Thermal degradation behavior of polyamide 6/clay nanocomposites
Thermal degradation behavior of polyamide 6/clay nanocomposites
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DOI：
10.1016/s0141-3910(03)00061-2
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发表时间：
2003-07-01
影响因子：
5.9
通讯作者：
Sue, HJ
中科院分区：
文献类型：
--
作者：
Pramoda, KP;Liu, TX;Sue, HJ
本文主要研究了热重分析（TGA）与傅里叶变换红外（FTIR）光谱联用技术在热降解和逸出气体分析中的应用，热重-红外光谱（TG-IR）研究了熔融共混法制备的尼龙6（PA 6）和PA 6-粘土纳米复合材料。PA 6及其粘土纳米复合材料的热分解首先发生环状单体（己内酰胺）的释放，然后是其他挥发性气体如CO2和NH3，其特征在于在红外（IR）光谱中存在具有腈和乙烯基链端的低聚产物。对于具有2.5wt.%的PA 6，降解的起始温度高12 ℃。而对于具有较高粘土负载量（即5、7.5和10 wt.%）的样品，降解的起始温度几乎保持不变粘土）。上述发现与形态学观察有关，所述形态学观察显示仅对于具有2.5重量%的纳米复合材料具有最佳剥离结构。粘土，和明显的粘土团聚在那些具有较高的粘土负载。我们的研究表明，只有剥离的聚合物/粘土纳米复合材料表现出改善的热稳定性。附聚的粘土颗粒不显著影响聚合物基质的热稳定性。通过Kissinger方法估计的PA 6和PA 6 -2.5 wt.%的降解活化能E-a，发现粘土纳米复合材料在N-2中分别为175和199 kJ/mol，在空气中分别为228和223 kJ/mol。(C)2003爱思唯尔科技有限公司。保留所有权利。
This paper focuses on the study of thermal degradation and evolved gas analysis using thermogravimetric analysis (TGA) coupled to Fourier transform infrared (FTIR) spectroscopy, i.e., TG-IR, to study polyamide 6 (PA6) and PA6-clay nanocomposites prepared by melt compounding. The thermal decomposition of PA6 and its clay nanocomposites takes place with the evolution of the cyclic monomer (caprolactam) first, followed by other volatile gases like CO2 and NH3, which are characterized by the presence of oligomeric products with nitrile and vinyl chain ends in the infrared (IR) spectra. The onset temperature for degradation is 12 degreesC higher for PA6 with 2.5 wt.% of clay loading than that for neat PA6, whereas, the onset temperature for degradation remained almost unchanged for samples with higher clay loading (i.e. 5, 7.5 and 10 wt.% clay). The above findings are related to the morphological observations that show an optimal exfoliated structure only for the nanocomposite with 2.5 wt.% clay, and distinct clay agglomeration in those with higher clay loadings. Our study suggests that only exfoliated polymer/clay nanocomposites exhibit improved thermal stability. Agglomerated clay particles do not significantly affect thermal stability of the polymer matrix. The activation energies for degradation, E-a, estimated by Kissinger method, for PA6 and PA6-2.5 wt.% clay nanocomposite were found to be 175 and 199 kJ/mol in N-2, and 228 and 223 kJ/mol in air, respectively. (C) 2003 Elsevier Science Ltd. All rights reserved.