Natural Rubber-Filler Interactions: What Are the Parameters?
Reinforcement of a polymer matrix through the incorporation of nanoparticles (fillers) is a common industrial practice that greatly enhances the mechanical properties of the composite material. The origin of such mechanical reinforcement has been linked to the interaction between the polymer and filler as well as the homogeneous dispersion of the filler within the polymer matrix. In natural rubber (NR) technology, knowledge of the conditions necessary to achieve more efficient NR-filler interactions is improving continuously. This study explores the important physicochemical parameters required to achieve NR-filler interactions under dilute aqueous conditions by varying both the properties of the filler (size, composition, surface activity, concentration) and the aqueous solution (ionic strength, ion valency). By combining fluorescence and electron microscopy methods, we show that NR and silica interact only in the presence of ions and that heteroaggregation is favored more than homoaggregation of silica-silica or NR-NR. The interaction kinetics increases with the ion valence, whereas the morphology of the heteroaggregates depends on the size of silica and the volume percent ratio (dry silica/dry NR). We observe dendritic structures using silica with a diameter (d) of 100 nm at a ∼20-50 vol % ratio, whereas we obtain raspberry-like structures using silica with d = 30 nm particles. We observe that in liquid the interaction is controlled by the hydrophilic bioshell, in contrast to dried conditions, where hydrophobic polymer dominates the interaction of NR with the fillers. A good correlation between the nanoscopic aggregation behavior and the macroscopic aggregation dynamics of the particles was observed. These results provide insight into improving the reinforcement of a polymer matrix using NR-filler films.
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405, Orsay, France.|Manufacture Française des Pneumatiques Michelin , 23 place des Carmes Déchaux, 63040 Clermont Ferrand Cedex 9, France.
Alan Jenkin
AJ
Chan
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405, Orsay, France.
Karine
K
Steenkeste
INRA AgroParisTech, Micalis, UMR 1319, 91300 Massy, France.
Alexis
A
Canette
Manufacture Française des Pneumatiques Michelin , 23 place des Carmes Déchaux, 63040 Clermont Ferrand Cedex 9, France.
Marie
M
Eloy
Manufacture Française des Pneumatiques Michelin , 23 place des Carmes Déchaux, 63040 Clermont Ferrand Cedex 9, France.
Damien
D
Brosson
Manufacture Française des Pneumatiques Michelin , 23 place des Carmes Déchaux, 63040 Clermont Ferrand Cedex 9, France.
Fabien
F
Gaboriaud
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405, Orsay, France.
Marie-Pierre
MP
Fontaine-Aupart
D006244:Hardness; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D010316:Particle Size; D012408:Rubber / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D014867:Water; D012822:Silicon Dioxide; D012408:Rubber