螺桿攪拌條件對製品形態學之影響

Abstract

以往製備含油自潤軸承試樣時使用通常之射出機, 由於塑料和油質二相混 合時形成混合不勻, 使螺桿無法利用摩擦料, 這種現象當提高溫度欲熔塑 料時更為顯著, 用雙螺桿擠出機時, 因塑料可以先熔後, 在某一定位加入 油質,可完全解決固液相分離問題. 從複合材料觀點看是愈混合均勻愈為 理想但是含油自潤材則有不同的要求條件, 也就是油相須以連續分散於塑 料基質, 而非孤立分散,否則油質被隔離不能滲透到表面發揮潤滑功能所 以研究油進料位置, 螺桿組合之變化;溫度;擠出速度等變化, 探討對擠出 物形態學之影響. 其檢驗除用SEM 目視之外, 更以磨潤效果等來予以驗 證, 乃是本研究之目研究結果顯示第二進料以後之混捏段予以取消, 使油 質分散相孔粒較大提高油質分散成連續相趨勢, 而降低變成孤立且細粒化 情形. 溫度對形態學之影響比螺桿組態的影響稍為小, 但以低溫較有利於 油質相粗粒化及連續化. 螺桿轉速之影響不甚大. 製品含油量完全受螺桿 組和溫度影響一致, 即油相粗粒化和愈有連續化者其含油量較大. 磨擦係 數和含油量呈反比例, 在荷重約 6.4kgf/cm2 時有小波峰產生, 於 30 kgf/cm2 附近有一較大波峰出現, 然後隨著荷重提高而磨擦係數可降低 達0.03左右. 至於滑速對磨擦係數影響不大, 拉伸強度也受到形態學影 響, 油質分散較粗大者其強度較大. This project aims to study the effect of screw kneading condition on the morphology of product made by a segmented twin screw extruder when the feeds of polymer pellets and oil contained reinforcements operate at different sits. Results show that to remove the kneading section located after the 2nd input section, selecting lower barrel temperature and lower rotation of screw could improve the state of oil phase in matrix. That increase the tendency of forming a larger particle and contineously. Which makes lower value of frictional coefficient. The amount of oil containing also agrees as well as the morphology effected by the conditions of kneading and barrel temperature. The frictional coefficient proportion to the amount of oil content inversely, which decreases with the increase of loading and to reach a low value of about 0.03.