Characteristic of polymer viscous flow 1.链段的蠕动实现整个分子的迁移 2.不符合牛顿流体的流动规律 Bingham ≠n-=7y Pseudoplastic Ky Dilatant Newtonian Dilatant Newtonian Pseudoplastic Shear rate
Characteristic of polymer viscous flow 1. 䬮⇥Ⲵ㹅ࣘᇎ⧠ᮤњ࠶ᆀⲴ䗱〫 d dt J V K KJ z n V J K V J Bingham Pseudoplastic Dilatant Newtonian 2. нㅖਸ⢋亯⍱փⲴ⍱ࣘ㿴ᖻ 26
Shear thinning (剪切变稀) Newtonian fluid △388 423 T(K) ▲443 513 10 is-1)
Shear thinning (࠷࢚ਈ〰) 27
3.流动时伴有高弹形变 Time-dependent shear stress and primary normal stress difference after start-up of steady shearing 10 b T=150°C 2 2 Time, t[sec]
Time-dependent shear stress and primary normal stress difference after start-up of steady shearing 28 3. ⍱ࣘᰦդᴹ儈ᕩᖒਈ
Relaxation of shear stress and primary normal stress difterence after cessation of steady-state shearing 2 Time, t [s]
Relaxation of shear stress and primary normal stress difference after cessation of steady-state shearing 29
3.流动时伴有高弹形变 Consider a steady simple shear flow Shear force a八ywoA S Shear force >Die- swell(出口胀大) Extrudate swell →s observed for a melt of Die-gwell PS for various shear rates and temperatures. Burke. J. J: etc Characterization of 200° Materials in Research Syracuse UnIv Press, 1975.) shear rate at wall [s1
3. ⍱ࣘᰦդᴹ儈ᕩᖒਈ ¾ Consider a steady simple shear flow Shear force Without Shear force ¾ Die-swell (ࠪਓ㛰བྷ) Extrudate swell observed for a melt of PS for various shear rates and temperatures. (Burke, J. J.; etc. Characterization of Materials in Research, Syracuse Univ. Press, 1975.) 30