Aggregation and Gelation of Aromatic Polyamides with Parallel and Anti-parallel Dipoles along the Linear Backbone
The exploring of self-organizing mechanism of polymers is important to develop new structure and devices in industries.The aromatic polyamide furnishes sophisticated self-organization with kinds of interactions such as hydrophilic or hydrophobic effect, hydrogen bonding, and Coulombic interactions.We have synthesized two polyamides with parallel or anti-parallel dipoles along the linear backbone, named as ABAB and AABB respectively.The dipolar moment is about 3 Debye (Gaussian 03, DFT B3LYP, 6-311G**) for each polymer.The molecular weights are about 4000-6000 g/mol obtained from the analytical ultracentrifugate.It has been observed that the polymers in toluene (3 w/v％ for ABAB and 1 w/v％ for AABB) demonstrate a gelation point at room temperature and a clouding point at higher temperatures.By using the static and dynamic light scattering technique, the size and morphology change of ABAB and AABB with temperatures has been detected.From the dielectric relaxation spectroscopy there are two relaxations for both polymers, in which the slow mode is temperature dependent and follows the Arrhenius equation.The active energy of the slow-mode relaxation of ABAB is higher than that of AABB, indicating the aggregate or crossiinking kinetics of ABAB molecules by the cancelling of huge dipoles is slow because of the high energy barrier.
朱丹 粱翠芬 叶晓东 周克勳 沈健
南京师范大学,江苏省生物功能材料重点实验室,南京,210023 香港中文大学,化学系,香港 中国科技大学,高分子科学与工程系,合肥,230026
国内会议
杭州
英文
84-84
2014-09-24（万方平台首次上网日期，不代表论文的发表时间）