POLYMER-FILLER INTERACTIONS IN RUBBER REINFORCEMENT

The reinforcement of elastomers by finely divided fillers, particularly carbon black and silica, is fundamental to the rubber industry. Optimal reinforcement appears to involve both physical and chemical interactions. From a consideration of the effects of particle size as such, it appears that reinforcement, in the sense of tensile enhancement, will occur with any very finely divided filler. Physical factors prevent escape of the polymer from the filler surface (vacuole formation) but allow stress delocalization through interfacial slippage. Occasional stronger bonds may be introduced advantageously to facilitate dispersion, reduce particle/ particle interactions, and optimize practical properties relating to resilience and durability. Several lines of evidence suggest that only a minor amount of strong bonding is necessary or desirable, such that polymer/filler slippage can occur, under stress, over most of the interfacial area. © 1990 Chapman and Hall Ltd.