Factors Determining the Reinforcing Value of Fillers in Compounded Rubber.

Abstract

rubber. By reducing the particle size of a filler as dispersed in rubber the reinforcing effect is correspondingly increased. In presenting data on the reinforcing value of fillers it is therefore of greatest importance to state definitely the particle size of the material as present in the compound.Owing to an alignment of the particles during the milling and calendering operations, anisotropic fillers show abnormalreinforcingeffects.These effects are manifest, even though the filler is completely dispersed, and are not obliterated when the particle size is reduced to a state comparable with the finer fillers.The best reinforcing fillers are therefore those of smallest particle size, completely dispersed in and wet by the rubber and isotropic in particle shape. Any material, whatever its chemical nature, that fulfils these requirements will be a good reinforcing filler.

A predictive model for the mechanical behavior of particulate composites

“…Although the equations given here are written for the geometry used for our experiments, the approach is entirely general and could be used for experiments in shear, hydrostatic tension, or other configurations. Substituting the appropriate terms derived for this geometry results in the following equation: (4) where 6e = relative change in volume of sample 6A = free surface generated by dewetting If the appropriate linear elasticity equations are substituted fore, and the chain rule is used, all the differential terms can be put on a concentration basis. Taking the limits as the differen-L. L. Anderson and R. J .…”

“…Particulate composites subjected to large strains have a characteristic appearance of a n ellipsoidal vacuole surrounding each dewetted filler particle. The parameters affecting this failure such as particle size, filler concentration, and surface treatments, have been thoroughly investigated experimentally (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). It is uncertain whether the failure occurs by a cohesive mechanism away from the particle surface or by a n adhesive mechanism at the interface.…”

Dispersibility of Gas Black

“…This treated black disperses more rapidly than the same black not treated. Endres (2) postulates that the difficulty in milling Figure 8. Comparison of Ease of Dispersion at 113 d C. of Seven Channel Blacks contained in channel black assists dispersion.…”