Preparation and Physical Properties of Epoxy/Modified Montmorillonite Nanocomposites

本研究先將蒙脫土製備成有機改質帶有環氧基官能基後，再添加入環氧樹脂(DGEBA)中並與硬化劑進行開環加成反應製備成環氧樹脂/改質蒙脫土之奈米複合材料，所使用硬化劑為聚醚胺(D230)。先將蒙脫土吸附改質矽烷 (Modified silane, MS)後，再添加四乙氧基矽烷(Tetra-ethyl orthosilicate, TEOS)，使得在蒙脫土表面上生成二氧化矽，形成蒙脫土/二氧化矽奈米混成材料 (MMT/SiO2 Nanohybrids, C1S1)，之後再與 3-(三甲氧基矽)-1-丙醇甲基丙烯酸 ﹝3-(Trimethoxy silyl)-1-propanolmethacrylate, MPS﹞反應，使蒙脫土上二氧化矽原子表面上帶有 C=C 雙鍵，形成蒙脫土/二氧化矽奈米混成材料接枝 MPS (C1S1-M)。之後再進一步將甲基丙烯酸環氧丙酯 (Glycidyl methacrylate, GMA)及苯乙烯 (Styrene)以吸附微胞聚合法 (Admicellar polymerization)聚合於蒙脫土表面上已接枝的 MPS 上，形成蒙脫土/二氧化矽奈米混成材料接枝 MPS 後微胞聚合 GMA/Styrene (C1S1-M-GS)。而甲基丙烯酸環氧丙酯具有環氧基，可與帶環氧基的環氧樹脂產生相容性，此作用可進一步幫助環氧樹脂進入黏土層間。 在添加甲基丙烯酸環氧丙酯/苯乙烯重量比 1:3 後，所進行吸附微胞聚合後所得到之改質蒙脫土 (C1S1-M-GS)，由 FTIR 分析得知，可發現 Si-O-Si 拉伸振動峰與甲基丙烯酸環氧丙酯及苯乙烯特徵峰，由XRD 分析得知，C1S1-M-GS 為脫層結構。可知此有機改質蒙脫土符合製備環氧樹脂與改質蒙脫土複材用途。 製備環氧樹脂/改質蒙脫土奈米複合材料，由 XRD 分析得知，複材中添加改質蒙脫土後皆為脫層結構。並由 SEM 破壞表面紋路分析發現，其添加改質蒙脫土後表面結構佈滿條紋且隨著改質蒙脫土含量增加其條紋密集度亦更加明顯。由 DMA 分析在添加 1 wt %改質蒙脫土後，環氧樹脂/改質蒙脫土複材之玻璃轉移溫度從 86.3 ℃下降至 80.5℃，而添加 2、3 wt %改質蒙脫土之複材其玻璃轉移溫度更下降至 71.5℃、71.1 ℃，可知隨著改質蒙脫土重量百分比越高，其玻璃轉移溫度越低，顯示改質蒙脫土會阻礙環氧樹脂高分子鏈段的交聯反應，造成 交聯密度不足。而環氧樹脂/改質蒙脫土複材，其儲存模數從基材的 2.73E8 Pa 提升至添加 1 wt %、2 wt %、3 wt %改質蒙脫土之複材的 2.88 E8Pa、2.95 E8 Pa、2.99 E8 Pa，分別提升 5.47 %、8.13 %、9.72 %，因此隨著改質蒙脫土重量百分比越高，其儲存模數越高，顯示改質蒙脫土的確可提升剛性。另一方面，添加改質蒙脫土之複材其透氧量從基材的 2.97 cc/m2-day 下降至添加 3 wt %、6 wt %、9 wt %改質蒙脫土之複材的 2.42 cc/m2-day、0.76 cc/m2-day、0.42 cc/m2-day，而且隨著改質蒙脫土重量百分比越高，透氧量越低，顯示改質蒙脫土在環氧樹脂中能有效阻隔氧氣的通過。並且在進一步分析透氧量後，可由 Nielsen 公式微分後代入得到最符合透氧曲線之長徑比為 350。In this study, we first prepared the modified montmorillonite (MMT) having epoxy functional groups and added it into the epoxy to form nanocomposites. The curing agent is polyetheramine, D230, that used for the preparation of nanocomposites by ring-opening reaction of the epoxy functional groups in epoxy resin. The modified MMT was done by treating MMT with a modified silane (MS), and Then tetraethylorthosilicate (TEOS) was added to form nanosilica particles on the MMT surface. Then, the reaction of 3-(Trimethoxy silyl)-1-propanol methacrylate (MPS) on MMT/SiO2 nanohybrids (C1S1) was done to bring the C=C function groups. Finally, glycidyl methacrylate (GMA) and styrene were polymerized on the outer surface of MMT/SiO2 nanohybrids by admicellar polymerization. Because the glycidyl methacrylate itself contains epoxy functional group, it can enhance the dispersion of modified MMT dispersed in epoxy resin. Hence, it can be expected to improve the compatibility and uniform dispersion in the epoxy resin. For admicellar polymerization, glycidyl methacrylate and styrene monomers at weight ratio of 1:3 were added to obtain poly (glycidyl methacrylate-co-styrene) grafted on a MMT/SiO2 nanohybrids grafted with MPS. The characteristic spectrometric peaks of glycidylmethacrylate and styrene were studied by FTIR. The Si-O vibrational stretching form MMT/SiO2 nanohybrids is revealed. We found that MMT/SiO2 nanohybrids exhibit no diffraction peaks between 1.5 to 8 degree by XRD, suggesting the distance of interlayer of modified clay above 5.88 nm (1.5°). Subsequently, the epoxy/modified MMT nanocomposites were prepared and further analyzed. By XRD analysis, it was shown that the exfoliation of modified MMT at 1~3 wt % loading was achieved. By inspecting the SEM fracture photographs, we found that the surface structure was covered with stripes for epoxy/modified MMT nanocomposites. When the modified MMT in the nanocomposites reaches 3.0 wt %, the number of stripes were increased significantly. In the DMA analysis, the glass transition temperature was measured. While adding 1、2、3 wt % modified MMT in nanocomposites, the glass transition temperatures were dropped to 80.5 ℃、71.5 ℃、71.1 ℃ compared with 86.3 ℃ for pure epoxy resin after curing. The decrease of glass transition temperature is explained by the confinement of polymer chains embedded in the MMT gallery and limits their segmental motions and results in insufficient crosslinking density. Also, the storage modulus was studied. The E’ value increased form 2.73 E8 Pa for pure epoxy, to 2.88、2.95、2.99 E8 Pa for 1、2、3 wt % modified MMT in nanocomposites at 30 ℃. The increased percentage of E’ value was found to be 5.47、8.13、9.72 % for 1、2、3 wt % loading of modified MMT.This means the modified MMT can effectively enhance the storge modulus. From the oxygen transmission rate analysis, the oxygen permeability decreased form 2.97 cc/m2-day matrix substrate to 2.42、0.76、0.42 cc/m2-day of 3、6、9 wt % of modified MMT of nanocomposites. We can see the oxygen barrier properties of polymers can be significantly increased by inclusion of clay platelets due to the increase of diffusion path for gas molecules. Finally, the oxygen transmission rate further was analyzed and found the MMT platelets form this thesis shows the aspect ratio of 350 for MMT dispersed in epoxy nanocomposite.中文摘要 I 英文摘要 III 謝誌 V 目錄 VI 表目錄 VIII 圖目錄 IX Scheme目錄 XII 一、緒論 1 1.1前言 1 1.2環氧樹脂簡介 2 1.3奈米蒙脫土簡介 4 1.4高分子/蒙脫土奈米複合材料 5 1.5研究目的 6 1.6研究方法與實驗流程 6 二、文獻回顧 17 2.1蒙脫土(MMT)/二氧化矽混成材料相關文獻 17 2.2蒙脫土接枝高分子相關文獻 20 2.3環氧樹脂(Epoxy)與蒙脫土複合材料相關文獻 26 2.4奈米複材之阻氣性相關文獻 32 三、實驗 37 3.1實驗儀器 37 3.2實驗藥品 38 3.3實驗步驟 40 四、結果與討論 43 4.1改質矽烷(ModifiedSilane,MS)之製備與鑑定分析 43 4.1.1紅外線光譜之官能基分析 43 4.2蒙脫土/二氧化矽混成材料與接枝MPS後分析之製備與鑑定分析 44 4.2.1紅外線光譜之官能基分析 45 4.2.2熱重損之無機物固含量分析 47 4.2.3X-ray繞射儀之層間距離分析 48 4.2.4蒙脫土/二氧化矽混成材料之SEM分析 50 4.3蒙脫土/二氧化矽混成材料接枝MPS表面聚合甲基丙烯酸環氧丙酯/苯乙烯之製備與鑑定分析 52 4.3.1紅外線光譜之官能基分析 53 4.3.2熱重損失之無機物固含量分析 54 4.3.3X-ray繞射儀之層間距離分析 56 4.4環氧樹脂/改質蒙脫土複材物性分析 57 4.4.1一般物性與化性之分析 58 4.4.1.1紅外線光譜之官能基分析 58 4.4.1.2熱重損失之無機物固含量分析 60 4.4.1.3X-ray繞射儀之層間距離分析 62 4.4.1.4動態機械(DMA)性質之分析 63 4.4.2阻氣性之探討 67 4.4.2.1透氧量分析 67 4.4.3形態學分析探討 73 4.4.3.1場發射式電子顯微鏡之斷裂面型態分析 73 五、結論 83 六、參考文獻 8