An Investigation of Mechanical Properties of Polyurethane Nanocomposites with Various Silicas: Experimental Study and Modeling of Finite Deformation Response

Stepwise surface modification of mesoporous silica and its use in poly(urethane‐urea) composite films

“…20,25,56 Additionally, long chains on the particle surface favor linking the particles to the matrix physically, improving the particle dispersion. 17,18 Also, the affinity of particles to matrix is a significant issue determining particle dispersion and composite properties. The presence long-chain moieties on G2-silica particles with high NH content, which makes the particles more compatible with polar PUUs, leads to a better dispersion of particles, and thereby enhanced mechanical properties.…”

“…Particles would limit chain flexibility and mobility favoring mechanical properties. 17,[20][21][22][23][24][25][26] However, above an optimum loading, a decline in the mechanical performance would occur due to particle agglomeration. Particle aggregates act as stress concentration points, deteriorating the mechanical properties.…”

“…Surface modification containing hyperbranched structures (dendrimers) on silica has been considered, especially for adsorption purposes. The presence of long chains on the silica surface causes more physical linking and entanglement between particles and polymer, which is favorable for better particle dispersion 17,18 . In our previous study, this approach was used on fumed silica for gas separation application 19 .…”

“…The presence of long chains on the silica surface causes more physical linking and entanglement between particles and polymer, which is favorable for better particle dispersion. 17,18 In our previous study, this approach was used on fumed silica for gas separation application. 19 Modified nanoparticles having a hyperbranched structure containing amine moieties were used to prepare mixed-matrix membranes based on polyurethane (PU).…”

“…Silica can enhance the tensile modulus and strength of PU by limiting the chain mobility of the polymer. 17,[20][21][22][23][24][25][26] PU consists of two domains: soft domain including polyols (polyesters or polyethers) and hard segments (diisocyanate and a diamine or diol chain extender to create urea and urethane groups, respectively). [27][28][29] The incompatibility between the hard segments (more polar domains) and soft ones (less polar domains) results in microphase separation in the PU structure, which affects morphology, mechanical performance and physical properties of PU.…”