Effect of Alkyl Side Chain Length on Relaxation Behaviors in Poly(n-alkyl Acrylates) and Poly(n-alkyl Methacrylates) |
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| Authors: | Xiaojun He Jinrong Wu Guangsu Huang Xiaoan Wang |
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| Affiliation: | College of Polymer Science and Engineering , State Key Laboratory of Polymer Material Engineering, Sichuan University , Chengdu, China |
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| Abstract: | Dynamic mechanical analysis (DMA) is used to investigate the effect of alkyl side chain length on the relaxation behavior of poly(n-alkyl acrylates) (PnAA) and poly(n-alkyl methacrylates) (PnAMA) above the glass transition temperature (Tg). Master curves and shift factors (log aT) were obtained using the time–temperature superposition (TTS) principle. The log aT curves of PnAA and PnAMA exhibit a dynamic crossover from one Vogel–Fulcher–Tammann–Hesse (VFTH) equation to another above Tg. The corresponding temperature was designated as the dynamic crossover temperature (Tc). It is found that Tc/Tg and the apparent activation energy (Eg) increases, e whereas the fragility index (m) decreases with increasing alkyl side chain length. Further analysis shows that m ∝ Tg, Eg∝  | |
| Keywords: | dynamic crossover temperature dynamic mechanical analysis fragility index poly(n-alkyl acrylates) poly(n-alkyl methacrylates) relaxation behavior |
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