Grafting of Poly(2‐Oxazoline) Side Chains from Polyester Containing Oxazoline Units and Their Blends with Water Soluble Vinyl Polymers. Issue 1 (14th December 2020) - Fukaya, Koki
Abstract: Ternary polycondensation of thiomalic acid (TMA), adipic acid (ADA), and 1, 5‐pentanediol (PD) at 80 °C proceeds to give polyester having pendent mercapto groups. After the mercapto groups are consumed quantitatively by a Michael addition with 2‐isopropenyl‐2‐oxazoline (IPOx) to create an initiation point for grafting, successive additions of methyl triflate (MeOTf) and 2‐oxazoline allow ring‐opening polymerization of 2‐oxazoline from the IPOx unit to give a graft copolymer with a M n of 2.2 × 10 4 ‐ 3.7 × 10 4 and an molecular dispersity index ( M w / M n = 1.9–2.6). The synthesized polyester‐based graft copolymer is water‐soluble and forms transparent blend films with poly(vinyl alcohol) (PVA) and poly( N ‐isopropy acrylamide) (PNIPAM) using solvent cast methods. Differential scanning calorimetry measurements show that blends with PVA (<30% of the graft copolymer) show a single T g s over the whole composition range. All scans for the blends with PNIPAM have a single T g s that is between those of the parent polymers indicating that the graft copolymer shows excellent miscibility with PNIPAM, although the parent polyester, poly(TMA‐ alt ‐PD)‐ co ‐poly (ADA‐ alt ‐PD) does not exhibit such miscibility. Abstract : Ternary polycondensation of thiomalic acid, adipic acid, and 1, 5‐pentanediol proceeds to give polyester having pendent mercapto groups. Michael addition of mercapto groups and 2‐isopropenyl‐2‐oxazoline to create an initiation point for ring‐opening grafting to give expected graft copolymers. The synthesized polyester‐based graft copolymer is water‐soluble and forms miscible blends with poly(vinyl alcohol) and poly( N ‐isopropy acrylamide).