Polymer00059 - exhibited a significantly larger weight loss...

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48 Both temperatures are used to compare the thermal stability of each formulation (Table 2). Figure 2.7a compares TGA weight loss curves of the neat FC 2260 and its nanocomposites comprising 2% nanofillers. It shows that the thermal stability of FC 2260 nanocomposites decreased with the addition of FS-clay and S-clay. This was especially true for S-clay, which lowered the T 5% from 452.3 o C for the neat FC 2260 to 425.7 o C for the nanocomposite containing 2% S-clay (Table 2). The addition of 4% of FS-clay or S- clay led to further decrease in the degradation temperature (Figure 2.7b and Table 2.2). Xie et al. (2001) indicated that the alkylammonium cations in the organoclay could decompose at elevated temperatures (150-300 o C ) , and the decomposition products would catalyze the degradation of polymer matrixes, which led to earlier degradation of the materials. Moreover, the nanofillers of FS-clay and S-clay themselves were more prone to thermal degradation than the other three nanofillers. As shown in Figure 2.8, they
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Unformatted text preview: exhibited a significantly larger weight loss than the other nanofillers at low temperatures (i.e. below the elastomer degradation temperature). These two factors together resulted in decreased T 5% for the nanocomposites comprising FS-clay and S-clay. However, the influences of silica and graphite on the degradation temperature of the elastomer was opposite from that of the nanoclays. FC 2260/T-G, FC 2260/UT-SiO 2 and FC 2260/T-SiO 2 all exhibited different degrees of improvement in thermal stability compared with the neat FC 2260. The effect of treated graphite on improving thermal stability seemed very limited. The addition of 2% T-G only slightly increased T 5% of the elastomer (~ 2 C increase), and 4% T-G only resulted an increase of ~ 6 C in T 5% . In contrast, silica nanoparticles, particularly the treated silica, greatly improved the thermal stability of the elastomer. While the addition of the untreated silica at 2 and 4 % loading...
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This note was uploaded on 08/18/2011 for the course MATSE 447 taught by Professor Colby,r during the Spring '08 term at Pennsylvania State University, University Park.

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