Abstract
AbstractThe characteristic time periodicity and the spatial characteristic wavelength of extrusion flow instabilities of a linear and a branched commercial polyethylene (PE) are characterized via capillary rheology, optical analysis and modeled. The two investigated polyethylenes have the similar weight average molecular weight (Mw). The characteristic time periodicity is obtained and compared using three methods: (i) a highly sensitive pressure slit die, (ii) a new online optical analysis method based on the construction of a space–time diagrams, and (iii) an offline transmission polarization microscopy. In addition, the spatial characteristic wavelength λ is quantified by offline transmission polarization microscopy. The characteristic time periodicity of the extrusion flow instabilities follows a power law behavior as a function of apparent shear rate to a power of −0.7 for both materials,. A qualitative model is used to predict the spatial characteristic wavelength of extrusion flow instabilities as well. It is found that the characteristic spatial wavelength λ and the characteristic time periodicity have an Arrhenius temperature‐dependent behavior.
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.
