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

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 (Tg) 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.

Comparative Study of Thermal Stability and Thermal Degradation Kinetics of Poly(Vinyl Ethers) with Different Side Groups

“…The OFW approach is based on the Doyle approximation. [41] Upon substitution of eq (6) to eq (4) the OFW equation can be obtained [42]- [44]:…”

“…Generally, neutral metallocene complexes of Group 4 with a suitable fluorinated aryl borate systems have been efficiently employed for the catalytic polymerization of a wide variety of monomers. [6][18]- [28] Although, the cationic polymerization of PEVE was successful, the direct cationic homopolymerization of AEVE is not possible due to the presence of the amine groups that can cause chain transfer, terminations and other side reactions. Thus, PAEVE was obtained by hydrazinolysis of PPEVE, following a synthetic path commonly used in the literature for its preparation.…”

Recent advances in applications of vinyl ether monomers for precise synthesis of custom-tailored polymers

“…Conventional cationic copolymerization promoted a competing process of ring-opening polymerization and rearrangement, whereas photo-driven cationic polymerization protocol with a RAFT agent facilitated chain propagation against the rearrangement. [B(C 6 F 5 ) 4 ]catalyzed statistical cationic copolymerization of BVE and CEVE [206]. Regardless of different monomers ratios used for polymerization, the reaction yielded polymers with similar characteristics (M n 10,000-14,000 g•mol 1 , PDI 1.5) (Scheme 38).…”

Thermal Stability and Kinetics of Thermal Decomposition of Statistical Copolymers of N-Vinylpyrrolidone and Alkyl Methacrylates Synthesized via RAFT Polymerization

“…e copolymer composition, the distribution, and the mean sequence length of the monomer units along the copolymeric chain are key parameters to elucidate the properties of the final product. An enormous amount of work, both experimental and theoretical, confirms the significance of statistical copolymerization in polymer science [20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”