Title:Mass-suspension Polymerization Process as an Efficient Tool to Produce Polymer/Clay Nanocomposites
Volume: 4
Issue: 2
Author(s): Mariaugusta F. Mota, Thainá Araruna, Nathália M. Campelo, Meiry Gláucia F. Rodrigues, Gabriella R. Ferreira and Fabricio Machado*
Affiliation:
- Institute of Chemistry, University of Brasilia, University Campus Darcy Ribeiro, CEP 70910-900, Brasília, DF,Brazil
Keywords:
Clay organophilization, green bentonite, smectite, methyl methacrylate, ethyl acrylate, copolymerization.
Abstract:
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 (GCB-P), 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 nature 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.
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) analyses to understand its effect on the basal spacing,
d001 (compared to the pure clay), as a result of cation exchange step, which also improved the thermal
efficiency of the final nanocomposites.
Results: The proper incorporation of MMA and MMA/EA 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 analyses 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 using sequential mass-suspension polymerization consisting of
an interesting tool.