Thermomechanical properties of silica-polyacrylic nanocomposites

Abstract

The synthesis of inorganic/organic nanocomposite systems, well known as hybrid materials, represents a new class of polymeric materials, which combine properties of inorganic particles, such as barrier, optical, catalytic and conductive properties, among others, with flexibility and transparency of the organic polymer matrix, being easily processable. They could be applied in a diversity of areas such as textiles, inks, adhesion, biomaterials, paints, adhesives, and electronics [1–2]. Within the inorganic materials, silica nanoparticles which present excellent properties, such as high mechanical strength, thermal and chemical stability, and high surface area, have been widely incorporated into a polymer matrix to prepare polymer/silica hybrid materials [3–4]. It is reported that the quantity and the dispersion of nano-SiO₂ in the polymer matrix have a real effect on the properties of the final materials [5–6].

In this work, hybrid silica/poly(butyl acrylate-methyl methacrylate-acrylic acid) (SiO₂/P(BA-MMA-AA)) were synthesized via in situ semi-batch emulsion polymerization. The results showed that this process was produced with high monomer conversion and low formation of agglomerates. The thermomechanical behavior of the films obtained from latexes was characterized by using thermogravimetric analysis, differential scanning calorimetry, and tensile test. The nanocomposite films displays significantly improved mechanical and thermal properties over its pure polymer film, and also presents almost the same high transparency.