【作者】 张莉莉； 林伟信； 陈群；

【Author】 Zhang Lili Lin Weixin Chen Qun (Analytical Center & the key Laboratory for Optics and Magnetic Resonance Spectroscopy,East China Normal University,Shanghai 200062)

【机构】 华东师范大学分析测试中心教育部光谱学与波谱学重点实验室；

【摘要】 <正>随着硬件技术的进步,魔角旋转(MAS)的转速逐步提高,使得基于 MAS 的固体高分辨~1H 谱越来越容易实现,应用范围也越来越广。但是,~1H MAS 实验中仍然有许多基本问题有待研究。最近我们在用~1H MAS 谱研究一些半晶高分子材料时发现,在所获得的~1H MAS 谱中存在着被窄化的中心线、旋转边带以及宽包三种不同的谱峰结构,本文将主要针对这三种不同的谱峰结构和高分子的聚集态结构的对应关系进行研究和讨论。更多还原

【Abstract】 It was observed that ¹H MAS NMR spectrum of high density polyethylene（HDPE）comprises of three parts:a broad component,a narrow central line and spinning side bands.The line width of the spinning side bands increases with the its order.“Dipolar-filter” was applied to eliminate the contribution of the crystalline region of HDPE from ¹H MAS spectrum and the characteristics of the resulted spectrum suggested that in the original ¹H MAS spectrum acquired without “dipolar-filter”,the broad component are directly associated with the crystalline region,while the narrow central line and the spinning side bands include contribution of both crystalline and amorphous regions of HDPE,By employing a new pulse sequence which can be used to selectively measure 1H T₂ of the crystalline region in different depths from the crystalline-amorphous interface, it was demonstrated that there exist a distribution of mobility in the crystalline region of HDPE.It is believed that the relatively mobile part of the crystalline region contributes to the narrow central line and spinnin,g side bands in ¹H MAS spectrum of HDPE.更多还原