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

Abstract

Making 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.

Nanostructural Evolution of Natural Rubber/Silica Nanoparticle Coagulation from Binary Colloidal Suspensions to Composites: Implications for Tire Materials

“…For the latter, it was recently reported that when CB aggregates are in contact with NR globules, coalescence of the latter was promoted. 27 3.2. NR−SiO 2 NPs Heteroaggregates: Structural Evolution during Drying and Shearing.…”

“…The sample preparation and description of the shearing module used in these experiments were described in detail elsewhere. 27 Briefly, the SiO 2 NPs binary colloidal suspension was placed between two microscopy coverslips (with a controlled gap width of 500 μm) well suited for the application of controlled shear. This was obtained using a commercial device called RheOptiCAD (CAD instrument).…”

“…This lack of globules coalescence in the liquid state presents one of the main differences with NR-carbon black systems, obtained with a similar protocol. For the latter, it was recently reported that when CB aggregates are in contact with NR globules, coalescence of the latter was promoted 27 .…”

Novel IP2C sensors with flexible electrodes based on plasma-treated conductive elastomeric nanocomposites

“…This solution was again sonicated for better dispersion of the additives, with a 600 W probe ultrasound for 25 min in an ice bath. The suspension formed was poured into Petri dishes in volumes of 50 ml to produce films in a casting-like process [48,49]. The plates were then placed in an oven with air circulation at 50 • C and left for 48 h for drying and rubber maturation.…”