Two-arm PCL and PLLA macrophotoinitiators with benzoin end-functional groups by combination of ROP and click chemistry and their use in the synthesis of A2B2 type miktoarm star copolymers. (11th August 2017)

• Record Type: Journal Article
• Authors: Uyar, Zafer; Durgun, Mustafa; Yavuz, M. Sukru; Abaci, M. Bahattin; Arslan, Ulku; Degirmenci, Mustafa
• Is Part Of: Polymer. Volume 123(2017)
• Page Start: 153
• Page End: 168
• Publication Date: 2017-08-11
• Subjects: Poly(l-lactide) -- poly(ε−caprolactone) -- Macrophotoinitiator -- Ring opening polymerization (ROP) -- Click chemistry -- Photoinduced polymerization -- Miktoarm star copolymer; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2017.07.019
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Novel and well defined macrophotoinitiators with two-arm poly( ε −caprolactone) (PCL) and poly(l -lactide) (PLLA) chains bearing two benzoin photofunctionalities (BPI) at the connection point of the polymer chains have been synthesized by combination of ring opening polymerization (ROP) and click chemistry. Initially, dibromo end-functionalized two-arm PCL, (PCL)2 -(Br)2, and PLLA, (PLLA)2 -(Br)2, were synthesized by ROP of ε −caprolactone andl -lactide monomers in bulk, using 2, 2-bis(bromomethyl)-1, 3-propanediol as the initiator and stannous-2-ethylhexanoate, (Sn(Oct)2 ), as the catalyst. Then, the terminal bromines of the polymer arms were converted into azide groups with sodium azide (NaN3 ). Subsequently, well-defined two-arm PCL and PLLA macrophotoinitiators with benzoin end functional groups [(PCL)2 -(BPI)2 and (PLLA)2 -(BPI)2 ] were obtained from the click reaction between diazido end-functionalized (PCL)2 -(N3 )2 and (PLLA)2 -(N3 )2 polymers and an alkyne-terminated benzoin photoinitiator (BPI-alkyne) which was synthesized from benzoin and propargyl bromide. The 1 H NMR, FT-IR, GPC, UV, and fluorescence spectroscopic studies revealed that two-arm poly( ε −caprolactone) and poly(l -lactide) having benzoin photofunctional groups bound to the linking point of the chains were obtained. These polymers were then used as macrophotoinitiators for the photoinduced free radical promoted cationic polymerization of cyclohexene oxide (CHO) monomer to synthesize A2 B2 type miktoarm star copolymers comprised of PCL or PLLA as A blocks and PCHO as B blocks. Graphical abstract: Highlights: Combination of ROP and click chemistry for the synthesis of macrophotoinitiators. Preparation of well-defined two-arm PCL and PLLA macrophotoinitiators with benzoin end groups. Synthesis of A2 B2 type miktoarm star copolymers by the photoinduced cationic polymerization.