Abstract
Abstract Size Exclusion Chromatography (SEC) or Gel Permeation Chromatography [GPC] was used to determine the molecular weight and molecular weight distribution of butyl rubbers. Quantitative data were obtained by viscometry, and by the use of narrow distribution polyisobutylene (PIB) standards for calibration. The application of the Universal Calibration Principle, which uses readily available narrow distribution polystyrene (PS) standards, relies on the knowledge of the Mark-Houwink-Sakurada constants, K and α, for PIB or butyl rubber (the copolymer of isobutylene and isoprene containing 1–3 mol% of the latter). Comparison of narrow PIB and narrow PS calibrations led us to the selection of KPIB=2×10−4 dl/g and α=0.67, the constants published by the American Standards Corporation for PIB in tetrahydrofuran (THF) at 30°C, as best fit values. The weight average molecular weight [Mw] of various samples of commercially produced butyl rubber determined by using the Universal Calibration Principle with the selected constants, agreed well with those measured by viscometry. Other published K and α values yielded a poorer agreement.
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 callDisclaimer: 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.
