期刊
CELLULOSE
卷 26, 期 17, 页码 8993-9003出版社
SPRINGER
DOI: 10.1007/s10570-019-02718-0
关键词
Crystallinity; Cellulose; MAS; C-13 NMR; C-13 T-1; Cross-polarization
资金
- Chalmers University of Technology
- Stiftelsen Nils och Dorthi Troedssons forskningsfond [867/15]
- Knut and Alice Wallenberg Foundation
The crystallinity of cellulose has a strong impact on various material properties. Over the years, many methods have become available to estimate the crystallinity. The purpose of this work was to revise existing NMR-based methods and to introduce a complementary NMR method related to the C-13 T-1 relaxation time. The C-13 T-1 differs by an order of magnitude for amorphous and crystalline polymers among them cellulose. We have utilized the signal boost of H-1-C-13 cross polarization and the difference in C-13 T-1 as a filter to calculate the degree of crystallinity. The evaluation of the method is based on the difference in peak integrals, which is fed into a simple equation. The method was applied to five cellulosic samples of different nature and compared the obtained degree of crystallinity with the degree estimated from deconvoluted X-ray scattering patterns. Furthermore, an attempt has been made to give a basic understanding on the origin of CP enhancement in order to validate various proposed NMR methods. With the recent progress of NMR equipment, the presented method can be automatized and applied to a series of samples using a sample changer.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据