| Abstract: | 關鍵詞:高填充高分子;塑性流體;靜態及動態降服應力;搖變性;流變測試 本研究以各種流變測試,如定剪應力,定剪速率及動態測試等,以量測高填 充熱塑性高分子複材流體之降服應力.而降服應力之量測將隨時間而異,即 判斷流體是否開始持續流動,或已完全靜止,均與觀察時間長短有關.諸如 此類在實驗中遭遇的困難,及實驗方法的操作與方法,將有深入的分析.同 時觀察時間之選擇,將與實際應用程序的特徵時間相配合. 研究 裡將檢測的流變性質包括:穩態流變測試之黏度與剪速率,剪應力的關係; 第一正向應力差與剪速率之關係;不同頻率及震幅下之線性與非線性黏彈 性質;變化剪速率時,搖變及暫態流變實驗之應力響應;靜態及動態降服應 力. 在穩態,動態及暫態等流變實驗 測試中,可以直接量測複材流體的彈性上限降服應力,動態降服應力及靜態 降服應力外,並且可以知道,填充物濃度越高將使複材流體中的降服應力越 大;填充物顆粒越小,將使複材流體的降服應力越大;填充物粒徑表面經過 鈦系偶合劑塗佈後,會使流體所具有的降服值降低等,填充物對高分子流體 流變性質的影響.以及相關直接量測降服應力的方法,與流變測試的限制與 範圍.
Keywords:highly filled polymmer melt;static and dynamic yield stress;thixotrop y;rheologic measurement Yield stress of highly filled thermoplastics shall be probed using various techniques such asconstant shear stress "constant shear rate" and oscillatory shear .the magnitude of the result is expectedto depend on the time allowed to determine whether the sample has developed continuous flow or has ceased flowing .The difficulties encountered in the experiments shall be critically discussed .It has been well known that the choiceof observation time or shear rate in the measurement should be related to the characteristic time of the flow process to which the result is to be applied . The rheological properties examined:(1)steady shear viscosity as a function of shear rate ,(2)first normal stress differenceof shear rate ,(3)linear/nonlinear viscoelastic properties as function of frequency and amplitude ,(4)thixotropic and transient shear stress response to changes in shear rates and rest time ,(5)static and dynamic yield stress. |
