Background:
This work presents the preparation and characterization of the polymeric nanocomposites based on
methyl methacrylate (MMA), ethyl acrylate (EA), and natural and modified clays. The clays used to prepare the composite
were natural green bentonite (GBC-N) and organophilic clays modified with ammonium quaternary salts: Praepagen (GCBP), Dodigen (GCB-D) and Praepagen/Dodigen mixture 1:1 in weight (GCB-P/D).
Objective:
The experimental studies focused on the evaluation of the effect of clays (in natura and chemically modified) on
the final quality of the polymeric nanocomposites containing around 3 wt%. of clay nanocharges in association with MMA
to produce poly(methyl methacrylate)/clays; and MMA/EA to form poly(methyl methacrylate-co-ethyl acrylate)/clays.
Materials and Methods:
The poly(methyl methacrylate)/clay and poly(methyl methacrylate-co-ethyl acrylate)/clay
materials were synthesized through mass-suspension polymerization process. The natural and modified green bentonite
clays were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), Differential scanning calorimetry
(DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) analyzes to understand its effect on
the basal spacing, d001 (compared to the pure clay), as a result of cation exchange step, in which also improved the thermal
efficiency of the final nanocomposites.
Results:
The proper incorporation of MMA and MMA/AE monomers between the layers of natural and modified clays
occurred through in situ mass-suspension polymerization, leading to a successful exfoliation of clay layers during the growth
of the polymer chains.
Conclusion:
The IR, SEM, TGA and DSC analyzes confirmed the improvement in the thermal property of the composites
compared to polymers formed in the absence of clays. The experimental results are very promising, indicating that the
experimental protocol based on the in situ formation of polymer nanocomposites by the using sequential mass-suspension
polymerization consist of an interesting tool.
