Desenvolvimento e caracterização de blendas acrílicas e estirênicas com MBS

Abstract

This study investigated the influence of the chemical structure of methyl methacrylate-butadiene-styrene (MBS) copolymer on physical blends with poly(methyl methacrylate) (PMMA), polystyrene (PS) and styrene-acrylonitrile copolymer (SAN). The polymer blends were produced in a twin-screw extruder and then the specimens were manufactured by injection molding. The results of the optical properties showed a transparency higher than 75% and 90%, respectively, for the blends with PS and SAN. The blends developed with PMMA presented opacity for all compositions. Fourier transform infrared spectroscopy (FTIR) showed the characteristic bands of the specific chemical structures of the polymer blends. The spectra did not show any conformational or structural changes in the polymer blends, and no new absorption bands were observed. Thermogravimetric characterization (TG) showed that the blends with styrenic matrices (PS and SAN) presented greater thermal stability than the acrylic matrix blend (PMMA). Mechanical characterization showed that the blends with 30% MBS presented a substantial gain in the elastic modulus. The rheological results in the linear viscoelasticity region showed significant changes in the terminal region related to the presence of MBS. Morphological characterizations showed the immiscibility of the PMMA/MBS and SAN/MBS blends, evidenced by the presence of dispersed phase domains, while the PS/MBS blend was miscible.