Styrene–butadiene block copolymer with high cis‐1,4 microstructure

Abstract

ABSTRACT:The sequential block copolymerization of styrene (St) and butadiene (Bd) was carried out with an activated rare earth catalyst composed of catalyst neodymium tricarboxylate (Nd), cocatalyst Al(i-Bu) 3 (Al), and chlorinating agent (Cl). The microstructure, composition, and morphology of the copolymer were characterized by FTIR, 1 H NMR, 13 C NMR, and TEM. The results show that styrenebutadiene diblock copolymer with high cis-1,4 microstructure of butadiene units ( 97 mol %) was synthesized. The cis-selectivity for Bd units was almost independent on the content of styrene units in the copolymer ranging from 18.1 mol % to 29.8 mol %. The phase-separated morphology of polystyrene (PS) domains of about 40 nm tethered by the elastomeric polybutadiene (PB) segments is observed. The PS-b-cis-PB copolymer could be used as an effective compatilizer for noncompatilized binary PS/cis-PB blends.

Preparation of poly(styrene‐co‐butadiene) fine latex via a gemini surfactant‐induced low‐temperature initiation semibatch emulsion polymerization system

“…For example, the signals at 30.42 assignment to T 1 ‐S indicates the presence of the St‐ trans ‐1,4 BD sequence. No signals of St‐vinyl BD linkage in the vicinity of a chemical shift at 32.33 ppm are observed in the spectrum …”

“…The spectrum of the copolymer sample displays typical signals of BD and St units inserted within the SBR polymer chain. The chemical shifts and the assignments of the 13 C NMR signals of the different monomer units are listed in Table for the aliphatic region . Table shows the constitutional monomeric units of the SBR copolymer for identification using the 13 C NMR spectrum.…”

Synthesis and structure of 1,3-bis(hydroxysilyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane

“…It has been found that the existence of bulky substituents on the silicon atoms increases the thermal and hydrolytic stability of cyclodisilazanes. Therefore, phenylsubstituted cyclodisilazanes are expected to be introduced into the backbone of linear polysiloxane chains to synthesize thermally resistant elastomers [8,9]. An important goal in this area is the synthesis of cyclodisilazane monomer [10e16] with a feasible structure.…”

Neodymium‐Based Catalyst for the Coordination Polymerization of Butadiene: From Fundamental Research to Industrial Application

“…The first paper on the use of lanthanides for conjugated dienes polymerization originated in 1964 . There are many publications on the neodymium‐based catalysts for synthesis of Nd–BR in laboratory or in industry . The large‐scale industrial production of BR by neodymium‐based catalyst was established in the early to mid 1980s, first by Anic/Eni and shortly after by Bayer .…”