Styragel column

NMR spectroscopy. ¹H NMR spectra of all endfunctional PIBs were recorded on a Varian 500 MHz spectrometer. All measurements were performed in CDCl₃ as solvent and at 30 °C. For spectra calibration of the ¹H NMR spectra, the chloroform peak was set to 7.26 ppm.
Gelpermeation chromatography (GPC). The GPC equipment was composed of a Waters 515 HPLC pump, Waters Styragel column set with three columns (HR1, HR2, HR4), and it was equipped with an Aligent 390 RI detector. THF was used as mobile phase with a flow rate of 1 mL/min. The average molar masses and the polydispersity (M_w/M_n), were determined by the use of a calibration made with narrow MWD polystyrene standards in the molecular weight range of 104 to 6 × 10⁵ Da.

Gel Permeation Chromatography (GPC) was utilized in order to determine the molecular weights of PGBSu, PEBSu, PXBSu, and PSBSu. Tests were conducted using Styragel column (Waters, Milford, CT, USA), with tetrahydrofuran (THF) as solvent in which samples (1 mg/mL) were dissolved.

¹H, ¹³C and ¹⁹F NMR spectra of intermediates were recorded on a JEOL resonance ECZ 400S spectrometer (400 MHz) in CDCl₃. Tetramethylsilane (TMS) and CDCl₃ were used as internal standards for ¹H and ¹³C NMR, respectively; CF₃CO₂H was used as an external standard for ¹⁹F NMR. FT-IR spectra were recorded on a Nicolet AVATAR-360 FT-IR spectrophotometer with a resolution of 4 cm⁻¹. Number-average molecular weights (M_n) and molecular weight distributions (M_w/M_n) were obtained on a conventional gel permeation chromatography (GPC) system equipped with a Waters 515 Isocratic HPLC pump, a Waters 2414 refractive index detector, and a set of Waters Styragel columns (HR3 (500–30 000), HR4 (5000–600 000) and HR5 (50 000–4 000 000), 7.8 × 300 mm, particle size: 5 μm). GPC measurement was carried out at 35 °C using tetrahydrofuran (THF) as eluent with a flow rate of 1.0 mL min⁻¹. The system was calibrated with linear polystyrene standards. Differential scanning calorimetry (DSC) was performed on a TA Q200 DSC instrument in N₂ with a heating rate of 10 °C min⁻¹. Thermogravimetry analysis (TGA) was conducted on a TA Discovery TGA 55 thermal analysis system in N₂ with a heating rate of 10 °C min⁻¹. UV/vis spectra were acquired on a Hitachi U-2910 spectrophotometer.

Weight average molecular weight (M_w), number average molecular weight (M_n), and polydispersity index (PI) of PLA-c and the fraction of PLA present in PLA-g-TPCS, PLA-GRH, and PLA-g-TPCS-GRH were determined by the method described in previous work [17 (link),21 (link)] using a Waters gel permeation chromatograph (Waters Corp., Milford, MA, USA) equipped with a 1515 isocratic HPLC pump, a 717plus autosampler, four Styragel^® columns (HR1, HR2, HR3, and HR4), and a 2414 refractive index detector interface (Waters Corp.). Experiments were conducted in triplicate.