Abstract
AbstractSpin‐lattice relaxation times and nuclear Overhauser enhancements (NOE) for 13C nuclei in copolymers of acrylonitrile and vinylidene chloride were measured at 20.1 and 67.9 MHz. In the CCl2 region of the spectrum T1 and NOE values of the various resonances are equal within experimental error and are invariant to changes in composition. The T1 and NOE values of the CCl2 region, however, are not equal to those of the CH or CN region. As a result compositions cannot be calculated by direct comparison of the areas in the CCl2 region and either the CH or the CN region. Discrepancies can be corrected for the CH resonances by multiplication of the area by an empirical constant. A similar constant for the CN region is composition‐dependent at 20.1 and 67.9 MHz. A chemical shift anisotropy mechanism is postulated as important for relaxation of the CN resonances. The overall influence of variable T1 and NOE values on quantitative determination of polymer composition is considered.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Polymer Science: Polymer Chemistry Edition
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
