Natural rubber‐carbon black coagulation: Following the nanostructure evolution from a colloidal suspension to a composite

Abstract

AbstractMaking elastomeric composite materials via heteroaggregation of a binary colloidal suspension of Natural Rubber (NR) latex and Carbon Black (CB) filler is an interesting production method to obtain an efficient dispersion in the polymer matrix. This study successfully employs an original approach of field emission scanning electron microscopy (FESEM) to investigate for the first time the nanostructure evolution of a coagulum originated from the aggregation of NR globules with CB filler in suspension. More specifically, we exploited a chemical fixation method allowing simultaneous acquisition of backscattered electron (BSE) and secondary electron (SE) imaging modes. Additionally, the role of external physical stresses, like mechanical shear and sonication was also investigated in terms of structural effect induced on the formed coagulum at the nanoscopic scale. Our results highlight destabilization of NR globules, either induced by direct interaction with small CB aggregates or governed by solvent evaporation. Reduction in the size of CB agglomerates, obtained using sonication, highly improved filler distribution and confirmed that the size of CB aggregates is an important parameter responsible for the destabilization of NR globules.