複合材料由基材與補強材組成,普遍常被使用的基材多為高分子材料,具有彈性、輕巧等特質,奈米碳管具有極佳的力學特性與電、熱性質,因此極適合作為複合材料中的補強材料。本研究以多壁奈米碳管補強高分子樹脂,製備不同含量的多壁奈米碳管/環氧樹脂試片,並加入官能基化流程,探討基本機械特性-楊氏模數與抗拉強度隨添加碳管濃度的不同所產生的變化情形。此外亦探討此高分子複合材料的動態特性,動態特性包含阻尼比與自然頻率,本研究以有限單元分析模擬懸臂樑結構之模態及自然頻率,將模擬結果與振動實驗量測結果進行比較,討論參數的變化對模擬之自然頻率結果產生之影響,以及實驗中自然頻率隨著奈米碳管添加濃度不同而出現的變化情形。 實驗結果顯示添加多壁奈米碳管3.0 wt%,相較於純環氧樹脂其楊氏模數可提升11.3 %,而在添加2.0 wt%多壁奈米碳管時,抗拉強度可提升至19.7 %;共振頻率方面,實驗與模擬均顯示加入多壁碳管給予各模態之共振頻率提升效果有限,然而在結構抑震阻尼特性卻有不錯的效果,而透過改質可以大幅提升複合材料的拉伸韌性。最後以SEM觀察複合材料斷裂面之微結構,了解複合材料於拉伸負載下之破壞機制。
Composite is composed of matrix and reinforcement. Polymer materials are often as matrix, which has flexible, light and other advantages. CNTs having excellent mechanical, electrical and thermal properties, is very suitable to be used as the reinforcement in composites. In this study, MWNTs were uesd to reinforce polymer resin. Different weight percents of MWNTs/epoxy specimens were varied to explore the basic mechanical properties - Young's modulus and tensile strength. Besides the dynamic characteristics including natural frequency and damping ratio are also discussed. The finite element analysis was used to simulate modal and natural frequencies of specimens. This results were compared with the experimental measurements. The experimental results show that composites specimens with 2.0 wt% can improve 11.3% of its Young's modulus when compared to the pure epoxy. While adding 3.0 wt% MWNTs can improve the tensile strength to 19.7%. The results also show that adding MWNTs gives the natural frequency a little change at each mode, and a larger change in damping characteristics. In addition, a significant enhancement of the tensile toughness of the composites through functionalizion was found. Finally, SEM images of the fracture surface gives some explanation about the breaking mechanism in the microstructure.