Isoprene rubber filled with silica generated in situ

Abstract

We modified synthetic isoprene rubber by means of the in situ generation of silica particles through the sol-gel process starting from tetraethoxysilane (TEOS) as an inorganic oxide precursor. Different reaction conditions were investigated with variations in the initial TEOS content, the reaction time of the sol-gel process, and the presence of a coupling/surfactant agent (octyltriethoxysilane). Organic-inorganic hybrid materials with a silica content up to 70 phr were obtained with the complete conversion of TEOS to silica for a long enough sol-gel reaction time. A very homogeneous dispersion of silica particles was observed in all cases together with a very good adhesion between the filler and matrix. The size of the in situ generated silica was controlled by the appropriate addition of octyltriethoxysilane. Swelling and extraction tests and dynamic mechanical analysis indicated that the vulcanization process of isoprene rubber was perturbed by the sol-gel process; this led to a slight decrease in the crosslinking degree. However, a significant reinforcing effect due to the presence of silica particles was observed for all of the investigated samples.

Influence of in situ -generated silica nanoparticles on EPDM morphology, thermal, thermomechanical, and mechanical properties

“…In this study, we investigated the preparation and characterization of EPDM filled with in situ‐generated silica nanoparticles. Our approach is similar to the investigations of Messori et al on the in situ generation of silica from TEOS into isoprene and EPDM rubbers with in situ‐generated silica. In this investigation, the reaction time of preparation was increased in order to improve the mechanical, thermomechanical, and thermal properties of the EPDM matrix.…”

“…The glass transition temperature ( T g ) decreased by 1–4°C for the silica‐containing samples (Table ), which is in agreement with the equilibrium swelling and gel content results, that indicated a decrease in the crosslinking density of the vulcanized rubber. Further explanations of this behavior was suggested by Messori et al , who investigated IR/SiO 2 composites generated through in situ synthesis, and by Ikeda et al [22], who investigated styrene‐butadiene rubber filled composites generated through in situ synthesis. Messori suggested that the decrease is due to the higher mobility of the polymer chains due to larger free volume caused by the presence of nonadhering nano‐objects inside the polymer bulk, while Ikeda suggested that the rubber may have been plasticized by residual oligomers from the sol–gel reaction.…”

Preparation and characterization of EPDM rubber modified with in situ generated silica

“…These compounds have functional groups suitable for improving filler-matrix interactions, thus allowing for a better silica dispersion and a higher mechanical reinforcement. 4 Messori et al recently published several papers on the in situ generation of silica from TEOS into isoprene rubber, [13][14][15] in particular reporting detailed studies of the interrelation between preparation conditions, structure and mechanical reinforcement. A similar approach was used in the present study on the preparation and characterization of ethylene-propylene-diene-monomer (EPDM) rubbers.…”

Effect of silane integrated sol–gel derived in situ silica on the properties of nitrile rubber

“…Several reports are available in the literature on the in situ generation of silica in the different rubber matrices such as natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), polydimethylsiloxane (PDMS), ethylene propylene diene monomer rubber (EPDM), butadiene rubber (BR), acrylic rubber (ACM), and chloroprene rubber (CR) . However, research on nitrile rubber (NBR) filled with in situ silica is very limited.…”