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利用铜离子(Cu2+)对聚氧乙烯(PEO)的配位作用所形成的对分子链运动的束缚,研究了链段受限下PEO的结晶和熔融行为.首先利用宽频介电松弛谱(BDS)对受限条件下PEO的松弛行为进行表征,结果表明,加入铜离子后PEO的β-过程和γ-过程的特征松弛时间都变长,说明PEO的链段协同运动和主链扭转运动都变得更加困难;松弛时间为评价受限程度提供了定量的依据.DSC的测试结果表明,受限条件下PEO的玻璃化转变温度(Tg)升高,同时出现冷结晶现象,说明Cu2+配位作用确实对PEO的链段运动产生了束缚作用;同时PEO的结晶度和熔点都随着铜离子含量的提高而降低.WAXD结果表明,CuBr2在共混物中没有发生结晶,同时PEO的晶型没有发生改变.利用AFM进一步研究了PEO/CuBr2共混物薄膜的结晶形貌,发现在不同Cu2+含量的共混物中PEO都形成伸直链晶体,片晶厚度没有变化,说明熔点的降低并非是片晶厚度变化所导致.但是AFM的结果却显示螺位错晶体的数量随着Cu2+含量的提高明显增加.可以认为,在Cu2+配位受限下的PEO体系中,晶体缺陷应是引起熔点下降的主要原因,和金属等其它晶体材料的情况有着类似效应.
The crystallization and melting behavior of PEO with limited segments were studied by the binding of copper ions (Cu2 +) to the movement of molecular chains formed by the coordination of polyoxyethylene (PEO). Firstly, ) On the relaxation behavior of PEO under confined conditions, the results show that after the addition of copper ions PEO β-process and γ-process characteristics of the relaxation time are longer, indicating PEO chain synergistic movement and the main chain of torsional movements are The relaxation time provides a quantitative basis for the evaluation of the degree of limitation.DSC test results show that under limited conditions, the glass transition temperature (Tg) of PEO increases, while the cold crystallization phenomenon, indicating Cu2 + coordination The effect of PEO on the chain segment did indeed play a binding role; at the same time, the crystallinity and melting point of PEO decreased with the increase of copper ion content.WAXD results showed that there was no crystallization of CuBr2 in the blend and the crystal form of PEO No change was observed.Finally, the morphology of PEO / CuBr2 blends was studied by AFM. It was found that PEO formed straight chain crystals in the blend with different content of Cu2 +, and the thickness of lamella did not change, indicating that the decrease of melting point was not Is the lamella thickness However, the results of AFM show that the number of dislocation crystals increases with the increase of Cu2 + content.It is believed that the crystal defects should be the main reason for the decrease of melting point in PEO with Cu2 + coordination limitation , And metal and other crystalline materials have a similar effect.