Study of optical transparency in acrylic and styrenic blends with MBS
Acrylic polymers; styrenic polymers; methyl methacrylate-butadiene-styrene copolymer; optical transparency
The aim of this work was to investigate the influence the chemical structure of the methyl methacrylate-butadiene-styrene copolymer (MBS) in physical mixtures with poly(methyl methacrylate) (PMMA), polystyrene (PS) and styrene-acrylonitrile copolymer (SAN). 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 greater than 75% and 90%, respectively, for the blends with PS and SAN. The blends developed with PMMA showed 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 the presence of new absorption bands was not observed. Thermogravimetric (TG) characterization showed that the styrenic blends presented greater thermal stability than the acrylic blend. The mechanical characterization showed that the PS/MBS blend presented synergism in maximum strength, while the PMMA/MBS and SAN/MBS blends were incompatible. The rheological results in the linear viscoelasticity region showed changes in the terminal region due to the addition of MBS, which presented a pseudo-solid behavior, due to the elastomeric domains for the immiscible and miscible blends. The morphological characterizations showed dispersed phase domains in the PMMA/MBS and SAN/MBS blends, highlighting the immiscibility of these polymer blends. The absence of dispersed phase domains confirmed the miscibility in the PS/MBS blend. The study of optical transparency correlated with miscibility and compatibility resulted in a greater understanding of these acrylic and styrenic blends with MBS.