Enhancement of mechanical and optical performance of commercial polystyrenes by blending with siloxane-based copolymers

NINAGO, MARIO DANIEL; HANAZUMI, VIVINA; PASSARETTI, MARÍA GABRIELA; VEGA, DANIEL ALBERTO; CIOLINO, ANDRÉS EDUARDO; VILLAR, MARCELO ARMANDO

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Año: 2017 vol. 134

0021-8995

Well-defined poly(styrene-block-dimethylsiloxane) copolymers (PS-b-PDMS) with low polydispersity index (Mw/Mn) and different compositions were synthesized by sequential anionic polymerization of styrene (S) and hexamethyl(ciclotrisiloxane) (D3) monomers. Synthesized PS-b-PDMS copolymers were characterized by 1H-nuclear magnetic resonance, size exclusion chromatography, Fourier transform infrared spectroscopy, and transmission electron microscopy. The physicochemical characterization determined that block copolymers have molar mass values close to ∼135,000 g mol−1, narrow Mw/Mn < 1.3, and chemical composition ranging from low to intermediate PDMS content. Blends of these copolymers with a commercial polystyrene (PS) were obtained by melt mixing and subsequently injection. Films obtained were flexible, and showed lower transparency than the original PS matrix. On the other hand, a 10 wt % incorporation of PS-b-PDMS copolymers leads to better mechanical performance by enhancing elongation at break (∼8.8 times higher) and opacity values (∼18 times higher). In addition, UV?Vis barrier capacity of the resulting blends is also increased (up to 400% higher). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45122.