Abstract
Abstract A basic study of the kinematics and dynamics of the double bubble tubular film process as applied to polyethylene terephthalate (PET), poly p phenylene sulfide (PPS), polycarbonate (PC) and low density polyethylene (LDPE) is presented. The stability of the four resins was investigated for both a single bubble tubular film and a second bubble of a double bubble process. For the single bubble the LDPE is very stable and the PET, PPS and PC have more limited regions of stability with periodic axisymmetric instabilities near blowup ratios of unity and helical instabilities at higher blowup ratios. It is found that in the first bubble the PC vitrifies to a glass, PET and PPS crystallize to 4 to 9% levels and LDPE to nearly 50%. In the second bubble it is found possible to operate in a stable manner with a heated air ring and stable bubble for PET and PPS but not PC and LDPE. In the second bubble PET and PPS show substantial levels of increase of crystallinity. This is not the case for PC and LDPE. It appears that a strain hardening process such as crystallization is necessary for stability of the second bubble. Stress fields in the second bubble are computed using membrane theory.
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.
