Synthesis of polystyrene-b-poly(ethylene glycol) block copolymers by radical exchange reactions of terminal RAFT agents

Figures & data

Scheme 1 Synthesis of xanthate functional polystyrene (PS-Xant).

Figure 1 ¹H NMR spectra of (a) PS-Xanth, (b) Me-PEG and (c) Me-PEG-MI.

Scheme 2 Synthesis of poly(ethylene glycol) macroazoinitiator (Me-PEG-MI).

Scheme 3 Synthesis of PS-b-PEG by thermally induced radical exchange reaction.

Figure 2 ¹H NMR spectra of PS-b-PEG.

Figure 3 FT-IR spectra of Me-PEG-MI, PS-Br and PS-b-PEG.

Figure 4 GPC traces of PEG, PS-Br, and PS-b-PEG.

Table 1. Molecular weight characteristics of the polymers at various stages.

Polymer	Mn,NMR^a (g mol^−1)	Mn,GPC^b (g mol^−1)	Mw/Mn^b
PEG	2010	3110	1.05
Me-PEG-MI	4300	4100	1.16
PS	1700	1660	1.23
PS-b-PEG	4090	4900	1.07

^aDetermined by ¹H NMR analysis.^bDetermined by GPC using PS standards.

Figure 5 DSC trace of PS, PEG, and PS-b-PEG.

Figure 6 FT-IR spectrum of the addition product of PS-Xant and AIBN.