含U形结构单元的聚萘二甲酸乙二醇酯的等温结晶行为研究

Research on Isothermal Crystallization Behavior of Poly (ethylene naphthalate) Containing U-turn Unit

以1,8-萘二甲酸二甲酯为共聚单体,与2,6-萘二甲酸二甲酯和乙二醇进行共聚,得到U形1,8-萘结构单元含量分别为2%和5%(质量分数)的聚萘二甲酸乙二醇酯共聚物。DSC测试表明,与聚2,6-萘二甲酸乙二醇酯(PEN)相比,含有1,8-萘结构单元共聚物的Tg和Tm略有降低,而1,8-萘U形结构单元的引入可以增加PEN的热结晶速率。采用Avrami模型得到了PEN及共聚物的Avrami指数n、结晶速率常数K以及半结晶时间t1/2。PEN、含2%1,8-萘结构单元共聚物和含5%1,8-萘结构单元共聚物的半结晶时间t1/2分别为2.62min、2.09min和1.24min,表明U形1,8-萘结构单元的引入确实可以增加聚合物的结晶速率。

Poly（ethylene naphthalate） copolymers containing 2% or 5% U-turn 1,8-naphthalate structural units were prepared via copolymerization of methyl 1,8-naphthalate, methyl 2,6 naphthalate, and glycol. DSC analysis shows that the copolymers have very good thermal behaviors, their Tg and Tm are slightly lower than those of PEN. Data shows that incorporation of 1,8-naphthalate structural units could increase the hot crystallization rate of the copolymers. The Avrami exponent n, half crystallization time tl/2, and crystallization rate constant K were obtained via Avrami equation. The half crystallization times t1/2 of PEN, the copolymer scontaining 2% and 5% U-turn 1,8-naphthalate units are 2.62 min, 2.09 min and 1.24 min, respectively. This indicates that the introduction of U- turn unit could obviously increase the crystallization rates of polymers.