As presented in Table 1, the char residue of PEPA modified PURFs increased with the content of PEPA. It should be highlighted that the char residue reached 32.5% at 800 °C when 8 wt% of PEPA was added, while the char residue of pure PURF was only 17.2%.
On the basis of TG and DTG results, the thermal decomposition of PURF with and without PEPA exhibited quite different behaviors. In order to confirm the above decomposition mechanisms, FTIR and XPS were used to analyze the structure and composition of the char formed at different temperatures.
In comparison with PURF, PEPA modified PURFs showed slight weight loss at 100–200 °C, and the weight loss increased with the PEPA content at 250–380 °C. It can be proposed that the weight loss here was caused by two reasons, one was the similar weight loss as pure PURF, and the other was caused by the decomposition of PURFs catalyzed by phosphorus acid that was generated by the degradation of PEPA. At 380–450 °C, the weight loss could be attributed to the dehydrogenation and dehydration of secondary polymers generated from soft segments. Finally, the weight loss became very slight at above 600 °C.
As presented in Table 1, the char residue of PEPA modified PURFs increased with the content of PEPA. It should be highlighted that the char residue reached 32.5% at 800 °C when 8 wt% of PEPA was added, while the char residue of pure PURF was only 17.2%.On the basis of TG and DTG results, the thermal decomposition of PURF with and without PEPA exhibited quite different behaviors. In order to confirm the above decomposition mechanisms, FTIR and XPS were used to analyze the structure and composition of the char formed at different temperatures.In comparison with PURF, PEPA modified PURFs showed slight weight loss at 100–200 °C, and the weight loss increased with the PEPA content at 250–380 °C. It can be proposed that the weight loss here was caused by two reasons, one was the similar weight loss as pure PURF, and the other was caused by the decomposition of PURFs catalyzed by phosphorus acid that was generated by the degradation of PEPA. At 380–450 °C, the weight loss could be attributed to the dehydrogenation and dehydration of secondary polymers generated from soft segments. Finally, the weight loss became very slight at above 600 °C.
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