We present the effects of nanoparticle distribution on viscoelastic properties of a model polymeric system containing nano-silica to understand potential implications for binder applications. A model polymeric system consisting of equal percentages of immiscible mixtures of polyethylene glycol (PEG) and polytetrahydrofuran (PTHF) were synthesized with 0, 10, and 20 wt% nano-silica particles. Covalently bonding the particles to the polymer chains ensured the particles were not able to migrate between phases.  Mechanical properties of the resin were tuned through systematically changing the distribution of particles between the continuous and discontinuous phase. Through rheological experiments, it was discovered that there was significant hydrogen bonding between polymer chains and silica nanoparticles, allowing for large storage moduli prior to shearing. Once sheared, the storage modulus and viscosity decreased due to the Payne effect. A shear-dependent decrease in storage modulus and viscosity are significant because it eases processing of these solid rocket motor binders relative to current formulations.  We discuss the effects of particle distribution and their susceptibility to the Payne effects in the context of polymer binders.

Immiscible polymer formulations for tunable mechanical properties

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.