アイソタクチックポリプロピレン溶融物の低ずり速度領域におけるずり流動特性と定常流動停止後の応力緩和

• 上出 健二

  旭化成工業株式会社繊維研究所

• 渡部 武

  旭化成工業株式会社繊維研究所

書誌事項

タイトル別名

• Flow Characteristics of Isotactic Polypropylene Melt in the Region of Low Shear Rate and Its Stress Relaxation Following after Sudden Cessation of Flow

抄録

Flow behaviors of isotactic polypropylene melt and it's stress relaxation following after sudden cessation of flow have been studied. Viscosity measurements were performed at 250°C at shear rates ranging from 2.72×10^-2 to 2.08×10 sec^-1 under nitrogen atmosphere by using a cone-and-plate rotating viscometer. Six fractions and a whole polymer having viscosity-average molecular weights M_v ranging from 6.2×10⁴ to 39.6×10⁴ were used. The sample in powder form were molded before use into disks, 4 cm in diameter and 0.04cm thick. It was observed for samples having larger M_v under larger shear rate that shear stress passed through a maximum which was followed by a pronounced decrease to it's steady value. The time necessary for attaining steady state was strongly influenced by both M_v and shear rate. It became clear that in capillary flow of melt the contribution of transient unsteady flow accompanied by the disentanglement of entangled networks to melt viscosity obtained can not be ignorable. The shear rate at which the transition from Newtonian to non-Newtonian flow occurred was inversely proportional to M_v<BR>The slope of double logarithmic plots of zero shear viscosity against M_v, was found to be 3.6, approximately agreeing with the value expected from the theory. Stress relaxation at constant deformation after the rotation had been stopped was found to be non-linear even if the steady flow preceding sudden cessation was Newtonian, leading to conclusions that the phenomenological cause for non-linear stress relaxation is non-Hookian properties of elastic elements in a melt, and that the method for evaluating the recoverable shear strain from the data of end correction factor in capillary flow of the melt is, in principle, inapplicable.

収録刊行物

• 高分子化學

  高分子化學 26 (291), 498-510, 1969

  公益社団法人 高分子学会

詳細情報

• CRID: 1390001206520137984
• NII論文ID: 130004032810
• DOI: 10.1295/koron1944.26.498
• ISSN: 18848079
• ISSN: 00232556
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可