One‐pot orthogonal thiol‐ene click polymerization and ring‐opening grafting reaction of CO<sub>2</sub>‐based disubstituted δ‐valerolactone
Jiawen Song, Kaihao Chen, Yuanhao Feng, Xufeng Ni, Jun Ling
Abstract
Abstract Being a disubstituted δ‐valerolactone synthesized by the telomerization of carbon dioxide with 1,3‐butadiene, 3‐ethylidene‐6‐vinyltetrahydro‐2H‐pyran‐2‐one (EVL) contains a six‐membered ring and two unsaturated groups. This report describes the synthesis of an amphiphilic graft copolymer by the combination of thiol‐ene click polymerization and ring‐opening grafting reaction of EVL, ethyldithiol (EDT), and methoxy polyethylene glycol (mPEG‐OH). The alternating copolymer of P(EVL‐ alt ‐EDT) with 17.9 wt% CO 2 content and weight‐average molecular weight ( M w ) of 7 kg/mol was prepared by means of the free radical thiol‐ene click polymerization of EVL with EDT initiated by 2,2‐dimethoxy‐1,2‐diphenylethanone under UV irradiation. The following alcoholysis of the lactone ring of P(EVL‐ alt ‐EDT) backbone by mPEG‐OH is catalyzed by 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene, producing the amphiphilic graft copolymer P(EVL‐ alt ‐EDT)‐ g ‐PEG 750 with M w of 12 kg/mol. The polymers are characterized by nuclear magnetic resonance, Fourier transform infrared, matrix‐assisted laser desorption ionization‐time of flight mass spectra, size exclusion chromatography and differential scanning calorimetry. The one‐pot orthogonal strategy is a new utilization of EVL in synthetic polymers and it is significant to the carbon dioxide transformation.