Abstract
AbstractChain scission was observed during the crystallization of p‐xylene in dilute polystyrene solutions. Degradation yields were determined by gel permeation chromatography, as a function of the number of freeze‐and‐thaw cycles, polymer concentration, and initial polymer molecular weight (M). The rate constant for chain scission Kc increases with the polymer chain length, from 0.021%/cycle at M = 110·103 to 4.7%/cycle at M = 8.5·106. Over the two decades range of investigated molecular weights, Kc follows an empirical scaling law of the form Kc ∼ (M − Mlim)1.17578, where Mlim is a limiting molecular weight ≅ 29,000 g. mol−1 below which no degradation could be induced. Some propensity for midchain scission was detected, although this tendency was much weaker in comparison to flow‐induced degradation.A chain scission model based on crack propagation failed to reproduce the experimental results. To explain the observed dependence of Kc with the square of the radius of gyration, an interfacial stress transmission mechanism between the crystallization fronts and the polymer coil has been proposed. © 1994 John Wiley & Sons, Inc.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Polymer Science Part B: Polymer Physics
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.