TY - JOUR

T1 - Poly(2-cyclopropyl-2-oxazoline): From rate acceleration by cyclopropyl to thermoresponsive properties

AU - Bloksma, Meta M.

AU - Weber, Christine

AU - Perevyazko, Igor Y.

AU - Kuse, Anette

AU - Baumgärtel, Anja

AU - Vollrath, Antje

AU - Hoogenboom, Richard

AU - Schubert, Ulrich S.

PY - 2011/6/14

Y1 - 2011/6/14

N2 - The synthesis and microwave-assisted living cationic ring-opening polymerization of 2-cyclopropyl-2-oxazoline is reported revealing the fastest polymerization for an aliphatic substituted 2-oxazoline to date, which is ascribed to the electron withdrawing effect of the cyclopropyl group. The poly(2-cyclopropyl-2-oxazoline) (pCPropOx) represents an alternative thermo-responsive poly(2-oxazoline) with a reversible critical temperature close to body temperature. The cloud point (CP) of the obtained pCPropOx in aqueous solution was evaluated in detail by turbidimetry, dynamic light scattering (DLS) and viscosity measurements. pCPropOx is amorphous with a significantly higher glass transition temperature (Tg ∼ 80 °C) compared to the amorphous poly(2-n-propyl-2-oxazoline) (pnPropOx) (Tg ∼ 40 °C), while poly(2-isopropyl-2-oxazoline) piPropOx is semicrystalline. In addition, a pCPropOx comb polymer was prepared by methacrylic acid end-capping of the living cationic species followed by RAFT polymerization of the macromonomer. The polymer architecture does not influence the concentration dependence of the CP, however, both the CP and Tg of the comb polymer are lower due to the increased number of hydrophobic end groups. © 2011 American Chemical Society.

AB - The synthesis and microwave-assisted living cationic ring-opening polymerization of 2-cyclopropyl-2-oxazoline is reported revealing the fastest polymerization for an aliphatic substituted 2-oxazoline to date, which is ascribed to the electron withdrawing effect of the cyclopropyl group. The poly(2-cyclopropyl-2-oxazoline) (pCPropOx) represents an alternative thermo-responsive poly(2-oxazoline) with a reversible critical temperature close to body temperature. The cloud point (CP) of the obtained pCPropOx in aqueous solution was evaluated in detail by turbidimetry, dynamic light scattering (DLS) and viscosity measurements. pCPropOx is amorphous with a significantly higher glass transition temperature (Tg ∼ 80 °C) compared to the amorphous poly(2-n-propyl-2-oxazoline) (pnPropOx) (Tg ∼ 40 °C), while poly(2-isopropyl-2-oxazoline) piPropOx is semicrystalline. In addition, a pCPropOx comb polymer was prepared by methacrylic acid end-capping of the living cationic species followed by RAFT polymerization of the macromonomer. The polymer architecture does not influence the concentration dependence of the CP, however, both the CP and Tg of the comb polymer are lower due to the increased number of hydrophobic end groups. © 2011 American Chemical Society.

UR - http://www.scopus.com/inward/record.url?scp=79958789904&partnerID=8YFLogxK

U2 - 10.1021/ma200514n

DO - 10.1021/ma200514n

M3 - Article

AN - SCOPUS:79958789904

VL - 44

SP - 4057

EP - 4064

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 11

ER -