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

MARIO D. NINAGO; VIVINA HANAZUMI; GABRIELA M. PASSARETTI; DANIEL A. VEGA; ANDRÉS E. CIOLINO; MARCELO A. VILLAR

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2017

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 copolymerswere characterized by 1H-Nuclear Magnetic Resonance (1H-NMR), Size Exclusion Chromatography (SEC), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission electron microscopy (TEM).The physicochemical characterization determined that block copolymers have molar mass values close to ~135,000 gmol-1, narrow Mw/Mn < 1.3, and chemical composition ranging from low to intermediate PDMS content. Blends of these copolymers with a commercial poly(styrene) (PS) were obtained by melt mixing and subsequently injection. Films obtained were flexible, and showed lowertransparency 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).