本研究中利用原位聚合法來製備聚甲基丙烯酸甲酯/蒙脫土的奈米複合材料。由於黏土層間含有許多極性基團,所以我們先將助觸媒架附到黏土層間保護這些官能基,避免觸媒被毒化,讓隨後加入的Metallocene catalyst中心金屬帶正電而具有活性,確保單體能夠由黏土層間開始成長,藉由鏈成長的爆發力使黏土均勻分散在高分子中,最後希望形成剝離態,以達到奈米級的複合材料(Exfoliated nanocomposites)。實驗按五種不同觸媒,分別以蒙脫土含量、反應溫度、助觸媒濃度、預活化時間…等為變因做一系列的探討。利用1H NMR與FTIR做結構鑑定、以13C NMR判定PMMA的立體特異性;並以穿透式電子顯微鏡(TEM)觀看黏土的分散程度;再利用X光粉末繞射分析儀(XRD)計算Clay層間的距離;並以凝膠滲透層析儀(GPC)量測高分子之分子量與分子量分佈;而熱性質的測定則是以微差掃描卡計 (DSC)和熱重分析儀(TGA)測得;最後再利用掃描式電子顯微鏡分析儀(SEM)觀察PMMA/Clay的抗刮性。
In this study, poly(methyl methacrylate)(PMMA) / clay are prepared by in situ polymerization. We use the metallocene / MAO catalyst to prepare the PMMA/clay via coordinated polymerization to make silicate layer dispersing in the polymer. There are many polar groups in the silicate layer so we have to use the co-catalyst, MAO, support on the interlayer of clay to protect the functional groups and to avoid the catalyst be poisoned. Polymerization is processed with the catalyst, which is on the interlayer of clay, to be sure that polymeric chains grow between the layers of clay.Five catalysts were used in this study,discuss the condition of clay catain,reaction temp.,concentration of cocatalysts and the aging time.Molecular weight and Molecular weight distribution were measured by gel-permeation chromatography(GPC). The structure of the covalent bonds was Identified by Fourier-transform infared (FT-IR).The clay dispersion was measured by both X-ray diffraction And the thermal stability of nanocomposites were studied by differential scanning calorimetry(DSC) and thermogravimetric analysis (TGA).SEM micrograph of fractured surface of PMMA nanocomposites.