Linear high molecular weight polymers undergo central scission in strong flows due to
buildup of stress from fluid drag. An alternative to linear architecture is the star branched polymer that
shows higher shear stability against such scission. We consider two six-arm star polymers differing in
the connectivity of the arms at the core. The first is a fused-core star PMMA, where the arms are
interconnected at a triphenylene core, with the multiple bonds therein supporting one another against
possible tensile fracture. The second is a linear-core star PMMA, containing linearly linked single bonds
within the core as potential fracture sites under tensile stress. Their stress-induced scission tendency is
analyzed during planar elongational flow of their dilute solutions in dibutyl phthalate in a cross-slot
flow cell. We find that scission of the star PMMA at the arms dominates their degradation behavior, and
both the linear-core and fused-core star PMMAs show similar flow-induced scission. These results are
analyzed first in terms of the critical-stress-to-fracture (CSF) and then in terms of scission kinetics as
described by the thermally activated barrier to scission (TABS). The experimentally observed scission
kinetics of the arms can be represented by the TABS model, but a description of the core scission appears
to demand consideration of several possible conformations of the branched polymers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.