Synthesis and characterization of model diblock copolymers of poly(dimethylsiloxane) with poly(1,4‐butadiene) or poly(ethylene)

Abstract

Model diblock copolymers of poly(1,4‐butadiene) (PB) and poly(dimethylsiloxane) (PDMS), PB‐b‐PDMS, were synthesized by the sequential anionic polymerization (high vacuum techniques) of butadiene and hexamethylciclotrisiloxane (D3) in the presence of sec‐BuLi. By homogeneous hydrogenation of PB‐b‐PDMS, the corresponding poly(ethylene) and poly(dimethylsiloxane) block copolymers, PE‐b‐PDMS, were obtained. The synthesized block copolymers were characterized by nuclear magnetic resonance (1H and 13C NMR), size‐exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and rheology. SEC combined with 1H NMR analysis indicates that the polydispersity index of the samples (Mw/Mn) is low, and that the chemical composition of the copolymers varies from low to medium PDMS content. According to DSC and TGA experiments, the thermal stability of these block copolymers depends on the PDMS content, whereas TEM analysis reveals ordered arrangements of the microphases. The morphologies observed vary from spherical and cylindrical to lamellar domains. This ordered state (even at high temperatures) was further confirmed by small‐amplitude oscillatory shear flow tests. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1579–1590, 2006

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

“…Glass transition temperature of PDMS ( T g 1 ∼ −125 °C) and PS ( T g 2 ∼ 102 °C) were determined (Table ). Obtained values are in accordance with those reported in the literature for these copolymers . PS‐ b ‐PDMS block copolymers are really stable since both blocks are stable.…”

Lipase Catalyzed Synthesis of Poly(ε-Caprolactone)−Poly(Dimethylsiloxane)−Poly(ε-Caprolactone) Triblock Copolymers

“…This property increased as the fraction of PDMS increased in the triblock copolymers, as can be seen in the TGA curves. For the PCL−PDMS−PCL triblock copolymers, the inflection observed in the TGA curves can be explained by assuming that a combination of free radicals results in the formation of thermally stable crosslinked products, which then decompose at higher temperatures [26,27]. Jana et al reported an increase in the thermal stability of the blends of low-density poly(ethylene) (LDPE) and PDMS (50/50 wt %) when dicumyl peroxide was used as a crosslinker [26].…”

“…Jana et al reported an increase in the thermal stability of the blends of low-density poly(ethylene) (LDPE) and PDMS (50/50 wt %) when dicumyl peroxide was used as a crosslinker [26]. This increase was explained as a consequence of the introduction of cross- links at the interface as well as the formation of inter-and intramolecular crosslinking in the bulk of the matrix [27].…”

Well-defined PE-b-PDMS diblock copolymers via the combination of thiol-ene click and esterification reactions: Facile synthesis and compatibilization for HDPE/silicone oil blends

“…The FT‐IR spectra (Fig. ) also certify the generation of block copolymers, in which new characteristic bands of siloxane structures appear at 1261 (symmetric −CH 3 deformation in Si−CH 3 bonds), 1094 and 1022 (asymmetric Si‐O‐Si stretching vibrations) and 802 cm −1 (Si−C stretching vibration) …”

“…In recent years, the synthesis of PE‐PDMS copolymers has been reported by different techniques in the literature. For example, PE‐ co ‐PDMS random copolymers by EtInd 2 ZrCl 2 /MAO catalyzed copolymerization of ethylene and PDMS macromonomer, PE‐ g ‐PDMS copolymers by catalytic hydrogenation of PB‐ g ‐PDMS, PE‐ b ‐PDMS diblock and PE‐ b ‐PDMS‐ b ‐PE triblock copolymers by sequential anionic polymerization of 1,3‐butadiene and hexamethylcyclotrisiloxane (D3) and subsequent hydrogenation have been achieved. In this study, the thiol‐ene click chemistry was introduced to yield carboxyl‐terminated polyethylene (PE‐COOH) from the reaction between vinyl‐terminated polyethylene (PE‐ene) and 3‐mercaptopropionic acid.…”