicating that both test methods are useful for evaluating gelation behavior.

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  • Ken Sudo, Yohei Koori, Minoru Senga, Kenta Ito, Hideyuki Uematsu, Masa ...
    2024 Volume 36 Issue 5 Pages 216-223
    Published: April 20, 2024
    Released on J-STAGE: May 20, 2024

    We have previously reported that blending syndiotactic polystyrene (SPS) with acid-modified polyphenylene ether (c-PPE), which is compatible with the amorphous chains of SPS, improves the interfacial shear strength between CF. We have also shown that c-PPE, which has higher interfacial shear strength between CF than SPS, is self-localized on the CF surface. However, this selflocalization has been observed under static conditions (static holding in the molten state) in the microdroplet method, but the influence of blending (melt kneading), a dynamic condition, on the interfacial strength has not been clarified. In this report, we investigated the effect of c-PPE addition on the mechanical properties of injection-molded SPS/CF composites by preparing samples at different kneading temperatures in a twin-screw kneader, which is widely used in industry due to its high productivity. The mechanical properties of SPS/CF were improved by the addition of c-PPE, and the effect of adding c-PPE on the mechanical properties of SPS/CF was enhanced at higher kneading temperatures. Higher kneading temperatures promoted the self-localization of c-PPE on the CF surface and increased the chemical interaction at the c-PPE-CF surface.

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