2022 Fiscal Year Final Research Report

Study on the foaming process of microcellular plastics and its prediction by theoretical model

Research Project

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Project/Area Number	20H02506
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 27010:Transport phenomena and unit operations-related
Research Institution	Hiroshima University
Principal Investigator	Takishima Shigeki 広島大学, 先進理工系科学研究科(工), 教授 (10188120)
Co-Investigator(Kenkyū-buntansha)	木原伸一広島大学, 先進理工系科学研究科(工), 准教授 (30284524) 宇敷育男広島大学, 先進理工系科学研究科(工), 助教 (30734850)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	発泡プラスチック / 超臨界流体 / 気泡合一 / ガス溶解度 / 拡散係数 / 界面張力 / 物理発泡
Outline of Final Research Achievements	In addition to observing the bubble coalescence phenomena, a prediction model for the bubble coalescence rate that can quantitatively express the experimental result has been developed. The diameter and thickness of the contact surface between the bubbles could be expressed by combining a simple geometric model and a viscoelastic model. Furthermore, as a condition for rupture of the contact surface, it was revealed that the ratio of the diameter of the contact surface to the bubble diameter was about 0.4, thereby predicting the time until the rupture of the contact surface. Gas solubility, diffusion coefficient, viscosity, and interfacial tension required for foaming simulation have been measured for several systems and their prediction methods developed. Moreover, foaming experiments and simulations have been conducted for EVAc + CO2 system to clarify the effects of operating conditions, comonomer composition, and mixture properties on bubble formation and bubble growth.
Free Research Field	化学工学
Academic Significance and Societal Importance of the Research Achievements	発泡樹脂は日用品から構造部材まで幅広く大量に使用されている。本研究では物理発泡法で未解明であった気泡合一過程に対して気泡の接触から合一までの速度を表現する物理モデルを開発した。本モデルは気泡成長の初期段階におけるものであるが、これを応用することで後期段階の合一現象も近い将来に予測できると思われる。また、本研究では発泡シミュレーションに必要な各種物性値を蓄積すると共に、その推算法を進歩させた。以上の成果により、発泡過程全体のシミュレーションを用いた所望の発泡構造を得るための操作条件の予測に大きく前進し、軽量で高機能な製品の開発や化石原料の削減に貢献できると考えられる。