Metal-free ring-opening block copolymerization of epoxide initiated with organic ammonium acetate salt Lisa Nakajima, Yuiko Kikuchi, Hisatoyo Morinaga * Department of Materials and Science Kochi National College of Technology

Metal-free polymerization Conventional polymerization using metallic initiators and catalysts Metal-free polymerization Polymers with residue of toxic metals Polymers without possible contamination of toxic metals Limitation for usage  Biomedical engineering  Environmental engineering

Controlled polymerization Non-controlled polymerization Controlled polymerization 1. Polymer chain length can be controlled. 2. Propagating species is stable. ⊖ ⊖ ⊖ ⊖ ⊖ ⊖ 1. Polymer chain length cannot be controlled. 2. Propagating species is unstable.

Metal-free controlled polymerization of glycidyl phenyl ether (GPE) 1) Morinaga, H. et al, Macromolecules, 2007, 40, ) Morinaga, H. et al., Journal of Network polymer, Japan, 2010, 31(6), ) Morinaga, H. et al., Journal of Polymer Science, Part A : Polymer Chemistry, 2011, 49(24),

Sequential block copolymerization by controlled polymerization 1 st monomer Controlled polymerization block copolymerization poly(1 st monomer) having stable propagating species AB diblock copolymer ⊖ 2 nd monomer

Aliphatic polyester (Biodegradable polymer) Lactones

PURPOSE block copolymerization ？ block copolymer? Synthesis of metal-free and halogen-free AB diblock copolymer by sequential ring-opening polymerization of GPE and Lactone initiated with n-Bu 4 NOAc GPE n-Bu 4 NOAc Metal-free ring-opening polymerization ⊖ Lactone polyGPE poly(lactone) polyGPE n-Bu 4 NOAc: tetra-n-butylammonium acetate

Block copolymerization of GPE with β-PL initiated with n-Bu 4 NOAc [GPE] 0 :[  -PL] 0 =76:24 Yield = 92 % (water-insoluble part)  -PL:  -propiolactone

1 H NMR spectrum of poly(GPE)-block-poly(β-PL) [GPE] 0 :[  -PL] 0 =76:24 Ar 1 2 3, PPM

FT-IR spectrum of poly(GPE)-block-poly(β-PL) 1735 cm -1

Gel permeation chromatography (GPC) traces of poly(GPE)-block-poly(β-PL) from poly(GPE) M n : Number-averaged molecular weight M w /M n : Molecular weight distribution

Plausible mechanism for block copolymerization

CONCLUSION The metal-free and halogen-free block copolymer was successfully obtained by the sequential ring-opening polymerization of GPE and β-PL initiated with n-Bu 4 OAc.