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This study investigates the effect of adding oligomers on the rheological properties of polymer nanocomposite melts with the goal of enhancing the processability of nanocomposites. The scaling analysis of plateau modulus (GN) is used in understanding the complex mechanical behavior of entangled poly(methyl acrylate) (PMA) melts upon oligomer addition. Increasing the oligomer amount led to a decrease in GN and an apparent degree of entanglement (Z) in the neat polymer melt. The particle dispersion states at two particle loadings with oligomer addition are examined in transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS). The dilution exponent is found unchanged at 7 and 17 vol% particle loadings for the well‐dispersed PMA‐SiO2 nanocomposites compared to the neat PMA solution. These findings suggest that attractive particles with strong interfacial layers do not influence the tube dilution scaling of the polymer with the oligomer. To the contrary, composites with weak polymer‐particle interfaces demonstrate phase separation of particles when oligomers are introduced and its exponent for tube dilution scaling reaches 4 at a particle loading of 17 vol%, potentially indicating that network‐forming clusters influence chain entanglements in this scenario. [ABSTRACT FROM AUTHOR]

This work is designed to explore the effect of entanglements and particle loading on viscoelastic properties of crosslinked polymer nanocomposites. The entangled and unentangled poly(methyl acrylate) composite networks were synthesized and characterized in linear rheology. We found that the elastic moduli and crosslinking degree of entangled composite networks were unaffected with particle loading. For the unentangled composite networks, both elastic moduli and crosslinking degree enhanced with particle loading. The reinforcement factor analyzed with the recovery of modulus after large deformation indicated that entangled composite networks fully recovered their initial moduli, suggesting the high entanglements can sustain large deformation and maintain their initial chain conformation even at high particle loadings. The unentangled networks did not recover their initial storage moduli after large deformation, posing the non-deformability of the highly crosslinked networks. [Display omitted] • Entangled polymer crosslinking in nanocomposites for enhanced reinforcement is reported. • Particles can enhance crosslinking degree in unentangled (permanent) polymer networks. • Entangled composite networks can fully recover their initial moduli after nonlinear deformation. • The first comparison of unentangled and entangled composite networks. [ABSTRACT FROM AUTHOR]