Degradation induced variation of LC transition of poly(n-undecyl isocyanate)
- 作者：Bi-Zen Hsieh ; Hung-Yi Chuang ; Liang Chao ; Ying-Jie Huang ; Po-Hao Tseng ; Tar-Hwa Hsieh ; Yu-Kai Han ; Ko-Shan Ho
- 关键词：Liquid crystal transition ; Poly(n-undecyl isocyanate) ; Degradation ; Trimer
- 刊名：Polymer Degradation and Stability
- 出版年：2008
- 期刊代码：85_01413910
- 类别：ms
- 出版时间：May 2008
- 卷：93
- 期：5
- 页码：983-989
- 文件大小：986 K
摘要
The first-order thermal transitions including side-chain melting, crystal-LC, biphasic chimney-like, and isotropic transitions of poly(n-undecyl isocyanate) (PUDIC) were investigated by varying its thermal history. After annealing at 140 °C for different periods of time, it leads to different degrees of backbiting degradation into n-undecyl isocyanurate trimer which behaves as a solvent for the rest non-degraded/rigid PUDIC to change into a lyotropic LC from thermotropic transition. Based on the degree of degradation, various amounts of trimers are present and the PUDIC demonstrates different types of thermal transitions found in DSC thermograms due to the variation of the non-degraded PUDIC concentration in solvent trimers. Finally, a phase diagram includes all types of crystallines, LC, and isotropic regions can be drawn according to the DSC thermograms.