Abstract
The thermal relaxation of crystalline and amorphous polyethylene terephthalate, PET, i.e. the enthalpic relaxation or physical ageing, has been measured using a range of thermal analytical techniques, namely DSC, DMTA, and DETA. While the relaxation is associated with the amorphous regions, in general, these are constrained by the presence of crystalline regions out of proportion to the amounts present, such that the glass transition temperature T g is raised to higher values and the transition itself broadened. The change in specific heat associated with the transition is also reduced and measurement of the T g of partially crystalline material by DSC becomes difficult. Chain mobility is greatly reduced and this has a marked effect in reducing the rate of enthalpic relaxation but not eliminating it entirely.
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.
