Statistical Copolymers of n-Butyl Vinyl Ether and 2-Chloroethyl Vinyl Ether via Metallocene-Mediated Cationic Polymerization. A Scaffold for the Synthesis of Graft Copolymers

Stavros Zouganelis; Ioannis Choinopoulos; Ioannis Goulas; Marinos Pitsikalis

doi:10.3390/polym11091510

Statistical Copolymers of n-Butyl Vinyl Ether and 2-Chloroethyl Vinyl Ether via Metallocene-Mediated Cationic Polymerization. A Scaffold for the Synthesis of Graft Copolymers

Polymers (Basel). 2019 Sep 16;11(9):1510. doi: 10.3390/polym11091510.

Authors

Stavros Zouganelis¹, Ioannis Choinopoulos¹, Ioannis Goulas¹, Marinos Pitsikalis²

Affiliations

¹ Industrial Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece.
² Industrial Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece. pitsikalis@chem.uoa.gr.

Abstract

The cationic statistical copolymerization of n-butyl (be) and 2-chloroethyl vinyl ether (CEVE), is efficiently conducted using bis(η⁵-cyclopentadienyl)dimethyl zirconium (Cp₂ZrMe₂) in combination with tetrakis(pentafluorophenyl)borate dimethylanilinum salt [B(C₆F₅)₄]^-[Me₂NHPh]⁺, as an initiation system. The reactivity ratios are calculated using both linear graphical and non-linear methods. Structural parameters of the copolymers are obtained by calculating the dyad sequence fractions and the mean sequence length, which are derived using the monomer reactivity ratios. The glass transition temperatures (T_g) of the copolymers are measured by Differential Scanning Calorimetry (DSC), and the results are compared with predictions based on several theoretical models. The statistical copolymers are further employed as scaffolds for the synthesis of graft copolymers having poly(vinyl ether)s as a backbone and either poly(ε-caprolactone) (PCL) or poly(l-lactide) (PLLA) as side chains. Both the grafting "onto" and the grafting "from" methodologies are employed. The reaction sequence is monitored by Size Exclusion Chromatography (SEC), NMR and IR spectroscopies. The advantages and limitations of each approach are thoroughly examined.

Keywords: cationic polymerization; graft copolymers; metallocene complexes; poly(l-lactide); poly(ε-caprolactone); ring opening polymerization; statistical copolymers; vinyl ethers.