Table 1. Radical Ring-Opening Polymerization of 1 and 2 with DTBP^a.

entry	[M]	[M]0:[I]0b	[M]0 (mol L–1)	conv.c (%)	FE/FAe	Mn,SECf	ĐMf	Tgg (°C)	Td5% (°C)
1h	1	50:1	8.8	>99	23/77	3.1	2.17	78	206
2	1	100:1	1.9	>99	78/22	1.2	1.44	65	173
3	1	100:1	3.2	>99	65/35	4.7	2.11	68	210
4i	1	100:1	3.2	>99	78/22	2.4	1.92	65	205
5	1	100:1	4.7	>99	56/44	4.3	2.53	73	204
6i	1	100:1	4.7	>99	43/57	5.1	2.37	72	230
7	2	100:1	5	>99d	0/100	1.0	1.66	83	215
8	2	100:1	10	>99d	0/100	1.4	1.83	93	214

^aReactions were carried out over 20 h at 140 °C, under an Ar atmosphere, in anhydrous ODCB with [M]₀ = 1.9–10 mol L^–1 (M = 1 or 2), unless stated otherwise.

^bI = DTBP.

^cMonomer conversion to polymer, calculated by ¹H NMR spectroscopy by relative integration of the methylene signal of 1 (δ_H = 3.85 ppm, d, 2H) and the alkyl proton signal(s) of poly(1) (δ_H = 2.85–2.28 and/or 2.17–2.02, m, 2H).

^dMonomer conversion to polymer, calculated by ¹H NMR spectroscopy by relative integration of the methylene signal of 2 (δ_H = 3.85 ppm, s, 2H) and the alkyl proton signal of poly(2) (δ_H = 2.72–2.06, m, 2H).

^ePolymer composition between ester (F_E) and acetal (F_A) linkages, determined using ¹³C{¹H} NMR spectroscopy, based on the relative integration of signals corresponding to ester (δ_C = 170–172 ppm) and acetal linkages (δ_C = 113 ppm).

^fNumber-average molar mass and dispersity (M_n,SEC, Đ_M), calculated by SEC relative to polystyrene standards in a THF eluent, units in kg mol^–1.

^gValues obtained from DSC second heating cycle.

^hPolymerization was carried out in solvent-free over 20 h at 120 °C, under an argon atmosphere.

ⁱRepeat reactions, showing deviation in F_E/F_A.