Tin 2 bis 2 ethylhexanoate sn oct 2

The L,L-lactide and rac-lactide (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) were purified by recrystallization from hexane/toluene. Tin (II) bis(2-ethylhexanoate) (Sn(Oct)₂, Sigma-Aldrich, Tokyo, Japan), chloroform, and methanol (Kanto Chemical Co. Inc., Tokyo, Japan) were used as received. The NMR solvent (CDCl₃) was obtained from Fujifilm Wako Pure Chemical Corporation, Osaka, Japan.

L-lactide (L-LA) and D-Lactide (D-LA) were purchased from Corbion (Amsterdam, The Netherlands). Tin(II)bis(2-ethylhexanoate) (Sn(Oct)₂) (Sigma Chemical Co., St. Louis, MO, USA, purity ≥ 99%) and 1-dodecanol (DoOH) (Sigma-Aldrich, St. Louis, MO, USA, purity ≥ 99.5%) were purified by distillation under reduced pressure and dissolved in dry toluene. The toluene was dried by refluxing over a benzophenone-Na complex and distilled in a nitrogen atmosphere just prior to use. High molecular weight PLLA (M_n = 181,493 g/mol, M_w = 425,561 g/mol, PDI = 2.345) was synthesized by ring-opening polymerization of L-lactide (Corbion, Amsterdam, The Netherlands) at 130 °C for 24 h. Other PLA homopolymers for nucleating agent materials: PDLA (M_n = ~87,000 g/mol, M_w = ~125,000 g/mol, PDI = 1.437) and PLLA (M_n = ~87,000 g/mol, M_w = 153,000 g/mol, PDI = 1.759) were also synthesized by a similar method. Dichloromethane (JT Baker, HPLC grade) and CO₂ (Purity ≥ 99.9%) were used as received.