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標題: | 以奈米壓痕試驗及雷射掃描式共軛焦顯微技術評估高分子系統的耐刮性 Scratch Resistance Assessments of Polymeric Systems – Using Instrumented Indentation Testing and Laser Scanning Confocal Microscopy |
作者: | Yu-Hsin Huang 黃宇欣 |
指導教授: | 馬劍清(Chien-Ching Ma) |
關鍵字: | 奈米壓痕試驗,雷射共軛焦顯微技術,奈米碳,玻璃轉移溫度,彈性模數,硬度,耐刮性, Instrumented indentation technique,Laser scanning confocal microscopy,Nanoparticle silica,Glass transition temperature,Elastic modulus,Hardness,Scratch resistance, |
出版年 : | 2010 |
學位: | 碩士 |
摘要: | 本論文結合了奈米壓痕試驗 (instrumented indentation technique) 及雷射共軛焦顯微技術 (laser scanning confocal microscopy) 來評估高分子系統的耐刮性 (scratch resistance),並且研究不同玻璃轉移溫度與奈米添加物極性,對於高分子聚合物表面機械性質的影響。利用連續剛性量測技術 (continuous stiffness measurement method),奈米材料的彈性模數與硬度可以由奈米壓痕試驗所測定。耐刮性研究主要是基於測量刮痕的損傷變形,佐以分析刮痕測試得到的深度、寬度、彈性回復指數、摩擦係數等資訊來定性評估材料的耐久性 (durability)。刮痕測試的施行,包括了連續增加負載與定量負載兩種方式。連續增加負載的刮痕測試提供了傷痕由無到有生成的完整資訊,並且可用來粗估代表了材料彈性至塑性變形的臨界破壞力 (onset force);一系列定量負載的刮痕測試,則可用來精確評估材料的臨界破壞力,並藉此作為材料間傷痕肇始 (彈性至塑性變形) 相對於耐刮性比較的依據。本文中所有的刮痕形態,包括了刮痕深度、寬度和邊緣堆積高度,皆是使用雷射共軛焦顯微技術量測和分析,並且進一步用作耐刮性的評估。
實驗材料包括了兩個高分子系統: 1. 交聯結構的環氧樹脂 (epoxy) ,具有不同的玻璃轉移溫度 2. 聚胺甲酸酯 (polyurethane) 薄膜,添加了2% 不同極性的奈米矽顆粒。在第一個研究個案中,玻璃轉移溫度對於刮痕測試的影響非常顯著,高的玻璃轉移溫度對應於高的耐刮性。第二個研究個案中,兩組含有奈米矽的聚胺甲酸酯薄膜按照不同的製備方式製成。第一組的材料較薄而且有著較高的玻璃轉移溫度 (~ 90 ℃),第二組材料較厚而且有著較低的玻璃轉移溫度 (~ 55 ℃)。第一組的實驗試片 (control sample) 與對照組試片 (reference group)有著非常近似的機械性質與刮痕形態,因此耐刮性的評估並不顯著。另一方面,第二組的實驗試片對於傷痕的抵抗力較弱,刮痕測試後得到的初始損傷深度是最嚴重的。然而,經過了16個小時,其復原的行為卻比其他對照組試片都快,傷痕變得寬而淺,可見度也降低了。依照整體來觀察,玻璃轉移溫度較低的聚胺甲酸酯組別,在刮痕試驗裡表現出了較嚴重的損傷變形。因此,由兩個高分子系統的研究中共同顯示,增加材料的玻璃轉移溫度可以使得抗刮性提升。 In this thesis, a combination of instrumented indentation technique (IIT) and laser scanning confocal microscopy (LSCM) was used to assess the scratch resistance of polymer systems. The effect of glass transition temperatures Tg and nanoparticle additive polarities on the surface mechanical properties and scratch resistance of polymers were investigated. By the continuous stiffness measurement (CSM) method, the elastic modulus and hardness of polymer systems were measured using IIT. The scratch resistance assessment was based on measuring the damage deformation and analyzing the scratch data, such as the scratch depths, scratch width, recovery, and friction coefficient as a qualitative method to evaluate the durability of the polymer system. Two types of scratch test methods were used: the progressive force and constant force scratch tests. The onset force at which scratch damage changed from elastic (total recover, invisible) to plastic (visible) deformation was approximately estimated from the progressive force scratch test. From an array of constant force scratch test, the onset force was determined more accurately. The onset force of elastic-plastic deformation can be used as an indicator to rank scratch resistance of a polymer system. The scratch morphology including scratch depths, scratch width, pile-up height were measured using LSCM. The scratch morphological data were analyzed and also used to assess the scratch resistance of the system. Two polymer systems were studied in this thesis: 1. Crosslinked epoxy (EP) systems with different glass transition temperatures; 2. Polyurethane (PU) thin films containing 2 % nanosilica (SiO2) with dispersant/additive of different polarities. In the first case study, the effect of glass transition temperature on the scratch behavior was evident. The higher glass transition temperature, the higher scratch resistance. In the second case study, two series of the PU-SiO2 films were used due to different preparation conditions. Series 1 is thinner and has a higher glass transition temperature (~ 90 oC), and series 2 is thicker and has a lower glass transition temperature (~ 55 oC). In series 1, the control sample and reference group had similar mechanical data and scratch morphology so that the final ranking of scratch resistance is not clear. On the other hand, the control sample in the series 2 has the weakest scratch resistance and worst damage right after scratched. However, after 16 hours, the scratch damage of control sample (in series 2) recovered faster than that of the reference group. The scratch morphology of control sample (in series 2) became wider and shallower and less visible. Overall, the scratch damages were found to be more severe in the series with the lower glass transition temperature. Therefore, the testing results in both case studies indicated that the higher glass transition temperature had a stronger scratch resistance. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/8655 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 機械工程學系 |
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