| 研究実績の概要 |
1,3:2,4-Bis(3,4‐dimethylbenzylidene)sorbitol, DMDBS, is efficient in enhancing the drawdown force, defined as a force required for stretching a molten strand. Under shear and extension flow using a capillary rheometer, the nanofibrils that preferentially orient to the flow direction induce rapid crystallization of PP during uniaxial elongational flow. This behavior is responsible for the pronounced enhancement of the drawdown force in PP containing DMDBS. The force arising from the network structure of DMDBS fibers may contribute the high level of the drawdown force. Because a high level of drawdown force is required for various PP processing operations, this technique will be immediately applicable to the plastics industry.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
We aim to implement our technology for industrial troubleshooting. In the present research, we found that the addition of a small amount of DMDBS is the effective way for enhancing transparency and show good nucleating ability, significantly enhancing the crystallization temperature. Nanofibers of DMDBS, which show significant alignment in the flow direction, are responsible for the rapid crystallization of PP in the flow field leading to an increase of drawdown force. Because we realize the importance of this result providing fundamental information useful in polymer processing, the industrial knowledge regarding the relationship between nucleating ability and rheological response has been revealed through paper publication in Journal of Applied Polymer of Science in 2018 that all goes according to expected plan.
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| 今後の研究の推進方策 |
Based on our concept, the drawdown force of the PP molecular chains is enhanced by addition of the nucleating agent owing to the rapid crystallization of PP in the flow field. This characteristic provides easier processability and better bubble stability at polymer processing. Therefore, applying this knowledge to various materials exhibiting strain hardening during film elongation such as broad molecular weight distribution and long-chain branch polymers is aimed. Moreover, PP containing various types of nucleating agent that enhances the orientation in the flow direction will be considered. The study in crystallization dynamics in the flow field and orientation relaxation of molecular chains is expected to discover the new principle.
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