An improved scheme for measuring 13C spin-lattice relaxation time: Targeting systems with marked difference in phase mobility or proton density
An improved scheme for measuring 13C spin-lattice relaxation time: Targeting systems with marked difference in phase mobility or proton density
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DOI：
10.1016/j.polymertesting.2019.105920
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发表时间：
2019-08
期刊：
影响因子：
5.1
通讯作者：
Ning Wang;Dandan Tang;Jie Shu
中科院分区：
文献类型：
--
作者：
Ning Wang;Dandan Tang;Jie Shu
提出了一种新的测量13C等低丰度核的自旋-晶格驰豫时间(T1)的方案--DP-Torchia方案。除了适用于传统13CT1方法的常见样品外，DP-Torchia还适用于含有具有明显不同局部迁移率或明显不同质子分布的磁区的混合物或材料。通过L-丙氨酸/金刚烷(ALA/ADA)混合物和聚乙烯醇/聚四氟乙烯(PVA/PTFE)聚合物共混物的试验，比较了逆回复法(IR)、扭转法和对苯二甲酸法(DP-Torchia)三种方法的性能。结果表明，DP-Torchia法与Torchia法和IR法的测量结果一致，Ala/Ada共混物的相对偏差小于3%，PVA/PTFE共混物的相对偏差小于1.5%。与传统方法相比，DP-Torchia方法所需的实验时间更少，可节省1/3的ALA/ADA共混物的传统测试时间，比传统的PVA/PTFE共混物的测试时间少6 h。与常用的反向恢复法和Torchia法相比，DP-Torchia法的实验时间更短，对被测样品的容忍度更高。这些良好的性能表明，DP-Torchia法有可能成为测量13CT1值的常规工具，特别是对于工业和科学研究中相迁移率或质子密度差异明显的材料。
A novel scheme, named DP-Torchia was developed to measure the spin-lattice relaxation time (T1) of low abundant nuclei, such as13C. Apart from the common samples that are suitable for the traditional13CT1methods, DP-Torchia is also designed for the mixtures or materials containing domains with markedly different local mobility or sharply distinct proton distribution. Through the tests of L-alanine/adamantane (Ala/Ada) mixture as well as the polymer blend of polyvinyl alcohol and polytetrafluoroethylene (PVA/PTFE), the performances of three methods are compared, including inverse-recovery (IR), Torchia and DP-Torchia. It is demonstrated that the results measured using DP-Torchia are in accordance with those of Torchia and IR methods, with the relative deviation of less than 3% for Ala/Ada mixture, while 1.5% for PVA/PTFE blend. Moreover, DP-Torchia consumes less experimental time than that of traditional methods, saving one-third of the traditional measuring time for Ala/Ada mixture, while consuming 6 h less measuring time than that of the traditional methods for PVA/PTFE blend. Compared with the common used methods, inverse-recovery and Torchia, DP-Torchia consumes less experimental time with more tolerance to the measured samples. Those favorable performances imply that DP-Torchia method has potential to become a routine tool for measuring13CT1values, especially for the materials with marked difference in phase mobility or proton density for industrial and scientific research.