Synthesis and morphology of model PS‐b‐PDMS copolymers

Abstract

True model linear poly(styrene‐b‐dimethylsiloxane) PS‐b‐PDMS copolymers were synthesized by using sequential addition of monomers and anionic polymerization (high‐vacuum techniques), employing the most recent experimental procedures that allow the controlled polymerization of each monomer to obtain blocks with controlled molar masses. The model diblock copolymers obtained were analyzed by using different techniques, such as size‐exclusion chromatography, 1H NMR, Fourier transform infrared spectroscopy, small angle X‐rays scattering (SAXS), and wide angle X‐rays scattering (WAXS). The PS‐b‐PDMS copolymers obtained showed narrow molar mass distribution and variable PDMS content, ranging from 2 up to 55 wt %. Compacted powder samples were investigated by SAXS to reveal their structure and morphology changes on thermal treatment in the interval from 30 to 200 °C. The sample with the highest PDMS content exhibits a lamellar morphology, whereas two other samples show hexagonally packed cylinders of PDMS in a PS matrix. For the lowest PDMS content samples, the SAXS pattern corresponds to a disordered morphology and did not show any changes on thermal treatment. Detailed information about the morphology of scattering domains was obtained by fitting the SAXS scattering curves. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3119–3127, 2010

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

“…PS‐ b ‐PDMS copolymers were synthesized by employing anionic polymerization and sequential addition of monomers, in a Schlenk‐type reactor (Figure ) by following the classical methodology reported in the literature . For such a purpose, two main objectives were imposed: (i) a proper purification of monomers and reagents; and (ii) the precise methodology for controlling D 3 polymerization .…”

“…These procedures provide solvents and monomers with a high‐purity level. For further details, the reader is encouraged to refer to the excellent reviews from Hadjichristidis et al ., Uhrig and Mays, and many papers regarding this subject that can be found in the scientific literature . Commercial n ‐buthyllithium solution ( n ‐Bu – Li + , 1.6 M in hexanes, Sigma Aldrich) was employed as anionic initiator.…”

“…Polymerizations were carried out in a specially designed Schlenk‐type reactor (Figure ), following the methodology reported in previous works . In this sense, the general procedure for the synthesis of PS‐ b ‐PDMS copolymers is briefly described as follows.…”

Facile Synthesis of Cx(AB)yCx Triblock Silicone Copolymers Utilizing Moisture Mediated Living‐End Chain Extension

“…Living ring‐opening polymerization employs a highly reactive initiator (typically BuLi) combined with a strained cyclic siloxane (most commonly hexamethylcyclotetrasiloxane (D 3 ), D = Me 2 SiO) at low temperatures, in solvents, and under an inert atmosphere; the use of difunctional initiators has also been reported . Blocks are formed by the sequential addition of different types of cyclic siloxanes that are added to the reactive chain end of the growing polymer . Chains are typically terminated with reactive silicone species such as chlorosilanes.…”

Synthesis and Characterization of Polydimethylsiloxane end-Modified Polystyrene from Poly(Styrene – co –Vinyltriethoxysilane) Copolymers

“…Block copolymers containing PDMS segments may be synthesized by techniques such as anionic polymerization [7][8][9] , atom transfer radical polymerization 10,11 , and reversible addition-fragmentation chain transfer polymerization 12 .…”