The Role of Polymer Chain Stiffness and Guest Nanoparticle Loading in Improving the Glass Transition Temperature of Polymer Nanocomposites.

The impact of polymer chain stiffness characterized by the bending modulus ( k θ ) on the glass transition temperature ( T g ) of pure polymer systems, as well as polymer nanocomposites (PNCs), is investigated using molecular dynamics simulations. At small k θ values, the pure polymer system and respective PNCs are in an amorphous state, whereas at large k θ values, both systems are in a semicrystalline state with a glass transition at low temperature. For the pure polymer system, T g initially increases with k θ and does not change obviously at large k θ . However, the T g of PNCs shows interesting behaviors with the increasing volume fraction of nanoparticles ( f NP ) at different k θ values. T g tends to increase with f NP at small k θ , whereas it becomes suppressed at large k θ .