On the key role of SiO^sub 2^@POSS hybrid filler in tailoring networking and interfaces in rubber nanocomposites

• Published in: Polymer testing Vol. 65; p. 429
• Main Authors: Redaelli, Matteo, D'Arienzo, Massimiliano, Brus, Jiri, Di Credico, Barbara, Geppi, Marco, Giannini, Luca, Matejka, Libor, Martini, Francesca, Panattoni, Francesco, Spirkova, Milena, Šlouf, Miroslav, Scotti, Roberto, Morazzoni, Franca
• Format: Journal Article
• Language: English
• Published: Barking Elsevier BV 01-02-2018
• Subjects: Bonding strength; Butadiene; Crosslinking; Inspection; Nanocomposites; Nanoparticles; Network formation; NMR; Nuclear magnetic resonance; Rubber; Silica; Silicon dioxide
• ISSN: 0142-9418; 1873-2348

The present study provides a comprehensive investigation at the micro and nanoscale of the interface between hybrid Si02@POSS nanofiller, where silica nanoparticles (NPs) and POSS nanocagcs arc intimately interconnected, and Styrene Butadiene Rubber (SBR). SEM and AFM inspection and, more in depth, solid state 1H NMR revealed a remarkable fraction of rigid rubber close to the Si02@POSS surfaces, which increases with the curing temperature. Instead, a reduced amount of immobilized rubber was detected for SBR/Si02 + POSS nanocomposites, obtained by simply mixing SBR, Si02 and POSS. The results allowed us to propose a model for the network formation in C-SBR/Si02@POSS. This is based on the progressive activation by dicumylpcroxidc (DCP) of the methacryl functionalities of POSS nanounits which, being closely connected to Si02 NPs in Si02@POSS, promote crosslinking in proximity of the filler surfaces, and lead to the generation of a tight network strongly bonded to the rubber chains.