Hybrid SiO₂@POSS nanofiller: a promising reinforcing system for rubber nanocomposites

Abstract

A novel hybrid nanofiller, SiO 2 @POSS, where the silica nanoparticles (NPs) and the POSS belong to the same functional structure, has been synthesized by grafting different loadings of OctaMethacrylPOSS onto silanized commercial SiO 2 , using a surface reaction mediated by dicumylperoxide (DCP). The peroxide, besides anchoring the nanocages onto the silica surface, ensures the presence of methacryl functionalities in the final structure, which are still available for cross-linking reactions with a polymer host. The hybrid SiO 2 @POSS NPs were used to prepare, by ex situ blending, SBR nanocomposites. The dynamic-mechanical analysis performed on the cured SBR/SiO 2 @POSS composites indicated that the presence of POSS induces a remarkable increase of modulus either at low or at high strain, and a considerable decrease of hysteresis. This has been associated with the peculiar hybrid structure of the SiO 2 @POSS filler, in which silica NP aggregates are partially interconnected and surrounded by a thin shell of POSS nanounits which, thanks to their high number of reactive functionalities, promote the formation of ''sticky regions'' among the silica aggregates and, consequently, a tight filler network wherein rubber is immobilized. This grants a relevant reinforcement and increased hysteretic properties, suggesting SiO 2 @POSS as a promising filler system for decreasing the energy loss under strain and for leading to a potential reduction of filler utilization in rubber composite formulations.

SiO2/Ladder-Like Polysilsesquioxanes Nanocomposite Coatings: Playing with the Hybrid Interface for Tuning Thermal Properties and Wettability

“…These inorganic polymeric materials can provide both remarkable thermomechanical properties and water repellency, owing to the presence of tunable peripheral organic groups, which may also offer compatibility, dispersion stability, and reactivity [28][29][30][31]. PSQs can be classified into either random or random branched structures [32], polyhedral oligomeric silsesquioxanes (POSS) [33][34][35][36][37][38], and fully condensed ladder-like polysilsesquioxanes with double-stranded backbones (LPSQs) [39,40].…”

On the key role of SiO2@POSS hybrid filler in tailoring networking and interfaces in rubber nanocomposites

“…SiO 2 @POSS hybrid filler was prepared by the double-step functionalization procedure reported in the previous work [12]. Firstly, SiO 2 (30 phr, i.e.…”

“…In this respect, we have recently reported [12] on the promising properties of polyhedral oligomeric silsesquioxanes (POSS) [13][14][15] used as molecular nanofillers together with SiO 2 nanoparticles (NPs).…”

“…Moreover, comparing the performance of SBR/SiO 2 @POSS to that of composites prepared by mixtures of SiO 2 and OctaMethacrylPOSS in the polymer matrix (SBR/SiO 2 +POSS), showed that the functionalization of silica surface with POSS determines a more positive effect on the modulus and reduces the hysteresis. These properties have been associated so far with the peculiar hybrid structure of SiO 2 @POSS filler, in which silica NPs aggregates are partially interconnected and surrounded by a thin shell of POSS nanounits which, thanks to their high number of reactive functionalities, seem to promote the formation of "sticky regions" among the silica aggregates and, consequently, a tight filler network wherein rubber is immobilized [12].…”

Hybrid Interface in Sepiolite Rubber Nanocomposites: Role of Self-Assembled Nanostructure in Controlling Dissipative Phenomena

“…Over the last decades, research on nanocomposites (NCs) has stimulated enormous efforts in the development of improved functional properties [1,2,3]. Among NCs, the production of high performance polymeric NCs (PNCs) by incorporation in the rubber matrix of different nanoparticles, such as carbon black, carbon nanotubes, nanosilica, clays, layered silicates, and layered double hydroxides, strongly depends on their good dispersion in rubber [4,5], due to the interfacial nanofiller/polymer interactions and to the formation of a filler percolating network [6,7,8], which enable the material to support large dynamic loads over millions of load cycles [9,10].…”