以DSC進行奈米碳管熱分析

Thermal Decomposition of Carbon Nanotube Powders by DSC

10.7005/JOSH.200809.0255

王順志(Shun-Chih Wang)；許維麟(Wei-Lin Syu)；陳勃翔(Po-Hsiang Chen)；張至維(Chih-Wei Chang)；徐啟銘(Chi-Min Shu)

奈米碳管 ； 微差掃描熱卡計 ； 分解熱 ； 起始設定溫度 ； 熱失控 ； Carbon nanotubes CNTs ； Differential scanning calorimetry DSC ； Exothermic onset temperature T0 ； Heat of decomposition △H(subscript d) ； Thermal runaway reaction

勞工安全衛生研究季刊

16卷3期（2008 / 09 / 01）

255 - 264

繁體中文

奈米碳管(carbon nanotubes, CNTs)是近年來出現的新穎材料，不過世人至今對於奈米碳管在熱危害特性上並未全然瞭解。因此本文將探討CNTs特有的熱穩定性，進而防止製程中可能會發生的熱危害，在有效時間內使用可靠的熱卡計來測得不同的熱動力學參數進行分析；本研究所使用的儀器為微差掃描熱卡計(differential scanning calorimetry, DSC)，實驗的物質有活性碳粉(powder activated carbon, PAC)、商用奈米碳管(commercial CNT, CBT)與創新複合材料多壁奈米碳管/氧化鋁(MWNT/Al2O3, CCNT)等；並於有效時間進行實驗，取得分解熱(heat of decomposition)數值並計算熱動力學參數。由於溫度的轉移呈不規則現象，故此起始設定溫度設定在30℃，在此時PAC、CBT與CCNT開始產生放熱溫度的波峰，實驗昇溫速率分別設定為2與4℃/min。在PAC、CBT與CCNT實驗結果進行比較，藉由CCNT的開始放熱反應的溫度與最低的分解熱並與PAC、CBT比較得知，CCNT為一較安全且低熱危害的物質。對PAC、CBT和CCNT等安定的碳進行試驗，在試驗期間得到不同的能量並以這些熱量作圖，瞭解其熱失控(thermal runaway)的現象，從中發現CCNT在加熱的放熱反應得基本程序中，隨著昇溫速率的提昇活化能也跟著增加。

Many concerns over unsafe or unknown properties of carbon nanotubes (CNTs) have been raised by many researchers. The thermal stability characteristics would represent potential hazards during the production or utilization stage and could be determined by calorimetry testing for various thermokinetic parameters. In this study, differential scanning calorimetry (DSC) was employed to analyze thermal decomposition and to calculate thermodynamic characters and dynamic parameters for activated carbon powder (C), commercial CNT (CBT), and an innovative composite of CNT on Al2O3 powders (CCNT) during the time-valid experiments. The temperature shifts were irregular in terms of onset temperatures about 30℃ for peak exothermal temperatures of C, CBT, and CCNT as heating rate augmented from 2 to 4℃/min. The higher heating temperature showed a thermal delay effect that increased the onset temperature and decreased the heat of decomposition for C, CBT and CCNT. By observation comparing results on C, CBT, and CCNT, CCNT has second starting temperature of exothermal reaction and lowest heat of decomposition and is a safer material (less thermal hazard) than C and CBT. In addition, the exothermal reaction is the first order for CCNT and has activation energy increase as the heating speed increases. In addition, our results implied that different types of carbon contained in C, CBT, and CCNT could yield different energies during heat composition.

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