Study and Development of 3D Printed Piezoresistive Polymer Composites

隨著3D列印技術的發展，其應用的領域也越來越廣泛。本研究以發展光固化型的壓阻材料做為3D列印應用為目標，將導電碳材料碳黑加入於光固化樹脂中，透過超音波均質的方式將碳黑均勻的分散在光固化樹脂當中，並透過調整碳黑與光固化樹脂兩者的比例，來使得調製出的光固化複合高分子樹脂不僅具有導電性並且也有壓阻特性，而成為壓阻複合高分子，之後使用光固化型式的數位光處理 (Digital Light Processing, DLP) 3D列印技術來進行印製出壓阻感測材料。實驗部分，本研究比較使用兩種溶劑N-甲基吡咯烷酮(N-methyl-2-pyrrolidone, NMP )及異丙醇(isopropanol, IPA)於導電光固化樹脂製作中的分散碳黑的效果及製作出來的試片其電性及壓阻特性。而評估其壓阻特性方式為架設一拉伸試驗機構來進行實驗，之後計算出不同碳黑濃度的壓阻複合高分子的壓阻應變係數來評估其材料的壓阻特性。 實驗結果，以NMP及IPA分別為分散碳黑用溶劑的導電光固化樹脂的導電的關鍵濃度分別為1.0-1.5 wt%之間及0.5-1.0 wt%之間。壓阻感測極限應變量，以IPA製作出來的壓阻複合高分子感測極限應變量最多可達7%而NMP的為4%；而壓阻應變係數(Gauge factor)的計算結果，最佳結果以IPA為分散溶劑製作的碳黑濃度為1.0 wt%的壓阻複合高分子為5.2，而隨著濃度增加，壓阻複合高分子的壓阻應變係數會愈低，代表材料之感測敏感度愈不佳。DLP 3D列印之結果目前可以初步的固化成型。本研究希望未來此研究可以應用於感測器原件開發及製作上面作為使用。達到減化製程步驟、縮短製作時間並且降低成本的一種新穎感測元件製作方式。With the 3D printing technique development, there are more and more different applications and research fields employed 3D printing technique. The purpose of this study is to develop a piezoresistive composite polymer material that can be applied on photocurable Digital light processing (DLP) 3D printing to fabricate. The conductive particles material, carbon black (CB), was added into the photocuarble resin to make the conductive photocuable resin. The different amount of the conductive CB was employed for obtaining the conductive percolation threshold and the piezoresistivity of the polymer composites. In order to disperse the CB uniformly, the carbon black dispersion was dispersed in two kinds of solvents, N-methyl-2-pyrrolidone (NMP) and isopropanol (IPA), by the ultrasonic homogenizer. Then the CB dispersion was mixed with photocuarble resin to obtain the conductive photocuable resin. The CB dispersing situation, the conductivity and piezoresistivity of conductive photocuable resin were measured and discussed in this work. A tensile measurement equipment was set up for measuring the piezoresistivity of the fabricated piezoresistive sample. The conductive percolation threshold of the composite polymer was 1.0-1.5 wt% and 0.5-1.0 wt% for the polymer composites fabricated by NMP and IPA solvents, respectively. The maximum sensing limit strain was obtained 7% and 4% for the polymer composites fabricated with IPA and NMP, respectively. The highest gauge factor result was the 1.0 wt% concentration polymer composites fabricated with IPA is 5.2. As the concentration increases, the gauge factor of the piezoresistive polymer composites will be lower, indicating the sensing sensitivity of the material is poor. The fabrication results of DLP 3D printing for the fabricated photocuable resin can be cured and formed any designed patterns. This study can be applied to the development and production of sensor in the future for achieving the reduction process step, shortening production time, and cut cost those benefits.摘要 i Abstract ii 目錄 iv 表目錄 vi 圖目錄 vii 第1章 緒論 1 1.1 前言及研究動機 1 1.2 文獻回顧 2 1.3 研究目標和論文架構 10 第2章 實驗原理及設計 13 2.1 壓阻高分子 13 2.1.1 導電高分子 13 2.1.2 壓阻複合材料 13 2.1.3 導電關鍵濃度 16 2.2 導電材料與分散 18 2.2.1 碳黑 18 2.2.2 固體粒子分散 19 2.3 光固化3D列印 20 2.3.1 光固化樹脂 20 2.3.2 光固化 3D列印 22 第3章 製作方法及實驗 26 3.1 壓阻材料製作 26 3.1.1 導電光固化樹脂製作 26 3.1.2 壓阻材料試片製作 32 3.2 拉伸實驗的架設 34 3.3 數位光處理DLP 3D列印步驟 36 第4章 結果與討論 38 4.1 碳黑分散情形 38 4.2 導電性量測 42 4.2.1 電阻值與薄膜厚度量測 42 4.2.2 電阻率/導電度計算 45 4.3 壓阻拉伸實驗結果 48 4.3.1 壓阻材料之感測極限應變 48 4.3.2 壓阻應變係數 55 4.3.3 壓阻材料感測重複性 58 4.4 數位光處理DLP 3D列印成果 60 第5章 結論與未來展望 61 參考文獻 6