成形加工
Online ISSN : 1883-7417
Print ISSN : 0915-4027
ISSN-L : 0915-4027
34 巻, 3 号
選択された号の論文の13件中1~13を表示しています
目次
巻頭言
解説 : 特集 放射光利用技術の最前線
技術報告
プリンキピア ―常識を変えたモノたちの物語―
日本の大学・試験・研究機関の研究 : 224
会議・見本市だより
製品・技術紹介
論文
  • 渡邊 希, 髙澤 彩香, 山延 健, 上原 宏樹, 撹上 将規
    2022 年 34 巻 3 号 p. 103-110
    発行日: 2022/02/20
    公開日: 2022/03/20
    ジャーナル フリー

    Ultrahigh-molecular-weight polyethylene (UHMW-PE) can be drawn even from the molten state owing to its high melt viscosity. Molten UHMW-PE exhibits elastic deformability, which is homogeneously transmitted within the entire sample through molecular entanglements, resulting in oriented crystallization. Thus, entanglement characteristics are a dominant factor for the drawability of molten UHMW-PE. The entanglement characteristics of a UHMW-PE reactor powder will be retained for a film prepared by melt-processing due to the long relaxation time of UHMW-PE chains. Therefore, in this study, the melt-drawing behavior of UHMW-PE film prepared from different raw material powders was investigated. Three kinds of commercially available UHMW-PE reactor powders with comparable MW (viscosity average MW of 3×106) were used as a raw material. The UHMW-PE film was melt-drawn at 150℃, well above the sample melting temperature. The stress-strain curves recorded during melt-drawing exhibited a yield point, plateau stress region, and strain-hardening region for all films, although the stress level was different, indicating that the entangled state depends on the kind of raw material powder. In-situ wide-angle X-ray diffraction (WAXD) measurements during melt-drawing revealed two oriented crystallization mechanisms : the characteristic orthorhombic crystallization via transient hexagonal crystallization derived from deep entanglements, and the direct orthorhombic crystallization derived from shallow entanglements. Consequently, the entanglement characteristics of a UHMW-PE reactor powder dominate the melt-drawing behavior of the film. The obtained results are promising for developing the industrial melt-processing of UHMW-PE starting from a supplied UHMW-PE raw material powder.

ファウンテン・フロー
feedback
Top