Supporting Information for

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1 Supporting Information for ʺNon-Strainedʺ γ-butyrolactone-based Copolyesters: Copolymerization Characteristics and Composition-Dependent (Thermal, Eutectic, Cocrystallization and Degradation) Properties Miao Hong, * Xiaoyan Tang, Brian S. Newell, and Eugene Y.-X. Chen * * Correspondence to: miaohong@sioc.ac.cn; eugene.chen@colostate.edu Experimental Details Materials, Reagents, and Methods. All synthesis and manipulations of air- and moisture-sensitive materials were carried out in flamed Schlenk-type glassware on a dual-manifold Schlenk line, on a high-vacuum line, or in an argon-filled glovebox. HPLC-grade organic solvents were first sparged extensively with nitrogen during filling 20 L solvent reservoirs and then dried by passage through activated alumina (for dichloromethane, DCM) followed by passage through Q-5 supported copper catalyst (for toluene, TOL) stainless steel columns. Tetrahydrofuran (THF) was degassed and dried over Na/K for 3 days, followed by distillation. γ-butyrolactone (γ-bl) was purchased from Acros Organics Co, which was dried over CaH 2 for 3 days, vacuum distillated and stored in the glovebox for further use. ε-caprolactone (ε-cl) and δ-valerolactone (δ-vl) were purchased from Aldrich Chemical Co, dried over CaH 2 for 3 days, vacuum distillated and stored at 40 ºC in the glovebox for further use. Tri[N,N-bis(trimethylsilyl)amide]lanthanum {La[N(SiMe 3 ) 2 ] 3 } was purchased from Aldrich Chemical Co and used as received. 1-tert-Butyl-4,4,4-tris(dimethylamino)-2,2-bis- [tris(dimethylamino)phosphoranylid enamino]-2λ 5,4λ 5 -catenadi(phosphazene) ( t Bu-P 4, ~0.8 M in hexane) was purchased from Aldrich Chemical Co and the solvent was removed in vacuo prior to use. Benzyl alcohol (BnOH) was purchased from Alfa Aesar Chemical Co and Aldrich Chemical Co, respectively, and purified by distillation over CaH 2. 2,2-Diphenylethanol (Ph 2 CHCH 2 OH) was purchased from Aldrich Chemical Co and purified by dissolving in toluene over CaH 2, filtering after stirring overnight, and removing the solvent. General Polymerization Procedures. Polymerizations were performed either in 20 ml glass reactors inside the inert glovebox for room temperature (RT) runs or 25 ml flame-dried Schlenk flasks interfaced to the dual-manifold Schlenk line for runs using an external temperature bath. The reactor was S1

2 charged with a predetermined amount of monomers and solvent. For runs at RT, the polymerization was initiated by rapid addition of a predetermined amount of catalyst (with or without initiator) in the solvent via a gastight syringe. For runs using an external temperature bath, the reactor was sealed, taken out of glovebox, and then immersed in the external temperature bath under the predetermined temperature. After equilibration at the desired polymerization temperature, the polymerization was initiated by rapid addition of a predetermined amount of catalyst (with or without initiator) in the solvent via a gastight syringe. After a desired period of time, the polymerization was quenched by addition of 5 ml of benzoic acid/chcl 3 (10 mg/ml). After the gelled polymer was dissolved in CHCl 3, a 0.2 ml of aliquot was taken from the reaction mixture and prepared for 1 H NMR analysis to obtain the percent monomer conversion data. The quenched mixture was then precipitated into 100 ml of cold methanol, filtered, washed with methanol to remove the unreacted monomer, and dried in a vacuum oven at RT to a constant weight. In the case of polymer products with a T m below RT, the quenched mixture was then decanted into a vessel containing 100 ml of cold methanol. After all of the viscous polymer precipitated at the bottom of the vessel, the supernatant liquid was decanted off. The remaining polymer was redissolved and reprecipitated to remove all of the unreacted monomer, and then dried in a vacuum oven at RT to a constant weight. Polymer Characterizations. Copolymer compositions and microstructures were determined by 1 H NMR and 13 C NMR spectra recorded on a Varian Inova 400 MHz spectrometer. Chemical shifts for 1 H and 13 C spectra were referenced to internal solvent resonances and were reported as parts per million relative to SiMe 4. Polymer number-average molecular weights (M n ) and dispersity (Ɖ = M w /M n ) values were measured by gel permeation chromatography (GPC) analyses carried out at 40 ºC and a flow rate of 1.0 ml/min, with DMF as the eluent on a Waters University 1500 GPC instrument equipped with one PLgel 5 µm guard and two PLgel 5 µm Mixed-C columns (Polymer Laboratories; linear range of MW = 200 2,000,000). The instrument was calibrated with 10 PMMA standards, and chromatograms were processed with Waters Empower software (version 2002). Melting-transition temperatures (T m ) and glass-transition temperatures (T g ) were measured by differential scanning calorimetry (DSC) on a Q20 DSC, TA Instrument. All T m and T g values were obtained from the second scan after the thermal history S2

3 was removed from the first scan. The first heating rate was 20 C/min, while the cooling rate was 5 C/min and the second heating rate was 10 C/min. Maximum rate decomposition temperatures (T max ) and decomposition onset temperatures (T d, defined at 5% weight loss) of the polymers were measured by thermal gravimetric analysis (TGA) on a Q50 TGA Thermogravimetric Analyzer, TA Instrument. Polymer samples were heated from ambient temperatures to 700 C at a rate of 20 C/min. X-ray diffraction measurements (XRD) were performed on a Bruker D-8 Discover DaVinci X-ray diffractometer (Cu-Ka X-ray source, line focus) with soller slits on the primary and diffracted beam side (2.5 separation), and the instrument alignment was checked using the NIST 1976b SRM. A 0.6 mm divergent slit was placed on the primary beam side and a high-resolution energy-dispersive LYNXEYE-XE-T detector on the diffracted beam side during the XRD studies. The samples were annealed by heating to 80 C with a rate of 10 C/min and then cooling to RT; the annealed samples were stored in a 20 C refrigerator and removed from the refrigerator for immediate XRD analysis. Small-angle X-ray scattering (SAXS) data were collected on a Rigaku S-Max 3000 High Brilliance three-pinhole SAXS system outfitted with a MicroMax-007HFM rotating anode (CuKα), Confocal Max-Flux Optic, Gabriel multiwire area detector, and a Linkam thermal stage. Dry polymer samples were sandwiched between Kapton windows (0.05 mm thick 10 mm diameter). The samples were annealed by heating from RT to 80 C with a rate of 10 C/min and then cooling to 10 C with a rate of 5 C/min. The data were collected at 10 C with an exposure time of 3600 s. Hydrolytic Degradation Tests of Polymers. Square-shaped polymer samples for degradation tests with dimensions of 4 mm 4 mm 1 mm were cut from polymer films (30 mm 10 mm 1 mm) prepared by compression molding at ºC for 5 min. For the samples with a melting-transition temperature below RT, the polymer films were removed from the molder after solidifying at 20 ºC for 10 min in the freezer and cut as quickly as possible. The weighted three specimens of each polymer type were separately immersed in 4 ml of neutral, acidic, and basic aqueous solutions. After a predetermined degradation time, the supernatant liquid was decanted off and the remaining specimen was washed thoroughly with distilled water and methanol, and then dried under vacuum at RT for 2 days to a constant weight. After the thoroughly dried specimen was weighed, it was reimmersed in the above aqueous S3

4 solutions again, and such a process was repeated at each time point. Table S1. Monomer conversion and γ-bl incorporation as a function of polymerization time Copolymer Run Time (min) Conv. (BL%) e Conv. (M%) e Incorp. (BL mol%) e PBL-co-PCL a PBL-co-PCL b PBL-co-PVL c PBL-co-PVL d a Conditions: La[N(SiMe 3 ) 2 ] 3 (La) = 6.3 umol, Ph 2 CHCH 2 OH = 12.6 umol, (ε-cl+γ-bl)/la/ph 2 CHCH 2 OH = 4000/1/2, ε-cl/γ-bl = 1/3, [ε-cl+γ-bl] = 5 M in THF, Temp. = 25 C. b Conditions: La[N(SiMe 3 ) 2 ] 3 (La) = 10.0 umol, Ph 2 CHCH 2 OH = 20.0 umol, (ε-cl+γ-bl)/la/ph 2 CHCH 2 OH = 1000/1/2, ε-cl/γ-bl = 1/15, [ε-cl+γ-bl] = 6.67 M in THF, Temp. = 40 C. c Conditions: t Bu-P 4 = 50 umol, Ph 2 CHCH 2 OH = 50 umol, (δ-vl+γ-bl)/ t Bu-P 4 /Ph 2 CHCH 2 OH = 100/1/1, δ-vl/γ-bl = 1/3, [δ-vl+γ-bl] = 6.67 M in THF, Temp. = 25 C. d Conditions: t Bu-P 4 = 50 umol, Ph 2 CHCH 2 OH = 50 umol, (δ-vl+γ-bl)/ t Bu-P 4 /Ph 2 CHCH 2 OH = 100/1/1, δ-vl/γ-bl = 1/10, [δ-vl+γ-bl] = 6.67 M in THF, Temp. = 40 C. e Monomer conversions and γ-bl incorporations of the copolymers measured by 1 H NMR spectra. S4

5 Figure S1. Overlay of 1 H NMR spectra (CDCl 3 ) of PBL-co-PCL copolymers quenched at different polymerization times (Table S1, Runs 1 6) BL Incorp. (mol%) CL Conv. (mol%) BL Conv. (mol%) Results Polymerization Time (min) 15 Figure S2. Dependence of monomer conversion and γ-bl incorporation on polymerization time in the copolymerization of γ-bl with ε-cl at 25 C (Table S1, Runs 1 6). S5

6 Figure S3. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PCL (γ-bl mol% = 17.5%, Table 1, run 4). Figure S4. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PCL (γ-bl mol% = 33.6%, Table 1, run 13). S6

7 Figure S5. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PCL (γ-bl mol% = 55.2%, Table 1, run 14). Figure S6. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PCL (γ-bl mol% = 76.0%, Table 1, run 17). S7

8 Figure S7. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PVL (γ-bl mol% = 8.0%, Table 2, run 2). Figure S8. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PVL (γ-bl mol% = 23.7%, Table 2, run 9). S8

9 Figure S9. 13 C NMR spectrum (CDCl 3 ) of PBL-co-PVL (γ-bl mol% = 54.0%, Table 2, run 11). Figure S C NMR spectrum (CDCl 3 ) of PBL-co-PVL (γ-bl mol% = 71.2%, Table 2, run 13). S9

10 Table S2. Copolymerization Data for the Statistical PBL-co-PCL and PBL-co-PVL copolymers a a Copolymer PBL-co-PCL PBL-co-PVL X b (M/BL) Incorp. c (mol%) Y (M/BL) d F e G e 2.0 (1/0.5) (1/1) (1/3) (1/8) (1/0.5) (1/1) (1/3) (1/5) (1/8) Conditions for copolymerizations of γ-bl with ε-cl: La[N(SiMe 3 ) 2 ] 3 (La) = 6.3 umol, Ph 2 CHCH 2 OH = 12.6 umol, (ε-cl+γ-bl)/la/ph 2 CHCH 2 OH = 4000/1/2, [ε-cl+γ-bl] = 5 M in THF, Temp. = 40 C; Conditions for copolymerizations of γ-bl with δ-vl: t Bu-P 4 = 12.6 umol, Ph 2 CHCH 2 OH = 12.6 umol, (δ-vl+γ-bl)/p 4 - t Bu/Ph 2 CHCH 2 OH = 400/1/1, [δ-vl+γ-bl] = 5 M in THF, Temp. = 40 C. b X = M M /M B, M M and M B are the monomer molar composition in feed. c γ-bl incorporations of the copolymers measured by 1 H NMR spectra. d Y = dm M /dm B, dm M and dm B are the copolymer molar compositions. e According to the Finemann-Ross method, the monomer reactivity ratios can be obtained from the equation: G = Fr E -r D where the reactivity ratios, r E and r D, corresponding to the ethylene and comonomer, respectively. The parameters G and F are defined as: G = X(Y-1)/Y and F = X 2 /Y (Fineman, M.; Ross, S. D. J. Polym. Sci. 1950, 5, ). S10

11 G 0.6 G = 1.41F (R 2 =0.99) F G 0.3 G = 0.86F-0.16 (R 2 =0.99) F Figure S11. Finemann-Ross plots (top) PBL-co-PCL produced by La[N(SiMe 3 ) 2 ] 3 /Ph 2 CHCH 2 OH catalyst/initiator system; (bottom) PBL-co-PVL produced by P 4 - t Bu/Ph 2 CHCH 2 OH catalyst/initiator system. S11