奈米高分子複材微細發泡射出成型

Study on the Properties of Microcellular Injection Molded Polymer Nanocomposites Parts

10.6623/chem.2012001

黃世欣(Shyh-Shin Hwang)；李政謙(Cheng-Chen Lee)

蒙脫土 ； 微細發泡 ； 奈米複材 ； 插層型 ； 熔融混鍊 ； 原位聚合 ； Organoclay ； Nanocomposites ； Microcellular ； In-situ polymerization ； Melt compounding

化學

70卷1期（2012 / 03 / 01）

1 - 12

繁體中文

本研究在探討一般高分子和奈米高分子複材之微細發泡(Microcellular) 射出成型之差異性，微細發泡是利用超臨界流體將氮氣增壓至超臨界狀態再打入射出機和熔融塑膠混合成單相溶液並維持在高壓系統，在射出那一瞬間，系統產生熱力學不穩定現象，而使超臨界流體開始成核，進而開始發泡。塑膠發泡一般用於減震，絕熱之應用，塑膠如果加入一些填充物，如：玻纖，可以增加成核點使氣泡數量增加而氣泡變小。近幾年來，奈米材料相當盛行，故也有把奈米材料的黏土(Clay)加入塑膠材料中，奈米高分子複材應用於塑膠發泡可得到比塑膠添加玻纖有更小的氣泡大小，本計畫探討尼龍6材料，添加不同蒙脫土(MMT)含量，製備方式分別用原位(in situ)聚合和雙螺桿混鍊2種，並用不同螺桿轉速看其對機械、熱性質、發泡性質之影響。螺桿轉速會影響剪切力(Shear force)，進而影響奈米材料在塑膠材料之分散性，分散性好不好對材料提升機械性質幫助很大，奈米材料加進塑膠材料內可增加發泡之成核點進而增加氣泡數量且減少氣泡尺寸，分散性也會影響發泡性質。

Polyamide 6 (PA6)/MMT nanocomposites prepared by in-situ polymerization and melt compounding methods were used in this study. The organoclay PA6 nanocomposites were then injection molded by conventional and microcellular methods. Carbon dioxide was used as the blowing agent. The effect of injection screw speed, organoclay content, and preparation methods on the mechanical/thermal properties was investigated. The results showed that the screw speed of the injection had major effect on the mechanical properties of the nanocomposites: the higher the screw speed, the greater the tensile strength. The nanocomposites have maximum tensile strength, wear resistance, and cell density at a clay loading of 3 wt% and 5 wt% for in-situ polymerization and melt compounding respectively. The addition of MMT also improved the thermal stability of the PA 6/clay nanocomposites. The XRD results showed that the nanocomposites had no diffraction peaks when made by melt compounding.