Ring-Opening Polymerization of Lactones Catalyzed by Silicon-Based Lewis Acid

Table 3

Glass-transition temperatures of the polymers.

Run	Monomer	Catalyst	Mn^a (kg/Mol)	Đ^a	Tg^b (°C)
12	ε-CL	1a	8	1.7	−46.2
32		Sn(Oct)2^c	30	1.9	−60.8
21	δ-VL	1a	6	1.4	−34.7
33		Sn(Oct)2^c	9	1.4	−45.9
23	β-PL	1a	1.8	1.5	−33.9
34		Al(O^iPr)3	4.0	1.3	−20.5
29	TMC	1a	7	2.3	−10.5
35		TBD^c	17	2.0	−20.4

Conditions: bulk, [M]₀ : [cat.] = 100 : 1, temp. = 100°C.
^aDetermined by GPC analysis calibrated with standard polystyrenes in THF.
^bDetermined by DSC in the second heating scan.
^cInit. = BnOH, [M]₀ : [Init.] : [cat.] = 100 : 1 : 0.25, [M]₀ = 2.0 mol/L.