1260 infinity multi detector gpc sec system

PBS scaffold was produced following the procedure previously published [16 (link)]. Briefly, a PBS (Poly(1,4-butylene succinate) extended with 1,6-diisocyanatohexane, Tm 120 °C, Aldrich, UK) solution (30 mL) in dichloromethane (15% w/v) was used to prepare each batch of the scaffold. The electrospinning process was carried out horizontally with 15 kV voltage (Spellman CZE 1000 R, Hauppauge, NY, USA) and a constant polymeric solution rate (0.8 mL/min) obtained through a programmable syringe pump (Aitecs PLUS SEP-21, Vilnius, Lithuania). The electrospun scaffold was collected on a stainless steel earthed rotating collector, positioned 15–20 cm away from the tip of the needle.
Molecular weight evaluation of PBS was carried out via size exclusion chromatography (SEC) by using an Agilent 1260 Infinity multi-detector GPC/SEC system. The elution was performed on a Phenogel 10⁴ column (Phenomenex, Torrance, CA, USA) using Hexafluoroisopropanol (Sigma-Aldrich, Gillingham, UK) as a mobile phase at 30 °C, with a flow rate of 0.6 mL/min. Standards of PEG were used for calibration. The average molecular weight (Mw) and polydispersity (Mw/Mn) resulted 294,500 and 1.4, respectively.

Fourier transform infrared spectroscopy (FTIR) was used to confirm the presence of the characteristic groups of the non-ionic PAM by attenuated total reflection (ATR) using an Agilent Cary 600 FTIR spectrometer. The data were collected in the range from 400 to 4000 cm⁻¹. The weight average molecular weight (M_w) of all polymers was characterized by gel permeation chromatography (GPC) (1260 Infinity Multi-Detector GPC/SEC System, Agilent Technologies, Santa Clara, CA, USA) coupled with three detectors: viscosity, refractive index, and light scattering. Two columns (PL aquagel-OH MIXED-H 8 µm, 300 × 7.5 mm) connected in series were used to obtain a better resolution and increase the instrument’s detection range. Water containing 0.15 M Na₂SO₄ and 0.05 M acetic acid was used as a mobile phase for the analysis. The characterization PVB and EPDM-g-HPMA were previously reported by our group [22 (link),23 (link)].