(670e) Impact of Sol Molecular Weight and Network Architecture On the Mechanical Properties and Fracture Behavior of Elastomeric Polysiloxanes

Polymer gels have the potential to be rapidly implemented into a wide range of applications as the result of the ability to tailor the mechanical, electrical, and optical properties. Polymer gel properties are typically tuned by changing the network polymer chemistry, solvent type, solvent loading, or through filler addition. Polymer and solvent molecular weight and architecture can also have a critical impact on the performance. However, implementation of polymer gels into many practical applications has been limited by their relatively poor mechanical toughness. In this report, we investigate the impact of the non-reactive soluble material (sol) molecular weight and loading on the mechanical properties and fracture behavior of the gel. Specifically, the impact of chain entanglements when the sol molecular weight is increased above the molecular weight of entanglement (MW_ENT). Sols with molecular weights higher than MW_ENT exhibit a decreased impact on the modulus with loading, attributed to the sol's ability to entangle with the network and contribute to the stiffness. In addition, gels containing high molecular weight sols have exhibited higher energy release rates during tear testing. We are currently extending this work to additional polymer network and sol architectures.