Synthesis and Characterization of Syndiotactic Polystyrene-Polyethylene Block Copolymer.

Lamparelli Lamparelli,Buonerba Buonerba,Camurati Camurati,Speranza Speranza,Oliva Oliva

doi:10.3390/polym11040698

Lamparelli Lamparelli, Buonerba Buonerba + Show 3 more

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https://doi.org/10.3390/polym11040698

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Abstract

The direct synthesis of syndiotactic polystyrene-block-polyethylene copolymer (sPS-b-PE) with a diblock structure has been achieved. The synthetic strategy consists of the sequential stereocontrolled polymerization of styrene and ethylene in the presence of a single catalytic system: cyclopentadienyltitanium(IV) trichloride activated by modified methylaluminoxane (CpTiCl3/MMAO). The reaction conditions suitable for affording the partially living polymerization of these monomers were identified, and the resulting copolymer, purified from contaminant homopolymers, was fully characterized. Gel permeation chromatography coupled with two-dimensional NMR spectroscopy COSY, HSQC, and DOSY confirmed the block nature of the obtained polymer, whose thermal behaviour and thin film morphology were also investigated by differential scanning calorimetry, powder wide angle x-ray diffraction, and atomic force microscopy.

Highlights

Syndiotactic polystyrene is one of the most significant achievements of homogeneous polyinsertion catalysis [1,2]
Some of us succeeded in the synthesis of an ethylene-styrene block copolymer with a isotactic styrene sequence joined to an ethylene-alt-styrene isotactic sequence [24]
The gas was vented off, the solution was poured into acidified methanol, and the polymer was collected by filtration and drying in vacuo (Yield: 950 mg)

Summary

Introduction

Syndiotactic polystyrene (sPS) is one of the most significant achievements of homogeneous polyinsertion catalysis [1,2]. Besides its employment as engineering plastic [3] thanks to a high melting temperature combined with favourable crystallization kinetics, sPS appears as a smart polymer due to its nanoporous crystalline structure [4,5,6] In this respect, many studies have been performed to disclose its ability to selectively clathrate small molecules in order either to remove the undesirable ones from the environment or to release the useful ones into a particular context [7,8]. Some of us succeeded in the synthesis of an ethylene-styrene block copolymer with a isotactic styrene sequence joined to an ethylene-alt-styrene isotactic sequence [24] The key to this achievement is living polyinsertion, which can be obtained even with traditional catalysts by working at a low temperature.

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