La spectrometer

Elemental analyses were performed on a PerkinElmer (Series II Model 2400). FTIR and NMR were recorded using a PerkinElmer 16F PC and a 500 MHz JEOL LA spectrometer, respectively. Tetramethylsilane (TMS) in CDCl₃ and residual H in D₂O at δ 4.65 ppm were used as internal standards. The ¹³C chemical shifts in D₂O were referenced against ¹³C peak of external standard dioxane at δ 67.4 ppm. Gel Permeation Chromatographic analysis was performed at 30 °C using a PL-GPC 220 manufactured by Agilent Technologies having two detectors (i.e. Refractive Index & Light Scattering), equipped with two columns (PL aquagel-OH 8 µm; 300 × 7.5 mm). Deionized water with 0.02 wt% NaN₃ was used as solvent for water soluble polymer samples. A sample solution of 5 mg/1.5 mL was prepared at ambient temperature in water having 0.02 wt% NaN₃. The resulting solution (100 µl) was injected into the GPC columns and chromatographic data was analyzed using GPC/SEC software by Agilent. In case of THF soluble polymer samples, GPC was equipped with two columns (PLgel Olexis 300 × 7.5 mm). The sample solution was prepared using tetrahydrofuran (THF) containing 0.0125 wt% antioxidant, [2,6-di-tert-butyl-4-methyl phenol (BHT)]. The equipment was calibrated using polyethylene oxide (PEO) and polystyrene (PS) standards for water-soluble and THF-soluble polymers, respectively.